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Cited by 0Sports Performance and TrainingMuscle metabolism and nutritionThermoregulation and physiological responses

Gastrointestinal Symptoms Associated With Sodium Bicarbonate Supplementation Protocols: A Systematic Review

Open access
Winter, Ian P., Sarac, Paul, Wilson, Patrick B.·2026·European Journal of Sport Science
DOI 10.1002/ejsc.70225PMC PMC13400971
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Abstract

Sodium bicarbonate positively impacts performance, but its associated gastrointestinal symptoms (GIS) may limit use. This systematic review synthesized literature that has evaluated GIS with sodium bicarbonate supplementation. Literature searches were performed from February 2024‐March 2026. Eligible studies provided ≥ 5 g of sodium bicarbonate within a 24‐h period or, if a multi‐day protocol, at least one day involving ≥ 5 g. Included studies had a placebo group/condition or a comparison group/condition that created a contrast related to delivery method, form, or dose. In total, 101 investigations were summarized in six categories: acute single dosing ( n = 35); acute spread dosing ( n = 28); chronic dosing ( n = 7); acute versus chronic dosing ( n = 5); delivery form ( n = 18); and other ( n = 8). Existing literature suggests that common acute doses (0.2–0.4 g/kg) elicit mild‐to‐severe GIS, which likely increase in a dose‐dependent manner when sodium bicarbonate is ingested in a single dose. Strategies to reduce GIS with acute dosing include spreading intake over hours, using enteric‐coated capsules/tablets, and ingesting sodium bicarbonate mini‐tablets within a carbohydrate hydrogel. Direct comparisons of these strategies to reduce GIS are absent in current literature; thus, ranking their effectiveness is not possible. Multi‐day dosing may lessen GIS, but symptom documentation throughout supplementation periods is poorly characterized. Notably, 26 of 101 studies failed to perform inferential statistical testing to examine condition/group differences in GIS. Making definitive recommendations about sodium bicarbonate supplementation to minimize GIS remains challenging. Major needs remain for direct comparisons between protocols purported to reduce GIS and improvements in GIS data collection, reporting, and analysis.

AI snapshot

Written from the paper’s full text.

TL;DR

This systematic review synthesized 101 investigations of gastrointestinal symptoms (GIS) with sodium bicarbonate supplementation and found that common acute doses (0.2–0.4 g/kg) elicit mild-to-severe GIS, likely in a dose-dependent manner. Strategies such as spreading intake over hours, enteric-coated capsules/tablets, and mini-tablets in a carbohydrate hydrogel may reduce GIS, but direct comparisons are absent and ranking their effectiveness is not possible.

Key findings

  • The review included 101 studies from 99 reports across six categories: acute single dosing (n = 35), acute spread dosing (n = 28), chronic dosing (n = 7), acute versus chronic dosing (n = 5), delivery form (n = 18), and other (n = 8).
  • In acute single dosing, 21/35 studies reported statistically greater GIS with sodium bicarbonate than comparison conditions, while 6/35 reported no apparent or significant differences; 7/35 reported GIS only descriptively without formal statistical testing.
  • Across all 101 studies, 26 failed to perform inferential statistical testing for condition/group differences in GIS.
  • Multi-day dosing may lessen GIS, but symptom documentation throughout supplementation periods is poorly characterized; direct comparisons between GIS-reduction strategies are lacking, so ranking their effectiveness is not possible.

Methods

  • Systematic review conducted with methods complying with most PRISMA aspects; searches were performed from February 2024 to March 2026 in PubMed, SPORTDiscus, and Web of Science, supplemented by screening two prior sodium bicarbonate systematic reviews.
  • Eligible studies were original human experiments providing ≥5 g sodium bicarbonate within 24 h (or, for multi-day protocols, at least one day with ≥5 g), with a placebo or comparison condition creating a contrast in delivery method, form, or dose, and reporting GIS data.
  • A narrative synthesis was used; studies were grouped into six categories, and methodological quality was assessed with the 11-item PEDro Scale. Quality ratings were excellent (24/101; 23.8%), good (61/101; 60.4%), fair (12/101; 11.9%), and poor (4/101; 4.0%).

Limitations

  • The paper states that lack of prospective protocol registration is a limitation, though the protocol was retrospectively registered on OSF; exclusion of gray literature and non-English articles could have excluded eligible articles.
  • The paper states that included studies had inconsistent timing and methods of GIS assessment, many did not focus on reducing GIS as an explicit aim, 26/101 neglected formal inferential statistical testing, and sample sizes were rarely calculated to ensure adequate power for GIS.
  • Evident from the text: high variability in GIS measurement, reporting, and analysis prevented meta-analysis and direct ranking of mitigation strategies; the authors note that definitive recommendations remain challenging.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1002/ejsc.70225

Cites

111 of 111 references verified0 citation errors · 0 not checkable

Statistics

27 tests recomputed · 1 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

51 of 148 cited sources checked · 40 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Gastrointestinal symptoms likely arise from shifts in extracellular fluid into the intestines due to an increased osmotic sodium load.

    “These GIS likely arise due to production of carbon dioxide (CO2) when bicarbonate and stomach acid react, causing bloating and belching, and from shifts in extracellular fluid into the intestines due to an increased osmotic sodium load (de Oliveira et al. 2018; Kahle et al. 2013).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites de Oliveira et al. 2018 source
    • cites Kahle et al. 2013 source
  • Premisecitation

    Sodium bicarbonate enhances performance, particularly in high-intensity activities lasting 30 seconds to 10 minutes.

    “Sodium bicarbonate enhances performance, particularly in high‐intensity activities lasting 30 seconds to 10 minutes, by acting as an extracellular buffer and maintaining pH homeostasis within the blood (Heibel et al. 2018).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Heibel et al. 2018 source

      The Exercise task section (page unavailable) supports a performance benefit from sodium bicarbonate in some high-intensity tasks, and The role of pH in skeletal muscle fatigue explains how circulating bicarbonate helps buffer hydrogen ions. But the paper gives the 30-second-to-10-minute range as a finding for beta-alanine, from which it expects comparable results for sodium bicarbonate; it also reports that a 30-second exercise test was unaffected by sodium bicarbonate. The claim presents that range too definitively for sodium bicarbonate. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
  • Premisecitation

    Doses around and above 0.2-0.3 g/kg of sodium bicarbonate have been linked to reports of gastrointestinal symptoms.

    “Of note, doses around and above 0.2–0.3 g/kg have been linked to reports of gastrointestinal symptoms (GIS) (Grgic, Pedisic, et al. 2021), which include, but are not limited to, nausea, vomiting, bloating, abdominal cramps, flatulence, and diarrhea (Dalle et al. 2019; Driller et al. 2012; Miller et al. 2016; Saunders et al. 2014; Varovic et al. 2023).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Grgic, Pedisic, et al. 2021 source
  • Premisecitation

    Gastrointestinal symptoms associated with sodium bicarbonate include nausea, vomiting, bloating, abdominal cramps, flatulence, and diarrhea.

    “Of note, doses around and above 0.2–0.3 g/kg have been linked to reports of gastrointestinal symptoms (GIS) (Grgic, Pedisic, et al. 2021), which include, but are not limited to, nausea, vomiting, bloating, abdominal cramps, flatulence, and diarrhea (Dalle et al. 2019; Driller et al. 2012; Miller et al. 2016; Saunders et al. 2014; Varovic et al. 2023).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Dalle et al. 2019 source

      The Introduction identifies stomach cramping and diarrhea as gastrointestinal problems associated with sodium bicarbonate; the Discussion also describes abdominal pain and flatulence. The paper does not identify nausea or bloating, and the vomiting reported in its Results occurred in the placebo group, not the sodium-bicarbonate group. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites Driller et al. 2012 source
    • cites Miller et al. 2016

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Premisecitation

    Gastrointestinal symptoms likely arise due to production of carbon dioxide when bicarbonate and stomach acid react, causing bloating and belching.

    “These GIS likely arise due to production of carbon dioxide (CO2) when bicarbonate and stomach acid react, causing bloating and belching, and from shifts in extracellular fluid into the intestines due to an increased osmotic sodium load (de Oliveira et al. 2018; Kahle et al. 2013).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites de Oliveira et al. 2018 source
    • cites Kahle et al. 2013 source

      The Results (section 3.d; page unavailable) report bloating after bicarbonate loading, and the Discussion (section 4; page unavailable) proposes that an osmotic load shifts fluid into the intestines and contributes to gastrointestinal distress. Our copy does not attribute symptoms to CO2 produced by a reaction with stomach acid or report belching. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
  • Classified as probably not a substantial claim. 56
  • May combine two claims. 46

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductcitation

    There was lack of clarity in Ziyaiyan et al. 2023's reporting on whether the difference in GIS was statistically significant and what conditions served as comparisons.

    “However, there was lack of clarity of reporting on whether this was statistically significant and what conditions were serving as the comparisons.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Ziyaiyan et al. 2023 source

      The Results section (‘Gastrointestinal symptoms’; page unavailable) explicitly calls the GI side effects significant and identifies the placebo group as the comparator for both the combined caffeine–sodium bicarbonate and sodium bicarbonate conditions. The Discussion repeats those comparisons, contrary to the claim that significance and comparators were unclear. (LLM, conf=0.89)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Sodium bicarbonate acts as an extracellular buffer and maintains pH homeostasis within the blood.

    “Sodium bicarbonate enhances performance, particularly in high‐intensity activities lasting 30 seconds to 10 minutes, by acting as an extracellular buffer and maintaining pH homeostasis within the blood (Heibel et al. 2018).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Heibel et al. 2018 source

  • May combine two claims.

    Premisecitation

    Sodium bicarbonate increases circulating bicarbonate and delays metabolic acidosis resulting from high-intensity exercise, thereby potentially improving performance in rowing, swimming, running, cycling, combat sports, and resistance training.

    “These effects are achieved by increasing circulating bicarbonate and delaying metabolic acidosis resulting from high‐intensity exercise, thereby potentially improving performance in rowing, swimming, running, cycling, combat sports, and resistance training (Heibel et al. 2018; Grgic, Pedisic, et al. 2021).”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites Heibel et al. 2018 source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites Grgic, Pedisic, et al. 2021 source

  • May combine two claims.

    Premisecitation

    Sodium bicarbonate's gastrointestinal side effects may negatively impact performance, limiting its use in populations that may benefit.

    “Although its ergogenic potential is well‐established, sodium bicarbonate's GIS side effects may negatively impact performance (Freis et al. 2017), limiting its use in populations that may benefit (Grgic, Pedisic, et al. 2021; Hilton et al. 2019).”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites Freis et al. 2017 source
    • cites Grgic, Pedisic, et al. 2021 source
    • cites Hilton et al. 2019 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Study quality was evaluated using the 11-item PEDro Scale.

    “Study quality was evaluated using the 11‐item PEDro Scale (de Morton 2009).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites de Morton 2009 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    The methods for this review complied with most aspects of the PRISMA guidelines.

    “The methods for this review complied with most aspects of the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines (Page et al. 2021).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Page et al. 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The greater GIS with placebo may be related to the composition of the placebo, which has in other studies shown non-zero presence of GIS.

    “possibly related to the composition of the placebo, which has in other studies shown non‐zero presence of GIS”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Dalle et al. 2019 source

      The Results report greater, non-zero GI distress with placebo than with bicarbonate. But the Discussion says sodium in the placebo was very unlikely to explain the difference and instead favors exercise-induced acidosis; it does not support the proposed link to placebo composition. No page numbers are available in our copy. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites Katagiri et al. 2023 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Time allowed to consume doses ranged from as little as 15 minutes to up to 19.5 hours.

    “Time allowed to consume doses ranged from as little as 15 minutes (Urwin et al. 2022) up to 19.5 hours (Marcus et al. 2019)”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites Urwin et al. 2022 source
    • cites Marcus et al. 2019 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Studies that did not use 0.3 g/kg provided 0.2 g/kg or 0.4 g/kg doses.

    “Those that did not provided 0.2 g/kg (Gough et al. 2022; D. G. McCarthy et al. 2023) or 0.4 g/kg (Durkalec‐Michalski et al. 2023) doses.”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Gough et al. 2022

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites D. G. McCarthy et al. 2023 source
    • cites Durkalec‐Michalski et al. 2023 source

  • May combine two claims.

    Findingcitation

    Rezaei et al. 2019 and Ziyaiyan et al. 2023 provided 0.3 g/kg/day sodium bicarbonate over a three-day span, both alone and alongside caffeine.

    “(Rezaei et al. 2019) and (Ziyaiyan et al. 2023) provided 0.3 g/kg/day over a three‐day span, both alone and alongside caffeine.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites Rezaei et al. 2019 source
    • cites Ziyaiyan et al. 2023 source

  • May combine two claims.

    Findingcitation

    Sarshin et al. 2021 supplemented with 0.5 g/kg/day sodium bicarbonate over five consecutive days, both alone and alongside creatine.

    “while (Sarshin et al. 2021) also supplemented with 0.5 g/kg/day, though this dose occurred over five consecutive days both alone and alongside creatine.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Sarshin et al. 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingnone given

    Rezaei et al. 2019, Sarshin et al. 2021, and Ziyaiyan et al. 2023 provided meals containing 1.5 g/kg carbohydrate alongside sodium bicarbonate at the time of the final dose before exercise.

    “Worth noting, (Rezaei et al. 2019), (Sarshin et al. 2021), and (Ziyaiyan et al. 2023) provided meals containing 1.5 g/kg carbohydrate alongside sodium bicarbonate at the time of the final dose before exercise.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites Rezaei et al. 2019 source

      Methods > Dietary control states that participants consumed a snack containing 1.5 g/kg body weight of carbohydrate 150 minutes before the exercise test. Methods > Supplementation protocol states that the final sodium bicarbonate dose was taken 60 minutes before the test, not at the time of the snack. This verdict concerns Rezaei et al. only. (LLM, conf=0.90)

      Experimental — accuracy not yet measured
    • cites Sarshin et al. 2021 source

      The Methods (Supplementation protocol; page unavailable) report a standardized snack containing 1.5 g/kg carbohydrate 150 minutes before each test and sodium bicarbonate supplementation in relevant groups. They describe bicarbonate as four daily doses but do not say the snack was provided alongside the final dose before exercise. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites Ziyaiyan et al. 2023 source

      Methods > Dietary control reports a standardized snack containing 1.5 g/kg body weight of carbohydrate 150 minutes before the protocol. Methods > Supplementation protocol says the final sodium bicarbonate capsule was administered 60 minutes before the protocol, so the snack was not provided alongside the final dose. (LLM, conf=0.90)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One chronic dosing study used sachets.

    “and one using sachets (Sarshin et al. 2021).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Sarshin et al. 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One of these eight investigations recorded no presence of GIS in either condition.

    “one of these recorded no presence of GIS in either condition (Macutkiewicz and Sunderland 2018).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Macutkiewicz and Sunderland 2018 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Two of the chronic dosing studies were parallel group trials.

    “Two were parallel group trials (Durkalec‐Michalski, Zawieja, Podgórski, Zawieja, et al. 2018; Sarshin et al. 2021)”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Durkalec‐Michalski, Zawieja, Podgórski, Zawieja, et al. 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Sarshin et al. 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Three chronic dosing studies provided sodium bicarbonate in gelatin capsules.

    “Three studies provided sodium bicarbonate in gelatin capsules (Delextrat et al. 2018; Rezaei et al. 2019; Ziyaiyan et al. 2023)”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Delextrat et al. 2018 source
    • cites Rezaei et al. 2019 source
    • cites Ziyaiyan et al. 2023 source

  • May combine two claims.

    Findingcitation

    Significant or apparent differences in gastrointestinal symptoms between conditions were found in only one chronic-dosing investigation (Ziyaiyan et al. 2023), which reported higher GIS ratings with two sodium bicarbonate conditions.

    “Significant or apparent differences in GIS between conditions were found in only one investigation (Ziyaiyan et al. 2023), which reported higher GIS ratings with two sodium bicarbonate conditions.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Ziyaiyan et al. 2023 source
    • Rests on an assumption: Gastrointestinal symptom outcomes assessed with different scales (10-point, 11-point, five-point) across included studies are comparable enough to be synthesized together.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Three out of five acute-versus-chronic studies used a 10-point scale to determine severity of GIS (Driller et al. 2012; Carr et al. 2012; Zhou, Fan, Kong, et al. 2022), while one used an 11-point scale (Aktitiz et al. 2024) and another a five-point scale (Joyce et al. 2012).

    “Three out of five studies used a 10‐point scale to determine severity of GIS (Driller et al. 2012; Carr et al. 2012; Zhou, Fan, Kong, et al. 2022), while one used an 11‐point scale (Aktitiz et al. 2024) and another a five‐point scale (Joyce et al. 2012).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Driller et al. 2012 source
    • cites Carr et al. 2012 source
    • cites Zhou, Fan, Kong, et al. 2022 source

  • May combine two claims.

    Findingcitation

    Gurton et al. 2025 reported no statistically significant condition effects or condition × time interactions for GIS.

    “(W. H. Gurton, Gough, et al. 2025) reported no statistically significant condition effects or condition × time interactions for GIS.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites W. H. Gurton, Gough, et al. 2025 source

  • May combine two claims.

    Findingcitation

    Both capsule-versus-solution studies provided 0.3 g/kg sodium bicarbonate in solutions and capsules acutely, though Gurton et al. 2023 provided vegetarian capsules while Hilton et al. 2019 used delayed-release capsules.

    “Both provided 0.3 g/kg in solutions and capsules acutely, though (W. H. Gurton, Matta, et al. 2023) provided vegetarian capsules while (Hilton et al. 2019) used delayed‐release capsules.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites W. H. Gurton, Matta, et al. 2023 source
    • cites Hilton et al. 2019 source

  • May combine two claims.

    Findingcitation

    Gurton et al. 2023 found no significant between-condition differences in aggregate GIS at any timepoint (all p ≥ 0.110), though mean values were not reported.

    “(W. H. Gurton, Greally, et al. 2023) found no significant between‐condition differences in aggregate GIS at any timepoint (all p ≥ 0.110), though mean values were not reported.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites W. H. Gurton, Greally, et al. 2023 source

  • May combine two claims.

    Findingcitation

    Hilton et al. 2019 found that all participants experienced GIS following solution ingestion, with lower GIS at 40-, 60-, and 80-min post-ingestion (p = 0.004; p = 0.035; p = 0.017) and overall less severe GIS following delayed-release capsules than solution (p = 0.001).

    “(Hilton et al. 2019) found that all participants experienced GIS following solution ingestion, with lower GIS at 40‐, 60‐, and 80‐min post‐ingestion (p = 0.004; p = 0.035; p = 0.017) and overall less severe GIS following delayed‐release capsules than solution (p = 0.001).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Hilton et al. 2019 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The original two searches of databases and published systematic reviews on sodium bicarbonate resulted in inclusion of 84 original studies.

    “The original two searches of databases and published systematic reviews on sodium bicarbonate resulted in inclusion of 84 original studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Thirty-two studies were split fairly evenly between provision of solutions/beverages (n = 15) and some type of capsule (n = 17).

    “Thirty‐two studies were split fairly evenly between provision of solutions/beverages (n = 15) and some type of capsule (n = 17).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Most studies used a dose of 0.3 g/kg sodium bicarbonate.

    “Most studies used a dose of 0.3 g/kg.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Studies were classified as excellent (24/101; 23.8%), good (61/101; 60.4%), fair (12/101; 11.9%), or poor (4/101; 4.0%) quality.

    “Studies were classified as excellent (24/101; 23.8%), good (61/101; 60.4%), fair (12/101; 11.9%), or poor (4/101; 4.0%) quality.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    In total, 101 investigations were summarized in six categories: acute single dosing (n = 35); acute spread dosing (n = 28); chronic dosing (n = 7); acute versus chronic dosing (n = 5); delivery form (n = 18); and other (n = 8).

    “In total, 101 investigations were summarized in six categories: acute single dosing (n = 35); acute spread dosing (n = 28); chronic dosing (n = 7); acute versus chronic dosing (n = 5); delivery form (n = 18); and other (n = 8).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    Strategies to reduce gastrointestinal symptoms with acute dosing include spreading intake over hours, using enteric-coated capsules/tablets, and ingesting sodium bicarbonate mini-tablets within a carbohydrate hydrogel.

    “Strategies to reduce GIS with acute dosing include spreading intake over hours, using enteric‐coated capsules/tablets, and ingesting sodium bicarbonate mini‐tablets within a carbohydrate hydrogel.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Third and fourth searches yielded an additional seven studies.

    “Third and fourth searches yielded an additional seven studies, and fifth and sixth searches produced another 10 eligible studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Participants were most frequently given 5-10 minutes to consume acute single doses, though some studies provided little detail on the exact time allowed to finish acute single doses.

    “Participants were most frequently given 5–10 minutes to consume acute single doses, though some studies provided little detail on the exact time allowed to finish acute single doses.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Investigations that administered different doses provided 0.18 g/kg, 0.2 g/kg, 0.21-0.24 g/kg, 0.4 g/kg, 0.43 g/kg, or 0.6 g/kg.

    “Investigations that administered different doses provided 0.18 g/kg (Poffé, Wyns, et al. 2021), 0.2 g/kg (Masoud et al. 2025), 0.21–0.24 g/kg (Ramos‐Campo et al. 2023), 0.4 g/kg (S. F. McCarthy et al. 2024), 0.43 g/kg (Dalle et al. 2019), or 0.6 g/kg (Marcus et al. 2019).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Poffé, Wyns, et al. 2021

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Masoud et al. 2025 source
    • cites Ramos‐Campo et al. 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    Mean ± SD PEDro scores were as follows for the different categories: acute single dosing (7.6 ± 1.3), acute spread dosing (7.0 ± 2.1), chronic dosing (5.7 ± 1.7), acute versus chronic dosing (7.2 ± 2.2), delivery form (6.7 ± 2.2), and other (8.3 ± 1.4).

    “Mean ± SD PEDro scores were as follows for the different categories: acute single dosing (7.6 ± 1.3), acute spread dosing (7.0 ± 2.1), chronic dosing (5.7 ± 1.7), acute versus chronic dosing (7.2 ± 2.2), delivery form (6.7 ± 2.2), and other (8.3 ± 1.4).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    In several studies, sodium bicarbonate was provided alongside another dietary supplement, including caffeine, beta-alanine, sodium citrate, and ketones.

    “In several studies, sodium bicarbonate was provided alongside another dietary supplement, including caffeine (Christensen et al. 2014; C. Correia‐Oliveira and Lopes‐Silva 2023; Higgins et al. 2016), beta‐alanine (da Silva et al. 2019), sodium citrate (Martin et al. 2025), and ketones (D. G. McCarthy et al. 2023).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Christensen et al. 2014 source
    • cites da Silva et al. 2019

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Martin et al. 2025

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Most studies allowed 30-90 minutes to consume doses.

    “though most allowed 30–90 minutes”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Remaining delivery modes included sachets, oblates, and edible film wrap.

    “Remaining delivery modes included sachets (Guimarães et al. 2020), oblates (Katagiri et al. 2023), and edible film wrap (Katagiri et al. 2024).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Guimarães et al. 2020 source
    • cites Katagiri et al. 2023 source
    • cites Katagiri et al. 2024 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One study (Martin et al. 2025) had a mixed-dose condition of 0.15 g/kg sodium bicarbonate plus 0.15 g/kg sodium citrate in addition to a 0.3 g/kg sodium bicarbonate condition.

    “One study (Martin et al. 2025) also had a mixed‐dose condition (0.15 g/kg of sodium bicarbonate + 0.15 g/kg of sodium citrate) in addition to a sodium bicarbonate condition dosed at 0.3 g/kg.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Martin et al. 2025

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Fifth and sixth searches produced another 10 eligible studies.

    “Third and fourth searches yielded an additional seven studies, and fifth and sixth searches produced another 10 eligible studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Delextrat et al. 2018 supplemented with 0.4 g/kg/day sodium bicarbonate over 3 days.

    “(Delextrat et al. 2018) supplemented with 0.4 g/kg/day over 3 days.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Delextrat et al. 2018 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    There were seven studies within the chronic dosing category.

    “There were seven studies within this category”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Total daily sodium bicarbonate doses in the chronic-dosing studies were divided into ingestion of smaller within-day doses, typically 3-4.

    “Total daily doses were divided into ingestion of smaller within‐day doses (typically 3–4).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    All other chronic dosing studies used crossover designs.

    “while all others used crossover designs.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Most studies provided sodium bicarbonate solely in capsule or tablet form (22/28).

    “Most studies provided sodium bicarbonate solely in capsule or tablet form (22/28).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Two chronic dosing studies provided sodium bicarbonate in unmarked disc-shaped dissolvable tablets.

    “two in unmarked disc‐shaped dissolvable tablets (Durkalec‐Michalski, Zawieja, Podgórski, Zawieja, et al. 2018; Durkalec‐Michalski, Zawieja, Podgórski, Łoniewski, et al. 2018)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Durkalec‐Michalski, Zawieja, Podgórski, Zawieja, et al. 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Durkalec‐Michalski, Zawieja, Podgórski, Łoniewski, et al. 2018

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One chronic dosing study failed to mention the delivery mechanism for sodium bicarbonate.

    “One study failed to mention the delivery mechanism for sodium bicarbonate (Barber et al. 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Barber et al. 2013

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Two studies did not specify exact intervals in which doses were spread, though time allotted for consumption was 30 minutes or greater.

    “Two studies did not specify exact intervals in which doses were spread, though time allotted for consumption was 30 minutes or greater (Kilding et al. 2012; Van Montfoort et al. 2004).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Kilding et al. 2012 source
    • cites Van Montfoort et al. 2004 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Both conditions within Ramos-Campo and colleagues provided sodium bicarbonate-alone and alongside ketones-without any sodium bicarbonate placebo.

    “both conditions within Ramos‐Campo and colleagues (Ramos‐Campo et al. 2023) provided sodium bicarbonate—alone and alongside ketones—without any sodium bicarbonate placebo.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ramos‐Campo et al. 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Barber et al. 2013 supplemented with 0.5 g/kg/day sodium bicarbonate alongside 20 g/day creatine monohydrate over 2 days.

    “Barber and colleagues (Barber et al. 2013) supplemented with 0.5 g/kg/day alongside 20 g/day of creatine monohydrate over 2 days”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Barber et al. 2013

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    Three investigations provided both capsules and solutions.

    “with another three investigations providing both capsules and solutions (Poffé, Wyns, et al. 2021; Dalle et al. 2021; Poffé, Ramaekers, et al. 2021).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Poffé, Wyns, et al. 2021

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Dalle et al. 2021

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Poffé, Ramaekers, et al. 2021

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    Marcus et al. 2019 compared GIS following consumption of a traditional single dose to that of an acute spread dose and found that two of seven participants reported severe GIS following the traditional dosing versus no participants after spread dosing.

    “Also of note, (Marcus et al. 2019) compared GIS following consumption of a traditional single dose to that of an acute spread dose and found that two of seven participants reported severe GIS following the traditional dosing versus no participants after spread dosing.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Marcus et al. 2019

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    In one chronic-dosing study (Barber et al. 2013), GIS assessment was carried out following repeated sprints, which occurred in the morning at least 8 h after a final sodium bicarbonate dose given the prior evening.

    “In one study, GIS assessment was carried out following repeated sprints, which occurred in the morning at least 8 h after a final sodium bicarbonate dose given the prior evening (Barber et al. 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Barber et al. 2013

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    Carr et al. 2012 and Driller et al. 2012 used greater daily doses in the chronic conditions compared to acute conditions: 0.5 g/kg/day vs. 0.3 g/kg and 0.4 g/kg/day vs. 0.3 g/kg, respectively.

    “(Carr et al. 2012) and (Driller et al. 2012) used greater daily doses in the chronic conditions compared to acute conditions. These were 0.5 g/kg/day (vs. 0.3 g/kg in acute) and 0.4 g/kg/day (vs. 0.3 g/kg in acute), respectively.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Carr et al. 2012 source
    • cites Driller et al. 2012 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Three of the five acute-versus-chronic investigations provided sodium bicarbonate in capsules (Driller et al. 2012; Carr et al. 2012; Joyce et al. 2012), while another described the treatments as 'enteric-coated' but did not specify if they were capsules or tablets (Zhou, Fan, Kong, et al. 2022).

    “Three of these investigations provided sodium bicarbonate in capsules (Driller et al. 2012; Carr et al. 2012; Joyce et al. 2012), while another one described the treatments as “enteric‐coated” but did not specify if they were capsules or tablets (Zhou, Fan, Kong, et al. 2022).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Driller et al. 2012 source
    • cites Carr et al. 2012 source
    • cites Joyce et al. 2012 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    In Carr et al. 2011, volume of fluid consumed varied from 7 to 14 mL/kg of body mass, and ingestion time was either 30 or 60 minutes.

    “Volume of fluid consumed varied from 7 to 14 mL/kg of body mass, and ingestion time was either 30 or 60 minutes.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Carr et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    Driller et al. 2012 quantified GIS pre-supplementation on the first day of chronic supplementation, as well as twice on the day of exercise.

    “Another investigation by Driller and colleagues (Driller et al. 2012) quantified GIS pre‐supplementation on the first day of chronic supplementation, as well as twice on the day of exercise.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Driller et al. 2012 source

  • May combine two claims.

    Findingcitation

    The remaining two acute-versus-chronic investigations assessed GIS on days of supplementation leading up to exercise testing, with Joyce et al. 2012 assessing GIS before capsule ingestion and Aktitiz et al. 2024 assessing GIS 90 minutes after the second (evening) dose.

    “The remaining two investigations did additionally assess GIS on days of supplementation leading up to exercise testing, though somewhat puzzlingly, Joyce and colleagues (Joyce et al. 2012) assessed GIS before capsule ingestion, while (Aktitiz et al. 2024) assessed GIS 90 minutes after the second (evening) dose.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Joyce et al. 2012 source
    • cites Aktitiz et al. 2024

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingcitation

    Chronic sodium bicarbonate doses in the acute-versus-chronic studies were most commonly administered over 3 days (Driller et al. 2012; Carr et al. 2012; Joyce et al. 2012), though four-day (Aktitiz et al. 2024) and five-day (Zhou, Fan, Kong, et al. 2022) protocols were present.

    “Chronic doses were most commonly administered over 3 days (Driller et al. 2012; Carr et al. 2012; Joyce et al. 2012), though four‐day (Aktitiz et al. 2024) and five‐day (Zhou, Fan, Kong, et al. 2022) protocols were present.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Driller et al. 2012 source
    • cites Carr et al. 2012 source
    • cites Joyce et al. 2012 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Of the eight protocols in Carr et al. 2011, four were provided as solutions, while four were provided in capsules.

    “Of the eight protocols, four were provided as solutions, while four were provided in capsules.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Carr et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    One acute-versus-chronic study provided sodium bicarbonate in a solution (Aktitiz et al. 2024).

    “One study provided sodium bicarbonate in a solution (Aktitiz et al. 2024).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Aktitiz et al. 2024

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Each chronic-dosing study used either a 10- or 11-point scale to quantify gastrointestinal symptoms.

    “Each study used either a 10‐ or 11‐point scale to quantify GIS.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    No published studies have directly compared enteric-coated capsules and SB-M, and only one investigation has compared GIS between traditional sodium bicarbonate dosing and SB-M.

    “To date, no published studies have directly compared enteric‐coated capsules and SB‐M, and only one investigation has compared GIS between traditional sodium bicarbonate dosing and SB‐M”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    The reviewed evidence reveals that the most common acute dose used (0.3 g/kg) increases risk of GIS, and while a smaller dose of 0.2 g/kg may reduce GIS severity, some individuals will still experience substantial side effects.

    “The reviewed evidence reveals that the most common acute dose used (0.3 g/kg) increases risk of GIS, and while a smaller dose of 0.2 g/kg may reduce GIS severity, some individuals will still experience substantial side effects.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    In Gurton et al. 2023, all participants receiving sodium bicarbonate, whether in capsule or solution form, experienced GIS, with gut fullness being the most prevalent.

    “In Gurton and colleagues (W. H. Gurton, Matta, et al. 2023), all participants receiving sodium bicarbonate, whether in capsule or solution form, experienced GIS, with gut fullness being the most prevalent.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites W. H. Gurton, Matta, et al. 2023

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingnone given

    Multi-day dosing strategies may mitigate GIS, especially before and during exercise, but GIS experienced throughout supplementation days is poorly characterized.

    “Multi‐day dosing strategies may mitigate GIS, especially before and during exercise, but GIS experienced throughout supplementation days is poorly characterized.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Within the 17 Acute Spread Dosing studies that conducted inferential statistical testing, only four found higher GIS with spread dosing, one found greater GIS following placebo, and 12 reported no significant differences between conditions.

    “Furthermore, within the 17 Acute Spread Dosing studies that conducted inferential statistical testing, only four found higher GIS with spread dosing (J. C. Siegler et al. 2022; Ferragut et al. 2024; Montalvo‐Alonso et al. 2024; W. H. Gurton et al. 2025), one actually found greater GIS following placebo (Dalle et al. 2019), and 12 studies reported no significant differences between conditions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    Although a dose of 0.2 g/kg reduces GIS relative to larger single doses, multiple studies reported increased GIS incidence or severity even with 0.2 g/kg.

    “Although a dose of 0.2 g/kg reduces GIS relative to larger single doses, multiple studies nonetheless reported increased GIS incidence or severity (from baseline or against placebo) even with 0.2 g/kg”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    For all types of protocols reviewed, direct comparisons between supplementation strategies are lacking, and collection, reporting, and analysis of GIS have often been less than ideal.

    “For all types of protocols reviewed, direct comparisons between supplementation strategies are lacking, and collection, reporting, and analysis of GIS have often been less than ideal.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    The largest single acute doses utilized were 0.4-0.5 g/kg of body mass, and evidence indicates these doses are likely to induce substantial GIS for a large proportion of athletes.

    “The largest single acute doses utilized were in the 0.4–0.5 g/kg of body mass range, with evidence indicating that these doses are likely to induce substantial GIS for a large proportion of athletes”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    Little attempt has been made to evaluate athletes' preferences/thoughts on factors such as ease of implementation, palatability, and user experience of different supplementation protocols.

    “Although not the focus of this review, it is apparent that little attempt has been made to evaluate athletes' preferences/thoughts on factors such as ease of implementation, palatability, and user experience of different supplementation protocols.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingcitation

    Although GIS were generally mild, Gurton et al. 2024 reported significantly higher aggregate GIS with sodium bicarbonate lotion versus combined placebo capsules and placebo lotion.

    “Although GIS were generally mild, (W. H. Gurton et al. 2024) reported significantly higher aggregate GIS with sodium bicarbonate lotion versus combined placebo capsules and placebo lotion.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites W. H. Gurton et al. 2024

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Certain elements, such as precision of estimates from studies and certainty of evidence, were impractical to summarize and report due to high variability in methods and presentation of results of included studies.

    “Certain elements (e.g., precision of estimates from studies, certainty of evidence) were impractical to summarize and report due to high variability in methods and presentation of results of included studies.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Original data extraction was performed by the primary author and then verified and corrected, if needed, by a second author.

    “Original data extraction was performed by the primary author (IPW) and then verified and corrected (if needed) by a second author (PBW).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    Study quality was ranked using categories based on PEDro Scale sum scores: poor (0-3), fair (4-5), good (6-8), and excellent (9-10).

    “Study quality was ranked using the following categories based on PEDro Scale sum scores—poor (0–3), fair (4–5), good (6–8), and excellent (9–10) (Cashin and McAuley 2020).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cashin and McAuley 2020 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Two authors independently conducted the quality assessment, and discrepancies in the scores were resolved through discussion.

    “Two authors (IPW and PS) independently conducted the quality assessment, and discrepancies in the scores were resolved through discussion.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Because of the multitude of methods that studies used to report gastrointestinal symptoms, the researchers used their judgment and discussion to determine the most relevant results to report.

    “Because of the multitude of methods that studies used to report GIS (means, medians, counts, percentages, etc.), the researchers used their judgment and discussion to determine the most relevant results to report.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    The protocol for this review was retrospectively registered and is available at the Open Science Framework.

    “The protocol for this review was retrospectively registered and is available at the Open Science Framework (OSF): https://osf.io/8a4gw/overview.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Initial screening was carried out independently by two authors, with discrepancies resolved through discussion.

    “Initial screening was carried out independently by two authors (IPW and PBW). Original records were first screened through reading titles and, if needed, abstracts and full texts. Discrepancies between authors were resolved through discussion.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    For trials evaluating complex interventions, such as gastrointestinal symptoms secondary to sodium bicarbonate supplementation, a total PEDro score of ≥8/10 is considered optimal.

    “For trials evaluating complex interventions, such as GIS secondary to sodium bicarbonate supplementation, a total PEDro score of ≥ 8/10 is considered optimal (Cashin and McAuley 2020).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Cashin and McAuley 2020 source

  • May combine two claims.

    Study design and conductcitation

    Only Joyce et al. 2012 included any statistical analysis on GIS between conditions among the acute-versus-chronic studies and found no differences in severity scores between the three conditions on any day (p > 0.05).

    “Only (Joyce et al. 2012) included any statistical analysis on GIS between conditions and found no differences in severity scores between the three conditions on any day (p > 0.05).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Joyce et al. 2012 source

  • May combine two claims.

    Premisecitation

    GIS scores from Likert scales are often right-skewed, yet most studies used parametric analytical approaches that may be inappropriate for non-normally distributed data from small sample sizes.

    “For example, GIS scores from Likert scales are often right‐skewed (Wilson 2017), yet most studies used parametric analytical approaches that may be inappropriate for non‐normally distributed data from small sample sizes.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wilson 2017 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductnone given

    Lack of prospective protocol registration is a limitation, though the protocol was retrospectively registered on OSF.

    “Lack of prospective protocol registration is a limitation, though the protocol was retrospectively registered on OSF.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Presence of less or no meaningful GIS in chronic supplementation studies may result from reduced interaction of bicarbonate and hydrochloric acid at each dose.

    “Presence of less or no meaningful GIS in these studies may result from reduced interaction of bicarbonate and hydrochloric acid at each dose.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The unclear reporting in Carr et al. 2011 is likely because a non-traditional, magnitude-based inferential analysis was used.

    “In part, this is likely because a non‐traditional, magnitude‐based inferential analysis was used.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Carr et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Reporting of significance of differences between all conditions at individual timepoints in Carr et al. 2011 was unclear.

    “However, reporting of significance of differences between all conditions at individual timepoints was unclear.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Carr et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationcitation

    Enteric-coated capsules and sodium-bicarbonate mini-tablets within a carbohydrate-hydrogel probably minimize GIS through reduced interaction of bicarbonate and hydrochloric acid, thereby reducing CO2 production in the stomach.

    “Enteric‐coated capsules and sodium‐bicarbonate mini‐tablets within a carbohydrate‐hydrogel probably minimize GIS through reduced interaction of bicarbonate and hydrochloric acid (de Oliveira et al. 2018), thereby reducing CO2 production in the stomach.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites de Oliveira et al. 2018 source

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductreasoning

    Identification of existing research occurred over several searches and was carried out by two investigators, minimizing the chance that a meaningful number of reports was missed.

    “Identification of existing research occurred over several searches and was carried out by two investigators, minimizing the chance that a meaningful number of reports was missed.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Exclusion of gray literature and non-English articles could have led to exclusion of articles that may otherwise meet the inclusion criteria.

    “Exclusion of gray literature and non‐English articles could have led to exclusion of articles that may otherwise meet the inclusion criteria.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Spreading acute doses over several hours may offer a practical, cost-effective method to elicit the ergogenic effects of sodium bicarbonate while reducing GIS, though higher total doses (0.4-0.6 g/kg) may be needed to maintain performance benefits with this strategy.

    “Spreading acute doses over several hours may offer a practical, cost‐effective method to elicit the ergogenic effects of sodium bicarbonate while reducing GIS, though higher total doses (0.4–0.6 g/kg) may be needed to maintain performance benefits with this strategy.”
    Quote in the paperSubstantial claim
87 of 87

  • The paper relies on this without support.

    Gastrointestinal symptom outcomes assessed with different scales (10-point, 11-point, five-point) across included studies are comparable enough to be synthesized together.

    “Each study used either a 10‐ or 11‐point scale to quantify GIS.”
    “Three out of five studies used a 10‐point scale to determine severity of GIS (Driller et al. 2012; Carr et al. 2012; Zhou, Fan, Kong, et al. 2022), while one used an 11‐point scale (Aktitiz et al. 2024) and another a five‐point scale (Joyce et al. 2012).”
1 of 1

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value across alpha = .05: (Z = 1.100, p = .042

    Major

    The paper reports p = .042 here; recomputing from the test statistic and its degrees of freedom gives p = .271 (two-tailed). The two fall on opposite sides of alpha = .05. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .042 · recomputed p = .271

  • Inconsistent p-value: (z = 0.02, p = .92

    Minor

    The paper reports p = .92 here; recomputing from the test statistic and its degrees of freedom gives p = .984 (two-tailed). The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .92 · recomputed p = .984

  • Inconsistent p-value: χ2(3) = 3.051, p = .351

    Minor

    The paper reports p = .351 here; recomputing from the test statistic and its degrees of freedom gives p = .384. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .351 · recomputed p = .384

  • Inconsistent p-value: Z = 1.76, p = .07

    Minor

    The paper reports p = .07 here; recomputing from the test statistic and its degrees of freedom gives p = .078 (two-tailed). The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .07 · recomputed p = .078

  • Inconsistent p-value: χ2(3) = 9.314, p = .026

    Minor

    The paper reports p = .026 here; recomputing from the test statistic and its degrees of freedom gives p = .025. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .026 · recomputed p = .025

5 of 5

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upz = 1.1reported p = .042 · recomputed p = .271The two fall on opposite sides of .05

    “(Z = 1.100, p = .042”

  • Doesn’t add upz = 1.76reported p = .07 · recomputed p = .078

    “Z = 1.76, p = .07”

  • Doesn’t add upχ²(3) = 9.314reported p = .026 · recomputed p = .025

    “χ2(3) = 9.314, p = .026”

  • Doesn’t add upχ²(3) = 3.051reported p = .351 · recomputed p = .384

    “χ2(3) = 3.051, p = .351”

  • Doesn’t add upz = 0.02reported p = .92 · recomputed p = .984

    “(z = 0.02, p = .92”

  • Not confirmedz = 1.5reported p = .018 · recomputed p = .134

    “(Z = 1.500, p = .018”

  • Not confirmedz = 1.385reported p = .037 · recomputed p = .166

    “(Z = 1.385, p = .037”

  • Not confirmedz = 1.04reported p = .31 · recomputed p = .298

    “(z = 1.04, p = .31”

  • Consistentz = 2.032reported p = .042 · recomputed p = .042

    “(z = 2.032, p = .042”

  • Consistentz = 2.232reported p = .026 · recomputed p = .026

    “(z = 2.232, p = .026”

  • Consistentz = -1.89reported p = .06 · recomputed p = .059

    “Z = −1.89, p = .06”

  • Consistentχ²(3) = 11.319reported p = .01 · recomputed p = .010

    “χ2(3) = 11.319, p = .010”

  • Consistentz = -2.903reported p = .004 · recomputed p = .004

    “(z = −2.903, p = .004”

  • Consistentχ²(3) = 5.25reported p = .154 · recomputed p = .154

    “χ2(3) = 5.250, p = .154”

  • Consistentχ²(3) = 5.797reported p = .122 · recomputed p = .122

    “χ2(3) = 5.797, p = .122”

  • Consistentχ²(3) = 2.971reported p = .396 · recomputed p = .396

    “χ2(3) = 2.971, p = .396”

  • Consistentχ²(2) = 0.095reported p = .953 · recomputed p = .954

    “χ2(2) = 0.095, p = .953”

  • Consistentχ²(2) = 4.414reported p = .11 · recomputed p = .110

    “χ2(2) = 4.414, p = .110”

  • Consistentχ²(2) = 3.161reported p = .206 · recomputed p = .206

    “χ2(2) = 3.161, p = .206”

  • Consistentχ²(2) = 3.935reported p = .14 · recomputed p = .140

    “χ2(2) = 3.935, p = .140”

  • ConsistentF(6, 63) = 0.173reported p = .983 · recomputed p = .983

    “F(6, 63) = 0.173, p = .983”

  • ConsistentF(3, 63) = 1.88reported p = .142 · recomputed p = .142

    “F(3, 63) = 1.880, p = .142”

  • Consistentz = -1.71reported p = .088 · recomputed p = .087

    “z = −1.71, p = .088”

  • Consistentz = -0.51reported p = .61 · recomputed p = .610

    “z = − 0.51, p = .61”

  • Consistentz = -1.45reported p = .15 · recomputed p = .147

    “z = −1.45, p = .15”

  • Consistentz = 0.23reported p = .82 · recomputed p = .818

    “z = 0.23, p = .82”

  • Consistentz = 0.42reported p = .67 · recomputed p = .674

    “z = 0.42, p = .67”

27 of 27

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Reported 95% confidence interval conflicts with nonsignificant p-value

    Minor

    For the same enteric-coated versus gelatin-capsule GIS difference, the reported 95% confidence interval is entirely above zero, while the reported p-value is 0.211. Those give conflicting indications of whether the difference is statistically significant.

  • Sarshin results name a caffeine condition absent from its listed treatments

    Minor

    Table 4 attributes a significant GIS result for a CAF + SB combination to Sarshin et al. 2021, but the conditions and dosing listed for that study include creatine, not caffeine.

  • A study said to lack numerical GIS values has a reported mean and range

    Minor

    The acute spread-dosing narrative names Poffé, Ramaekers, et al. 2021 as lacking numerical GIS values. Table 3 gives a mean GIS score and range for that study.

3 of 3

Cites

Flagged first, then by citations

Authors
Winter, I. P., Sarac, P., & Wilson, P. B.
Affiliations
Old Dominion University (US)
ORCID
Wilson, Patrick B.
Venue
European Journal of Sport Science
Publisher
Wiley
Published
2026-07-24
Volume
26
Issue
8
Pages
e70225-e70225
ISSN
  • 1536-7290 (ISSN-L)
  • 1746-1391
DOI
10.1002/ejsc.70225
PMC
PMC13400971
OpenAlex
W7171172087
Semantic Scholar
174a7aed84191e9c213ed03d041f452f35af6826
Cited by
0
References
62
FWCI
0.00
Type
journal article
Language
en
Open access
Licence
Locations
  • European Journal of Sport Science (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
  • ODU Digital Commons (Old Dominion University) (submittedVersion, cc-by-nc)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • PubMed Central (submittedVersion, cc-by-nc)
Topics
  • Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Health Sciences › Medicine › Physiology › Thermoregulation and physiological responses
Keywords
sodium bicarbonate, gastrointestinal symptoms, sports supplementation, chronic dosing, enteric-coated tablets, dose dependence
MeSH terms
Gastrointestinal Diseases, Humans, Sodium Bicarbonate, Dietary Supplements

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-18.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-18.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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