The DOI matches its Crossref record; 29 of the 30 references it cites were found in a registry or an index.
Timing of Levothyroxine Administration Affects Serum Thyrotropin Concentration
Open accessAbstract
CONTEXT: Patients treated with levothyroxine typically ingest it in a fasting state to prevent food impairing its absorption. The serum thyrotropin concentration is the therapeutic index of levothyroxine action. OBJECTIVE: The study objective was to determine the effect of the timing of levothyroxine administration in relationship to food on serum thyrotropin levels. DESIGN: Participants were randomized to one of six sequences, each consisting of three 8-wk regimens in a three-period crossover design. These regimens were in a fasting state, at bedtime, and with breakfast. The concentrations of TSH, free T(4), and total T(3) during each of the three timing regimens were documented. The primary outcome was the difference between serum TSH concentrations under fasting conditions compared with concentrations during the other 8-wk regimens. SETTING: The study was conducted in an academic medical center. PARTICIPANTS: Study participants were receiving levothyroxine for treatment of hypothyroidism or thyroid cancer. RESULTS: Sixty-five patients completed the study. The mean thyrotropin concentration was 1.06 +/- 1.23 mIU/liter when levothyroxine was administered in the fasting state. When levothyroxine was taken with breakfast, the serum thyrotropin concentration was significantly higher (2.93 +/- 3.29 mIU/liter). When levothyroxine was taken at bedtime, the serum TSH concentration was also significantly higher (2.19 +/- 2.66 mIU/liter). CONCLUSION: Nonfasting regimens of levothyroxine administration are associated with higher and more variable serum TSH concentrations. If a specific serum TSH goal is desired, thereby avoiding iatrogenic subclinical thyroid disease, then fasting ingestion of levothyroxine ensures that TSH concentrations remain within the narrowest target range.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“In a study which compared three timing regimens in 65 patients with primary hypothyroidism, a with-breakfast dosing resulted in the highest and most variable TSH levels, while a regimen of LT4 being administered an hour before breakfast was associated with the lowest and least variable TSH; the bedtime LT4 regimen produced values and variability that was in-between the other two dosing regimens (4”
From ETA guidelines for the use of levothyroxine sodium preparations in monotherapy to optimize the treatment of hypothyroidism (2025) · cites this paper as [41]
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“Two recent cross-over studies had different findings with the lowest serum TSH values being seen either 1 hour before breakfast or at bedtime (128,129).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [128]
The cited source says what the claim attributes to it.
In the citing paper
“The mean TSH values seen with these different conditions were 1.06, 2.93, and 2.19 mIU/L respectively (128).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [128]
The cited source says what the claim attributes to it.
In the citing paper
“Four studies (121,126,128,129), out of the six studies examining this issue (121,128-131), have shown that the timing of LT4 administration influences the serum TSH values of hypothyroid patients receiving treatment.”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [128]
In the citing paper
“Coingestion with breakfast or coffee can reduce and delay absorption (21, 22).”
From Levothyroxine: conventional and novel drug delivery formulations. (2023) · cites this paper as [21]
In the citing paper
“Bach-Huynh et al. three-period crossover study of 65 LT4-treated stable hypothyroid patients found that non-fasting LT4 administration was associated with higher and more variable serum TSH concentrations [ 33 ].”
From Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults (2022) · cites this paper as [33]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
The Clinical Significance of Subclinical Thyroid Dysfunction
Biondi, B., & Cooper, D. S. (2008) · Endocrine Reviews · doi:10.1210/er.2006-0043 · Cited by 1,418
Outcomes of Patients with Differentiated Thyroid Carcinoma Following Initial Therapy
Jonklaas, J., Sarlis, N. J., Litofsky, D. R., Ain, K. B., Bigos, S. T., Brierley, J. D., Cooper, D. S., Haugen, B. R., Ladenson, P. W., Magner, J. A., et al. (2006) · Thyroid · doi:10.1089/thy.2006.16.1229 · Cited by 693
Andersen, S., Pedersen, K. M., Bruun, N. H., & Laurberg, P. (2002) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem.87.3.8165 · Cited by 686
Fish, L. H., Schwartz, H. L., Cavanaugh, J., Steffes, M. W., Bantle, J. P., & Oppenheimer, J. H. (1987) · New England Journal of Medicine · doi:10.1056/nejm198703263161302 · Cited by 353
Thyroxine in Goiter, Helicobacter pylori Infection, and Chronic Gastritis
Centanni, M., Gargano, L., Canettieri, G., Viceconti, N., Franchi, A., Fave, G. D., & Annibale, B. (2006) · New England Journal of Medicine · doi:10.1056/nejmoa043903 · Cited by 329
Ferrous sulfate reduces thyroxine efficacy in patients with hypothyroidism
Campbell, N. R. C., Hasinoff, B. B., Stalts, H., Rao, B., & Wong, N. C. W. (1992) · Annals of Internal Medicine · doi:10.7326/0003-4819-117-12-1010 · Cited by 231
Effect of calcium carbonate on the absorption of levothyroxine
Singh, N. (2000) · JAMA · doi:10.1001/jama.283.21.2822 · Cited by 219
CARR, D., MCLEOD, D. T., PARRY, G., & THORNES, H. M. (1988) · Clinical Endocrinology · doi:10.1111/j.1365-2265.1988.tb01219.x · Cited by 210
Altered intestinal absorption of L-thyroxine caused by coffee
Benvenga, S., Bartolone, L., Pappalardo, M. A., Russo, A., Lapa, D., Giorgianni, G., Saraceno, G., & Trimarchi, F. (2008) · Thyroid · doi:10.1089/thy.2007.0222 · Cited by 191 · cited 2×
“Additional factors affecting the absorption of LT4 are food (1–4, 22, 23), including high-fiber diets (24), soy (25), and beverages (26).”
BackgroundDelayed Intestinal Absorption of Levothyroxine
BENVENGA, S., BARTOLONE, L., SQUADRITO, S., GIUDICE, F. L., & TRIMARCHI, F. (1995) · Thyroid · doi:10.1089/thy.1995.5.249 · Cited by 156
Flagged first, then by citations
1 of the 30 references couldn’t be matched to a known paper.
Research works printed but not linked: 2
- Lamson, 2004, Quantitation of a substantial reduction in levothyroxine (T4) absorption by food, Thyroid, 14, 876
- Elliott, 2001, Effect of levothyroxine administration time on serum TSH in elderly patients., Ann Pharmacother, 35, 529, 10.1345/aph.10286 · DOI · Paper page
Cited by
Sorted by citations
Items 101–198 of 198
Recent review on medical treatment of thyroid disease
Park, K. H., & Lee, E. J. (2012) · Journal of Korean Medical Association · doi:10.5124/jkma.2012.55.12.1207 · Cited by 10
“이론적으로는 식사 후 4시간이면 공복이지만, 아침식 사 전 공복에 복용하는 방법이 TSH를 좁은 범위 안에 유지 할 수 있었고[14], 자기 전 복용한 경우 아침 공복에 복용한 경우보다 fT4 수치가 더 높았으나 삶의 질 척도에서는 차이 가 없었기 때문에[15], 기상 후 식사하기 최소 30분 전에 갑 상선호르몬제를 복용하도록 권하고 있다.”
The TRHR Gene Is Associated with Hypothalamo-Pituitary Sensitivity to Levothyroxine
Brigante, G., Spaggiari, G., Santi, D., Cioni, K., Gnarini, V. L., Diazzi, C., Pignatti, E., Casarini, L., Marino, M., Tüttelmann, F., et al. (2014) · European Thyroid Journal · doi:10.1159/000358590 · Cited by 11
Drug administration adjustments for elderly patients with dysphagia: A case report
Mastroianni, P. D. C., & Forgerini, M. (2018) · Dementia & Neuropsychologia · doi:10.1590/1980-57642018dn12-010015 · Cited by 10
Morning vs. bedtime levothyroxine administration: what is the ideal choice for children?
Akın, O. (2018) · Journal of Pediatric Endocrinology and Metabolism · doi:10.1515/jpem-2018-0168 · Cited by 10
Definition, Causes, Pathophysiology, and Management of Hypothyroidism
Bereda, G. (2023) · Mathews Journal of Pharmaceutical Science · doi:10.30654/mjps.10014 · Cited by 10
“Extra exogenous thyroid hormone raises the risk of fracture and lowers bone density [17-21].”
BackgroundMalabsorption of L-T4 due to drip coffee: a case report using predictors of causation
Wegrzyn, N. M. (2016) · Journal of the Academy of Nutrition and Dietetics · doi:10.1016/j.jand.2016.02.016 · Cited by 9
de Mello, R. B., Giassi, K., Stahl, G., Machado Assis, M. L., Flores, M. S., de Lima, B. C., Piccoli, V., & da Costa Rodrigues, T. (2022) · Frontiers in Medicine · doi:10.3389/fmed.2022.828762 · Cited by 9
“(29) and Bach-Huynhm (30) did not exclude participants using known LT4 interfering medications from their trials.”
BackgroundInfluentialOteri, V., Volpe, S., Lopes, M., Sceusa, G., Tumminia, A., Belfiore, A., Frasca, F., & Gullo, D. (2024) · Endocrine · doi:10.1007/s12020-024-04016-7 · Cited by 9
“To avoid alterations in intestinal absorption, L-T4 tablets must be taken on an empty stomach, preferably 60 min before breakfast [26].”
Ala, S., Akha, O., Kashi, Z., Bahar, A., Rad, H. A., Sasanpour, N., & Shiva, A. (2015) · International Journal of Endocrinology · doi:10.1155/2015/156375 · Cited by 9
“[16] reported increased serum TSH levels and reduction in serum T4 levels in response to changing the levothyroxine administration time frommorning to evening.”
BackgroundKumarathunga, P. A. D. M., Kalupahana, N. S., & Antonypillai, C. N. (2021) · Endocrinology, Diabetes & Metabolism Case Reports · doi:10.1530/edm-21-0070 · Cited by 9
Long-Term Adherence to Levothyroxine Replacement Therapy in Thyroidectomized Patients
Bocale, R., Desideri, G., Barini, A., D’Amore, A., Boscherini, M., Necozione, S., & Lombardi, C. P. (2022) · Journal of Clinical Medicine · doi:10.3390/jcm11154296 · Cited by 9
“The lowest absorption occurs when the drug is taken together with breakfast [9,10].”
BackgroundElmor, R., Sandulli, W., & Carter, C. A. (2017) · Pharmacoeconomics open access · doi:10.4172/2472-1042.1000113 · Cited by 10
CACA guidelines for holistic integrative management of thyroid cancer
Ge, M., Gao, M., Cheng, R., Chen, X., Guan, H., Lin, Y., Liu, S., Wang, Y., Zheng, C., & Zheng, X. (2022) · Holistic Integrative Oncology · doi:10.1007/s44178-022-00015-8 · Cited by 7
Alternative schedules of levothyroxine administration
Geer, M., Potter, D. M., & Ulrich, H. (2015) · American Journal of Health-System Pharmacy · doi:10.2146/ajhp140250 · Cited by 7
Effect of Ramadan Fasting on Thyroid Hormone Levels in Patients on Levothyroxine Treatment
Dellal, F. D., Ogmen, B. E., Özdemir, D., Alkan, A., Neslihan, F., Polat, Ş. B., Ersoy, R., & Çakır, B. (2020) · Journal of College of Physicians And Surgeons Pakistan · doi:10.29271/jcpsp.2020.10.1009 · Cited by 7
Elsherbiny, T. M. (2021) · Dubai Diabetes and Endocrinology Journal · doi:10.1159/000513927 · Cited by 6
Лікування гіпотиреозу згідно із сучасними клінічними настановами
Pashkovska, N. V. (2016) · INTERNATIONAL JOURNAL OF ENDOCRINOLOGY (Ukraine) · doi:10.22141/2224-0721.6.78.2016.81860 · Cited by 7
Management of common endocrine conditions other than diabetes mellitus during ramadan fasting
Beshyah, S., Fiad, T. M., & Saadi, H. (2012) · Ibnosina Journal of Medicine and Biomedical Sciences · doi:10.4103/1947-489x.210770 · Cited by 6
Hypothyroidism—should levothyroxine be taken at bedtime?
Vanderpump, M. P. J. (2011) · Nature Reviews Endocrinology · doi:10.1038/nrendo.2011.29 · Cited by 6
“66 mIU/l if taken before breakfast, with breakfast or at bedtime, respectively)”
Jonklaas, J. (2019) · Springer eBooks · doi:10.1007/978-3-319-72102-6_19 · Cited by 6
Bianchini, B. V., de Jesus, P. R., de Mello, R. G. B., Ziegelmann, P. K., Filion, K. B., & Pizzol, T. D. S. D. (2024) · Expert Review of Clinical Pharmacology · doi:10.1080/17512433.2024.2313616 · Cited by 6
Mazeto, G. M. F. D. S., Sgarbi, J. A., Ramos, H. E., Villagelin, D., Nogueira, C. R., Vaisman, M., Graf, H., & de Carvalho, G. A. (2022) · Archives of Endocrinology and Metabolism · doi:10.20945/2359-3997000000545 · Cited by 7
“Levels of TSH have been shown to be higher when LT4 is taken with breakfast versus during fasting, although the levels remained within the normal range in both conditions (79,80).”
BackgroundRamadan and Hypothyroidism: Impact of Ramadan Fasting on Thyroid Status
Drissi Oudghiri, M., Motaib, I., Elamari, S., Laidi, S., & Chadli, A. (2022) · Medical and Clinical Research Open Access · doi:10.52106/2766-3213.1039 · Cited by 6
2023 Korean Thyroid Association Management Guidelines for Patients with Subclinical Hypothyroidism
Chung, H. K., Ku, E. J., Yoo, W. S., Kang, Y. E., Kim, K. J., Kim, B. H., Kim, T. Y., Park, Y. J., Ahn, C. H., Yoon, J. H., et al. (2023) · International Journal of Thyroidology · doi:10.11106/ijt.2023.16.1.32 · Cited by 6
Clinically Relevant Complications of Drug-Food Interactions in Psychopharmacology
Carlo, A. D., & Alpert, J. E. (2016) · Psychiatric Annals · doi:10.3928/00485713-20160613-01 · Cited by 5
Cappelli, C., Pirola, I., & Castellano, M. (2020) · Case Reports in Endocrinology · doi:10.1155/2020/8858887 · Cited by 5
P-glycoprotein polymorphism and levothyroxine bioavailability in hypothyroid patients
Öztaş, E., Garcia-Saavedra, A. P., Yanar, F., Özçınar, B., Aksakal, N., Purısa, S., & Özhan, G. (2017) · Saudi Pharmaceutical Journal · doi:10.1016/j.jsps.2017.11.012 · Cited by 5
“The success of the treatment depends on L-T4 bioavailability, which is affected by several factors such as timing of administration (Bach-Huynh et al., 2009), body mass (Santini et al.”
BackgroundWillems, J. I. A., van Twist, D. J. L., Helmich, F., Sluiter, T., Medici, M., Peeters, R. P., & van Wijngaarden, R. F. A. T.-D. L. (2025) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/clinem/dgaf686 · Cited by 4
Investigation of Alginate-Chitosan nanoparticles As a Drug Carrier for Levothyroxine
Rostami, E. (2024) · Jundishapur Journal of Natural Pharmaceutical Products · doi:10.5812/jjnpp-150307 · Cited by 4
“Therefore, to minimize interactions, levothyroxine should be taken 30 minutes to one hour before eating or drinking anything (12, 13).”
Evaluation of the common mistakes made by patients in the use of Levothyroxine
Küçükler, F. K., Akbaba, G., Arduç, A., Şimşek, Y., & Güler, S. (2014) · European Journal of Internal Medicine · doi:10.1016/j.ejim.2014.09.002 · Cited by 4
Recommended management of thyroid disorders
Weetman, A. P. (2016) · Prescriber · doi:10.1002/psb.1522 · Cited by 4
Evaluation of evening versus morning levothyroxine intake in elderly (MONIALE)
Giassi, K. D. S., Piccoli, V., Rodrigues, T. D. C., & de Mello, R. G. B. (2019) · Trials · doi:10.1186/s13063-019-3816-3 · Cited by 5
“001) than when taking it 20 min before breakfast or 2 h after supper [42].”
BackgroundFactors Associated with Medicine Timing Effects: A Meta-analysisPreprint
Ruben, M. D., Francey, L. J., Wu, G., Smith, D. F., FitzGerald, G. A., Hughey, J., & Hogenesch, J. B. (2021) · medRxiv · doi:10.1101/2021.10.24.21265348 · Cited by 4
Breakfast Habits in Patients Using Levothyroxine: Patient Experiences and Preferences
Willems, J. I. A., van Twist, D. J. L., Luu, I. H. Y., Bianchi, R., Peeters, R. P., & van Wijngaarden, R. F. A. T.-D. L. (2024) · Journal of the Endocrine Society · doi:10.1210/jendso/bvae180 · Cited by 3
Clinical Practice Recommendations for Assessment and Management of Hypothyroidism
Alsifri, S. N., Aljuhani, N. R., Al-Jedai, A. H., Nasser, T., Alsabaan, F., Almudaiheem, H., Amir, A., Baissa, E., Ghannam, N., Aldawish, M., et al. (2022) · International Journal of Clinical Medicine · doi:10.4236/ijcm.2022.1312046 · Cited by 4
Comparative Bioavailability of a Novel Solution and a Tablet Formulation of Levothyroxine
Vandse, S., Psarrakis, Y., Washington, K., & Baron, M. A. (2023) · Clinical pharmacology in drug development · doi:10.1002/cpdd.1233 · Cited by 2
Tesař, O., Měrková, V., Doseděl, M., & Malý, J. (2020) · Klinická farmakologie a farmacie · doi:10.36290/far.2020.020 · Cited by 3
Eligar, V. S., Taylor, P. N., Okosieme, O. E., & Dayan, C. M. (2016) · Elsevier eBooks · doi:10.1016/b978-0-12-803592-4.00077-8 · Cited by 3
Hypothyroidism and Subclinical Hypothyroidism in the Older Patient
Gurevitz, S. L., Snyder, J. A., Peterson, K. L., & Kelly, K. L. (2011) · The Consultant Pharmacist · doi:10.4140/tcp.n.2011.657 · Cited by 3
Early detection of biochemically occult autonomous thyroid nodules
Brusca, N., Virili, C., Cellini, M., Capriello, S., Gargano, L., Salvatori, R., Centanni, M., & Santaguida, M. G. (2016) · European Journal of Endocrinology · doi:10.1530/eje-16-0568 · Cited by 3
Sakr, M. F. (2020) · Springer eBooks · doi:10.1007/978-3-030-48775-1_10 · Cited by 3
Winter, W. E., Schatz, D., & Bertholf, R. L. (2012) · Elsevier eBooks · doi:10.1016/b978-1-4160-6164-9.00055-x · Cited by 3
Russo, M., Gullo, D., Tumino, D., Leonardi, D., Malandrino, P., & Frasca, F. (2022) · Clinical Endocrinology · doi:10.1111/cen.14738 · Cited by 2
Islamic Fasting and Thyroid Hormones
Azizi, F. (2015) · Intern J Endocrinol Metab · doi:10.5812/ijem.29248 · Cited by 3
Gatta, E., Maltese, V., Cavadini, M., Anelli, V., Bambini, F., Buoso, C., Facondo, P., Pirola, I., Delbarba, A., & Cappelli, C. (2023) · Endocrine Practice · doi:10.1016/j.eprac.2023.08.009 · Cited by 2
Wu, Y., Zhang, Z., Qin, W., Chen, W., & Xu, T. (2025) · Frontiers in Oncology · doi:10.3389/fonc.2025.1441726 · Cited by 2
“Indeed, the timing of taking the levothyroxine, the knowledge of the different forms of levothyroxine, and the risks associated with self-adjustment are important points since they can in fl uence the TSH levels (27 – 29).”
Attinger, M., von Felten, S., Rodrigues, C. L., Krützfeldt, J., Risch, L., & Bonzon, J. (2025) · Clinical and Translational Science · doi:10.1111/cts.70409 · Cited by 2
Study of Therapeutic Response on Variable Levothyroxine Supplementation in Hypothyroidism
(2018) · International Journal of Clinical Chemistry and Laboratory Medicine · doi:10.20431/2455-7153.0402005 · Cited by 1
“Approximately one in 50 women and 1 in 1000 men suffers with hypothyroidism in their life and TSH (Thyroid stimulating Hormone, secreted by Pituitary gland) level is a most sensitive index, as elevated TSH level always suggest under activity of thyroid.(22-28) Though various dose schedule been clinically evaluated but…”
BackgroundLee, K. P., Ah, Y., & Choi, H. D. (2020) · Korean Journal of Clinical Pharmacy · doi:10.24304/kjcp.2020.30.2.87 · Cited by 2
“Am J Gastroenterol 1994;89(9):1489-1495.”
The absorption of liquid levo-thyroxine is not significantly impaired by food intake.
Luca, F. D. (2016) · Acta bio-medica dell'Ateneo parmense/Acta biomedica · Cited by 2
Navid, A., Dayal, D., Kaur, H., Gupta, A., & Attri, S. V. (2021) · Pediatric Endocrinology Diabetes and Metabolism · doi:10.5114/pedm.2021.105635 · Cited by 2
“The authors suggested that fasting ingestion of levothyroxine should be advised when a specific serum TSH goal is desired [17].”
BackgroundResultEfficacy of Ujjayi Pranayama on Hypothyroidism in Adults: A Randomized Controlled Trial
Vinudha, S. (2019) · Cited by 2
One sip of water with LT-4 supplementation—a key to euthyroidism in Hashimoto’s thyroiditis
Schnedl, W. J., Michaelis, S., Mangge, H., & Enko, D. (2024) · Endocrine · doi:10.1007/s12020-024-03829-w · Cited by 1
“Patients with TSH values above the normal range should be reassessed to ensure that L-T4 is being administered correctly [21] and that all known factors interfering with L-T4 absorption have been addressed [22, 23].”
BackgroundAlabedi, R. F., Abdullah, W. H., & Alsaffar, H. (2025) · Medical Journal of Babylon · doi:10.4103/mjbl.mjbl_1222_23 · Cited by 1
Al-Mutawa, N., Mussa, B. M., Akhlaq, S., AbdulWahid, Z., & Qawas, A. (2025) · Frontiers in Endocrinology · doi:10.3389/fendo.2025.1513904 · Cited by 1
da Rocha, B. S., Silveira, V. B., Rados, D. R. V., Zanella, A. B., Scheffel, R. S., Maia, A. L., & Dora, J. M. (2025) · Endocrine · doi:10.1007/s12020-025-04229-4 · Cited by 2
“Among these studies, six were crossover trials [18, 20 – 24].”
InfluentialBaratta, F., Moscucci, F., Bocale, R., Savoia, C., Cocomello, N., Lospinuso, I., Ettorre, E., Desideri, G., & Pontecorvi, A. (2025) · Metabolites · doi:10.3390/metabo15080547 · Cited by 1
Management of thyroid diseases and steroid replacement in Ramadan: A review study
Hameed, M., & Raza, S. (2016) · DOAJ (DOAJ: Directory of Open Access Journals) · doi:10.22038/jfh.2016.7332 · Cited by 1
“While consumption of thyroxine with food is not advised (12), it could be taken at bedtime since it exerts the same effects as when it is taken on an empty stomach (13, 14).”
BackgroundApproach to Subclinical Hypothyroidism in Adults
Coloma, J. N. L., & Noboa, N. L. (2022) · International Journal of Medical and Surgical Sciences · doi:10.32457/ijmss.v9i2.1883 · Cited by 1
Beshyah, S., Khalil, A., Beshyah, A. S., Benbarka, M., & Sherif, I. (2023) · Journal of Diabetes and Endocrine Practice · doi:10.1055/s-0043-176327 · Cited by 1
Simultaneous Intake of Liquid L-T4 Formulation and Iron Salt: Fact or Fiction?
Maltese, V. (2023) · Acta Endocrinologica (Bucharest) · doi:10.4183/aeb.2023.54 · Cited by 2
Thyroxine Replacement Therapy during Ramadan Fasting: A Narrative Review
Aljaberi, A. K., Alamoudi, R. M., Elsherbiny, T. M., Hafidh, K., Raza, S. A., & Beshyah, S. (2024) · Journal of Diabetes and Endocrine Practice · doi:10.1055/s-0044-1791485 · Cited by 1
Thyroid hormones, iodine, and antithyroid drugs
Boelaert, K. (2012) · Side effects of drugs annual · doi:10.1016/b978-0-444-59499-0.00041-6 · Cited by 1
Importance of Thyroid Hormone Replacement Therapy in Patients with Medullary Thyroid Cancer
Jonklaas, J. (2016) · Springer eBooks · doi:10.1007/978-3-319-39412-1_13 · Cited by 1
Emerson, C. H. (2018) · Clinical Thyroidology · doi:10.1089/ct.2018;30.456-459 · Cited by 1
“Although it is generally agreed that thyroid hormone tablets are best not taken with meals, there are only a few studies and brief reports supporting this idea , some of which are cited here (2-6).”
Alendronato de sódio, levotiroxina e inibidores da bomba de prótons
Sousa, C. T., Gomes, G. K. A., Pichitelli, J. D. S. D., Tinoco, M. S., Pereira, L. R. L., Pereira, M. L., & Baldoni, A. O. (2021) · Revista Brasileira de Medicina de Família e Comunidade · doi:10.5712/rbmfc16(43)2486 · Cited by 1
Campanini, M., & Grandi, M. (2017) · Italian Journal of Medicine · doi:10.4081/itjm.q.2017.3 · Cited by 1
Thyroid hormones, iodine, and antithyroid drugs
Boelaert, K. (2011) · Side effects of drugs annual · doi:10.1016/b978-0-444-53741-6.00041-6
Miyoshi, Y. (2013) · Journal of Endocrinology and Metabolism · doi:10.4021/jem.v2i6.129
“showed that TSH levels were higher when LT4 was taken at bedtime instead of before breakfast [4].”
BackgroundThyroid Replacement Therapy: The Hidden Challenges
Rahim, A., & Goundrey-Smith, S. (2014) · Journal of Endocrinology and Metabolism · doi:10.4021/jem.v3i6.200
“This is normally taken in the morning 30 min before breakfast to prevent malabsorption that may occur if taken with food [14].”
BackgroundRuchała, M., Szczepanek‐Parulska, E., & Zybek, A. (2012) · PubMed · Cited by 37
Does Timing of Thyroxine Dosing Matter
Brett, A. S. (2009) · Journal watch · doi:10.1056/jw200910270000007
Alorda, M., Squillace, C., Álvarez, P., Kassis, S., Mazzeo, M., Salas, G., & Torresani, M. (2015)
Kaynar, A. M., & Bhatnagar, N. (2015) · Springer eBooks · doi:10.1007/978-1-4614-7495-1_199
Levothyroxine Therapy: When Outcomes Are Less Than Optimal-Optimizing Patient Care
Hennessey, J. V. (2016) · The Endocrine Society eBooks · doi:10.1210/mtp5.9781943550043.ch68
Guías de práctica clínica para el tratamiento del hipotiroidismo
Brenta, G., Vaisman, M., Sgarbi, J. A., de Andrada, N. C., Bravo, P. P., Orlandi, A. M., & Graf, H. (2013)
Patient Compliance and Awareness with Thyroid Replacement Therapy
Medicine, A. P. O. I., & Balla, D. A. A. (2016) · Journal of Medical Science And clinical Research · doi:10.18535/jmscr/v4i12.126
Ha, J., & Lim, D. J. (2017) · Korean Journal of Medicine · doi:10.3904/kjm.2017.92.3.245
“환자에서는 반드시 아침 식사 한 시간 전 공복에 복용 을 하도록 교육하여야 하나[13], 단순 갑상선기능저하”
Letter to Editor about "Hypothyroidism and Ramadan Fasting"
Azizi, F. (2015) · DOAJ (DOAJ: Directory of Open Access Journals) · doi:10.22038/jfh.2015.4171
Yazıcı, D. (2018) · Springer eBooks · doi:10.1007/978-3-319-78476-2_23
Kintu-Luwaga, R., Makumbi, T., Kilyewala, C., & Fualal, J. O. (2018) · East and Central African journal of surgery · doi:10.4314/ecajs.v23i3.2
Letter to the editor in regards to fasting vs bedtime thyroxine ingestion
Hennessey, J. V. (2020) · Clinical Endocrinology · doi:10.1111/cen.14186
DEVELOPMENT AND IN VITRO CHARACTERIZATION OF POLYMER-BASED NASAL FORMULATIONS OF LEVOTHYROXINE
Esomchukwu, V.-B. O. (2020) · DalSpace (Dalhousie University)
The pharmacological management of hypothyroidism
Moolman, L. J. (2021) · South African General Practitioner · doi:10.36303/sagp.2021.2.2.0070
Luíz, H. V., Manita, I., & Portugal, J. (2016) · Springer eBooks · doi:10.1007/978-3-319-25871-3_7
(2018) · American Journal of Psychiatry · doi:10.1176/appi.ajp.2018.1757correction4
(2015) · Elsevier eBooks · doi:10.1016/b978-0-444-53717-1.01544-4
7 Medical Management of Thyroiditis and Hypothyroidism
(2021) · Thieme Medical Publishers eBooks · doi:10.1055/b-0041-182782
Replacement Therapy for Hypothyroidism: Purpose and Indication for Correction
Степановна, М. Н., Алексеевич, Т. А., Matveyeva, Y. О., Олеговна, Щ. А., Кузина, И. А., Валерьевна, Г. Е., Эдуардовна, Т. М., & Petunina, N. A. (2024) · Effective Pharmacotherapy · doi:10.33978/2307-3586-2024-20-8-64-69
Thyroid and Parathyroid Transplantation
Sakr, M. F. (2024) · Springer eBooks · doi:10.1007/978-3-031-64102-2_18
Schilddrüsenfunktionsstörungen erkennen und behandeln
Wüster, C. C. (2025) · Journal für Gynäkologische Endokrinologie/Schweiz · doi:10.1007/s41975-025-00388-9
Food-Drug Interactions: Navigating the Complex Relationship
Ewis, D. K., & El-Sayed, O. S. (2025) · Nutritional neurosciences · doi:10.1007/978-981-95-1983-5_14
The Role of Nursing and Pharmacy in Enhancing Daily Medication Adherence Among Thyroid Patients
Almutlaq Ahlam Mohammed, T., ALSAADI, M. H., ALRUWAILI, M. M. A., Alanazı, K. N. K., Alenezı, A. A. N., ALRUWAILI, F. T. A., ALRUWAILI, M. N. J., ALENEZI, M. M. K., ALSALEEM, A. T., Alanazi, A. R. S., et al. (2024) · International Journal of Computational and Experimental Science and Engineering · doi:10.22399/ijcesen.3947
“Others may be deterred by the stringent administration requirements—taking L-T4 on an empty stomach with water, waiting 30-60 minutes before eating or drinking anything else, and avoiding concomitant medications and specific supplements like calcium and iron that impair absorption [5].”
Houshmand, F., Anjomshoa, M., Najafi-Chaleshtori, S., Mobini, G., Zafarian, R., Heidari, M., & Azizi, F. (2026) · Neurochemical Research · doi:10.1007/s11064-025-04650-1
Alamoudi, R. M., Nawar, S. M., Almulla, A. K., Alharbi, H. S., Alqarni, A., Alzahrani, A., Busaad, W. T., Alahmari, N. F. A., Alshamrani, N. D., Alkhalifa, L., et al. (2026) · Endocrine Practice · doi:10.1016/j.eprac.2026.01.008
Refractory hypothyroidism: Diagnostic evaluation and management strategies
Mavromati, M., Jarlborg, P., Demarchi, M. S., & Leboulleux, S. (2026) · Annales d Endocrinologie · doi:10.1016/j.ando.2026.102489 · Cited by 1
Farhan, M., Patel, T., Obais, M. A.-H. N., Taslimi, H., Hanif, M., Khalid, K., Qaqour, A., Waisi, J., Khalid, H., Husain, A. H. A. A., et al. (2026) · World Journal of Clinical Cases · doi:10.12998/wjcc.v14.i16.119700
Hennessey, J. V. (2026) · Clinical Thyroidology · doi:10.1177/23299711261425099
Metadata
- Authors
- Bach-Huynh, T.-G., Nayak, B., Loh, J., Soldin, S., & Jonklaas, J.
- Affiliations
- Georgetown University Medical Center (US)
- Corresponding author
- Jonklaas, Jacqueline
- ORCID
- Jonklaas, Jacqueline
- Venue
- The Journal of Clinical Endocrinology & Metabolism
- Publisher
- The Endocrine Society
- Published
- 2009-10-01
- Volume
- 94
- Issue
- 10
- Pages
- 3905-3912
- ISSN
- 0021-972X (ISSN-L)
- 1945-7197
- PMC
- PMC2758731
- OpenAlex
- W2110073453
- Cited by
- 198
- References
- 30
- Citations by year
- 2026: 5 · 2025: 10 · 2024: 10 · 2023: 7 · 2022: 14 · 2021: 13 · 2020: 11 · 2019: 11 · 2018: 19 · 2017: 10 · 2016: 21 · 2015: 16 · 2014: 12 · 2013: 11 · 2012: 14
- FWCI
- 6.80
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Deutsches Krebsforschungszentrum
- National Center for Research Resources (K23 RR16524, M01RR020359, MO1-RR-020359, K23RR016524)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
- Health Sciences › Medicine › Surgery › Thyroid and Parathyroid Surgery
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Cancer Diagnosis and Treatment
- Keywords
- levothyroxine, timing of drug administration, serum thyrotropin, thyroid-stimulating hormone, dietary intake, fasting, hypothyroidism, thyroid cancer, free thyroxine, total T3, drug absorption
- MeSH terms
- Administration, Oral, Adult, Aged, Drug Administration Schedule, Fasting, Female, Humans, Hypothyroidism, Male, Middle Aged, Thyroid Hormones, Thyroid Neoplasms, Thyrotropin, Thyroxine, Time Factors, Cross-Over Studies, Hormone Replacement Therapy
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.
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 ›
Are you an author, or do you see a problem with this page? Request a review
