Localization of human thyroxine absorption
Abstract
The distribution of intestinal absorption of 131I-labeled thyroxine (T4*) was studied in 4 normal subjects after oral and i.v. T4*, given in separate experimental sessions. In addition to collection of time-activity curves for plasma T4* from the two sessions, distribution and transport of T4* through the gut was quantified by external imaging. Time-activity curves were obtained for the stomach, duodenum, and upper jejunoileum. A multicompartmental model for systemic T4, with three distribution compartments and a single exit route, was employed. Additional, gastrointestinal, compartments were introduced. The stomach data were fitted to a model with three compartments, two for transport and a small sink of gastric activity that does not interact with the absorptive sites. Transfer from the duodenum to the upper jejunoileum and from the upper to the lower jejunoileum was modeled from fits to the peak T4* activities in the images of the duodenum and upper jejunoileum. The rate of transfer from the lower jejunoileum into more distal intestinal sites was fixed, but the impact on the results of using various values for this parameter was analyzed. The model calculations of absorption (mean +/- SD for 3 of the subjects) are duodenum, 15 +/- 5%, upper jejunoileum, 29 +/- 14%, and lower jejunoileum, 24 +/- 11%. The fourth subject, whose global absorption was abnormally low for uncertain reasons, had 17% absorption from the duodenum, 9% from the upper jejunoileum and none from the lower jejunoileum. Model projections mimicking clinical gut abnormalities known to affect T4 absorption were compatible with the results of published studies.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
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?
Absorption of LT4 occurs in the jejunum and ileum.
“Absorption of LT4 occurs in the jejunum and ileum (118).”
From Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement (2014) · cites this paper as [118]
Optimal absorption of LT4 is under fasting conditions, with 62-82% of dose absorbed during first 3 h after ingestion.
“The optimal absorption of LT4 is under fasting conditions, with 62–82% of the dose absorbed during the first 3 h after ingestion (45).”
From ETA guidelines for the use of levothyroxine sodium preparations in monotherapy to optimize the treatment of hypothyroidism (2025) · cites this paper as [45]
Absorption of oral thyroxine (T4) occurs predominantly in the jejunum and ileum.
“the absorption of oral thyroxine (T4) occurs predominantly in the jejunum and ileum (45)”
From ETA guidelines for the use of levothyroxine sodium preparations in monotherapy to optimize the treatment of hypothyroidism (2025) · cites this paper as [45]
In humans, the jejuno-ileal tract is the main site of oral thyroxine absorption.
“In humans, the jejuno-ileal tract is the main site of oral thyroxine absorption while duodenum absorbs a few parts, but nothing has been reported to be absorbed in the large bowel unlike in the rats (Hays, 1988; Hays, 1991).”
From Thyroid disorders and gastrointestinal dysmotility: an old association (2024) · cites this paper as Hays, 1991
In humans, no oral thyroxine absorption has been reported in the large bowel, unlike in rats.
“In humans, the jejuno-ileal tract is the main site of oral thyroxine absorption while duodenum absorbs a few parts, but nothing has been reported to be absorbed in the large bowel unlike in the rats (Hays, 1988; Hays, 1991).”
From Thyroid disorders and gastrointestinal dysmotility: an old association (2024) · cites this paper as Hays, 1991
Levothyroxine is not completely absorbed orally; approximately 70% of an administered oral dose is absorbed.
“Levothyroxine is not completely absorbed orally with only 70% of the dose administered is reported to be absorbed (Hays, 1991).”
From Thyroid disorders and gastrointestinal dysmotility: an old association (2024) · cites this paper as Hays, 1991
After ingestion in the fasting state, LT4 absorption rapidly increases and reaches a maximum at 1.5 to 2 hours.
“After ingestion in the fasting state, absorption rapidly increases and reaches a maximum at 1.5 to 2 hours (19).”
From Levothyroxine: conventional and novel drug delivery formulations. (2023) · cites this paper as [19]
The small intestine is proposed to be the predominant site for LT4 absorption, as no uptake of LT4 was detected in a patient with no jejunum or ileum.
“As no uptake of LT4 was detected in a patient with no jejunum or ileum (19), the small intestine is proposed to be the predominant site for LT4 absorption.”
From Levothyroxine: conventional and novel drug delivery formulations. (2023) · cites this paper as [19]
In patients with celiac disease, intestinal parasitosis, or other intestinal dysfunctions, TSH concentrations remained elevated even after treatment with increased doses.
“In patients with celiac disease, intestinal parasitosis, or other intestinal dysfunctions, TSH concentrations remained elevated, even after treatment with increased doses (19, 23–26).”
From Levothyroxine: conventional and novel drug delivery formulations. (2023) · cites this paper as [19]
Oral LT4 dissolves in the stomach at low pH but is absorbed mainly in the small intestine (jejunum and ilium) within three hours of ingestion.
“Oral LT4 (typically formulated as the sodium salt) dissolves in the stomach at low pH but is absorbed mainly in the small intestine (the jejunum and ilium) within three hours of ingestion [ 14 , 15 ].”
From Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults (2022) · cites this paper as [15]
Cites
The Routine Fitting of Kinetic Data to Models
Berman, M., Shahn, E., & Weiss, M. F. (1962) · Biophysical Journal · doi:10.1016/s0006-3495(62)86855-6 · Cited by 335 · see citing works
Variability of motility of the ileum and jejunum in healthy humans
Kerlin, P., & Phillips, S. F. (1982) · Gastroenterology · doi:10.1016/0016-5085(82)90313-4 · Cited by 169 · see citing works
Caride, V. J., Prokop, E. K., Troncale, F. J., Buddoura, W., Winchenbach, K., & McCallum, R. W. (1984) · Gastroenterology · doi:10.1016/s0016-5085(84)80121-3 · Cited by 132 · see citing works
DiStefano, J. J., JANG, M., MALONE, T. K., & Broutman, M. A. (1982) · Endocrinology · doi:10.1210/endo-110-1-198 · Cited by 120 · see citing works
Hays, M. T. (1988) · Endocrine Research · doi:10.3109/07435808809032986 · Cited by 94 · see citing works
L-Thyroxine Absorption in Patients with Short Bowel
STONE, E., LEITER, L. A., LAMBERT, J. R., SILVERBERG, J. D. H., JEEJEEBHOY, K. N., & BURROW, G. N. (1984) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem-59-1-139 · Cited by 66 · see citing works
Malabsorption of Thyroid Hormones After Jejunoileal Bypass for Obesity
AZIZI, F., BELUR, R., & ALBANO, J. (1979) · Annals of Internal Medicine · doi:10.7326/0003-4819-90-6-941 · Cited by 61 · see citing works
Thyroxine malabsorption following intestinal bypass surgery.
Js, B., & Jf, M. (1986) · PubMed · Cited by 51 · see citing works
Transport of the Thyroid Hormones Across the Feline Gut Wall
Hays, M. T., HSU, L., & Kohatsu, S. (1992) · Thyroid · doi:10.1089/thy.1992.2.45 · Cited by 18 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Jonklaas, J., Bianco, A. C., Bauer, A. J., Burman, K. D., Cappola, A. R., Celi, F. S., Cooper, D. S., Kim, B. W., Peeters, R. P., Rosenthal, M. S., et al. (2014) · Thyroid® · doi:10.1089/thy.2014.0028 · Cited by 1,928 · see citing works
“Absorption of LT4 occurs in the jejunum and ileum (118).”
Kaptein, E. M., Hays, M. T., & Ferguson, D. C. (1994) · Veterinary Clinics of North America Small Animal Practice · doi:10.1016/s0195-5616(94)50051-2 · Cited by 267 · see citing works
Scientific Opinion on Dietary Reference Values for iodine
EFSA Panel on Dietetic Products, N. A. A. (. (2014) · EFSA Journal · doi:10.2903/j.efsa.2014.3660 · Cited by 267 · see citing works
Treatment with thyroid hormone
Biondi, B., & Wartofsky, L. (2014) · Endocrine Reviews · doi:10.1210/er.2013-1083 · Cited by 259 · see citing works
Thyroid-hormone therapy and thyroid cancer: a reassessment
Biondi, B., Filetti, S., & Schlumberger, M. J. (2005) · Nature Clinical Practice Endocrinology & Metabolism · doi:10.1038/ncpendmet0020 · Cited by 221 · see citing works
Effect of calcium carbonate on the absorption of levothyroxine
Singh, N. (2000) · JAMA · doi:10.1001/jama.283.21.2822 · Cited by 219 · see citing works
Timing of levothyroxine administration affects serum thyrotropin concentration
Bach-Huynh, T.-G., Nayak, B., Loh, J., Soldin, S., & Jonklaas, J. (2009) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2009-0860 · Cited by 198 · see citing works
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 · see citing works
A review of the pharmacokinetics of levothyroxine for the treatment of hypothyroidism
Colucci, P., Yue, C. S., Ducharme, M., Benvenga, S., Principal Scientist, L. A. C. I., Principal Scientist, L. A. C. I. A. P. C., President and CEO, L. A. C. I., & Professor of Medicine, D. (2010) · European Endocrinology · doi:10.17925/ee.2013.09.01.40 · Cited by 167 · see citing works
Gastrointestinal malabsorption of thyroxine
Virili, C., Antonelli, A., Santaguida, M. G., Benvenga, S., & Centanni, M. (2019) · Endocrine Reviews · doi:10.1210/er.2018-00168 · Cited by 164 · see citing works
Burch, H. B. (2019) · New England Journal of Medicine · doi:10.1056/nejmra1901214 · Cited by 164 · see citing works
Delayed 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 · see citing works
Drugs affecting thyroid function
Barbesino, G. (2010) · Thyroid · doi:10.1089/thy.2010.1635 · Cited by 146 · see citing works
Liel, Y., Harman-Boehm, I., & Shany, S. (1996) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jcem.81.2.8636317 · Cited by 129 · see citing works
Pabla, D., Akhlaghi, F., & Zia, H. (2009) · European Journal of Pharmaceutics and Biopharmaceutics · doi:10.1016/j.ejpb.2008.10.008 · Cited by 124 · see citing works
Hashimoto’s Thyroiditis and Autoimmune Gastritis
Cellini, M., Santaguida, M. G., Virili, C., Capriello, S., Brusca, N., Gargano, L., & Centanni, M. (2017) · Frontiers in Endocrinology · doi:10.3389/fendo.2017.00092 · Cited by 120 · see citing works
Hypothyroidism in the Elderly: Pathophysiology, Diagnosis and Treatment
Laurberg, P., Andersen, S., Pedersen, I. B., & Carl, A. B. (2005) · Drugs & Aging · doi:10.2165/00002512-200522010-00002 · Cited by 141 · see citing works
Hypothyroidism and Thyroiditis
Brent, G. A., & Davies, T. F. (2011) · Elsevier eBooks · doi:10.1016/b978-1-4377-0324-5.00013-4 · Cited by 115 · see citing works
Atypical celiac disease as cause of increased need for thyroxine: a systematic study
Virili, C., Bassotti, G., Santaguida, M. G., Iuorio, R., Del Duca, S. C., Mercuri, V., Picarelli, A., Gargiulo, P., Gargano, L., & Centanni, M. (2012) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2011-1851 · Cited by 114 · see citing works
Vita, R., Saraceno, G., Trimarchi, F., & Benvenga, S. (2014) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2014-2684 · Cited by 99 · see citing works
Bolk, N., Visser, T. J., Kalsbeek, A., van Domburg, R. T., & Berghout, A. (2006) · Clinical Endocrinology · doi:10.1111/j.1365-2265.2006.02681.x · Cited by 96 · see citing works
The administration of l -thyroxine as soft gel capsule or liquid solution
Vita, R., Fallahi, P., Antonelli, A., & Benvenga, S. (2014) · Expert Opinion on Drug Delivery · doi:10.1517/17425247.2014.918101 · Cited by 93 · see citing works
Controversies in the Management of Low-Risk Differentiated Thyroid Cancer
Haymart, M. R., Esfandiari, N. H., Stang, M. T., & Sosa, J. A. (2017) · Endocrine Reviews · doi:10.1210/er.2017-00067 · Cited by 79 · see citing works
The Acute Effect of Calcium Carbonate on the Intestinal Absorption of Levothyroxine
Singh, N., Weisler, S. L., & Hershman, J. M. (2001) · Thyroid · doi:10.1089/105072501753211046 · Cited by 77 · see citing works
Diagnosis and treatment of levothyroxine pseudomalabsorption.
Lips, D. J., Reisen, M. V., Voigt, V., & Venekamp, W. J. R. R. (2004) · PubMed · Cited by 73 · see citing works
Systematic appraisal of lactose intolerance as cause of increased need for oral thyroxine
Cellini, M., Santaguida, M. G., Gatto, I., Virili, C., Del Duca, S. C., Brusca, N., Capriello, S., Gargano, L., & Centanni, M. (2014) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/jc.2014-1217 · Cited by 72 · see citing works
Human Thyroxine Absorption: Age Effects and Methodological Analyses
HAYS, M. T., & NIELSEN, K. R. K. (1994) · Thyroid · doi:10.1089/thy.1994.4.55 · Cited by 67 · see citing works
Thyroxine softgel capsule in patients with gastric-related T4 malabsorption
Santaguida, M. G., Virili, C., Duca, S. C. D., Cellini, M., Gatto, I., Brusca, N., De Vito, C., Gargano, L., & Centanni, M. (2015) · Endocrine · doi:10.1007/s12020-014-0476-7 · Cited by 68 · see citing works
Serum Thyrotropin Levels Following Levothyroxine Administration at Breakfast
Perez, C. L. S., Araki, F. S., Graf, H., & de Carvalho, G. A. (2013) · Thyroid · doi:10.1089/thy.2012.0435 · Cited by 63 · see citing works
New Formulations of Levothyroxine in the Treatment of Hypothyroidism: Trick or Treat?
Nagy, E. V., Perros, P., Papini, E., Katkó, M., & Hegedűs, L. D. (2020) · Thyroid · doi:10.1089/thy.2020.0515 · Cited by 65 · see citing works
Levothyroxine: conventional and novel drug delivery formulations.
Liu, H., Li, W., Zhang, W., Sun, S., & Chen, C. (2023) · Endocrine Reviews · doi:10.1210/endrev/bnac030 · Cited by 63 · see citing works
Improved Levothyroxine Pharmacokinetics After Bariatric Surgery
Gkotsina, M., Michalaki, M., Mamali, I., Markantes, G., Sakellaropoulos, G. C., Kalfarentzos, F., Vagenakis, A. G., & Markou, K. B. (2013) · Thyroid · doi:10.1089/thy.2011.0526 · Cited by 57 · see citing works
Rubio, I. G. S., Galrão, A. L., Santo, M. A., Zanini, A. C., & Medeiros-Neto, G. (2012) · Obesity Surgery · doi:10.1007/s11695-011-0452-8 · Cited by 58 · see citing works
Doki, K., Darwich, A. S., Patel, N. K., & Rostami‐Hodjegan, A. (2017) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2017.07.035 · Cited by 56 · see citing works
Caron, P., Grunenwald, S., Persani, L., Borson-Chazot, F., Leroy, R., & Duntas, L. (2022) · Reviews in Endocrine and Metabolic Disorders · doi:10.1007/s11154-021-09691-9 · Cited by 53 · see citing works
Helicobacter pyloriinfection and drugs malabsorption
Lahner, E. (2014) · World Journal of Gastroenterology · doi:10.3748/wjg.v20.i30.10331 · Cited by 53 · see citing works
Rajput, R., Chatterjee, S., & Rajput, M. (2011) · Journal of Thyroid Research · doi:10.4061/2011/505239 · Cited by 52 · see citing works
Levothyroxine therapy in gastric malabsorptive disorders
Virili, C., Brusca, N., Capriello, S., & Centanni, M. (2021) · Frontiers in Endocrinology · doi:10.3389/fendo.2020.621616 · Cited by 52 · see citing works
Fierabracci, P., Martinelli, S., Tamberi, A., Piaggi, P., Basolo, A., Pelosini, C., Ricco, I., Magno, S., Querci, G., Ceccarini, G., et al. (2016) · Thyroid · doi:10.1089/thy.2015.0473 · Cited by 51 · see citing works
Fallahi, P., Ferrari, S. M., Ruffilli, I., Ragusa, F., Biricotti, M., Materazzi, G., Miccoli, P., & Antonelli, A. (2016) · Expert Opinion on Drug Delivery · doi:10.1080/17425247.2016.1227782 · Cited by 48 · see citing works
Pabla, D., Akhlaghi, F., & Zia, H. (2010) · European Journal of Pharmaceutical Sciences · doi:10.1016/j.ejps.2010.05.002 · Cited by 47 · see citing works
Brancato, D., Scorsone, A., Saura, G., Ferrara, L., Di Noto, A., Aiello, V., Fleres, M., & Provenzano, V. (2014) · Endocrine Practice · doi:10.4158/ep13418.or · Cited by 44 · see citing works
Thyroid disorders and gastrointestinal dysmotility: an old association
Xu, G.-M., Hu, M.-X., Li, S.-Y., Ran, X., Zhang, H., & Ding, X.-F. (2024) · Frontiers in Physiology · doi:10.3389/fphys.2024.1389113 · Cited by 43 · see citing works
Oral levothyroxine therapy postbariatric surgery: Biopharmaceutical aspects and clinical effects
Azran, C., Porat, D., Fine‐Shamir, N., Hanhan, N., & Dahan, A. (2019) · Surgery for Obesity and Related Diseases · doi:10.1016/j.soard.2019.01.001 · Cited by 42 · see citing works
Novel thyroxine formulations: a further step toward precision medicine
Virili, C., Trimboli, P., & Centanni, M. (2019) · Endocrine · doi:10.1007/s12020-019-02049-x · Cited by 41 · see citing works
de Carvalho, G. A., Paz-Filho, G., Mesa, C. O., & Graf, H. (2018) · European Journal of Endocrinology · doi:10.1530/eje-17-0947 · Cited by 41 · see citing works
Azran, C., Hanhan-Shamshoum, N., Irshied, T., Ben-Shushan, T., Dicker, D., Dahan, A., & Matok, I. (2021) · Surgery for Obesity and Related Diseases · doi:10.1016/j.soard.2021.02.028 · Cited by 40 · see citing works
Gluvic, Z. M., Obradovic, M. M., Stewart, A. J., Essack, M., Pitt, S. J., Samardzic, V. S., Šoškić, S., Gojobori, T., & Isenović, E. R. (2021) · Frontiers in Endocrinology · doi:10.3389/fendo.2021.758043 · Cited by 39 · see citing works
Levothyroxine dosing following bariatric surgery
Gadiraju, S., Lee, C. J., & Cooper, D. S. (2016) · Obesity Surgery · doi:10.1007/s11695-016-2314-x · Cited by 39 · see citing works
Levothyroxine absorption test to differentiate pseudomalabsorption from true malabsorption
Ghosh, S., Pramanik, S., Biswas, K., Bhattacharjee, K., Sarkar, R., Chowdhury, S., & Mukhopadhyay, P. (2020) · European Thyroid Journal · doi:10.1159/000504218 · Cited by 39 · see citing works
Unusual malabsorption of levothyroxine
Jauk, B., Mikosch, P., Gallowitsch, H. J., Kresnik, E., Molnar, M., Gomez, I., & Lind, P. (2000) · Thyroid · doi:10.1089/thy.2000.10.93 · Cited by 34 · see citing works
Impaired Pharmacokinetics of Levothyroxine in Severely Obese Volunteers
Michalaki, M. A., Gkotsina, M. I., Mamali, I., Markantes, G. K., Faltaka, A., Kalfarentzos, F., Vagenakis, A. G., & Markou, K. B. (2011) · Thyroid · doi:10.1089/thy.2010.0149 · Cited by 34 · see citing works
Centanni, M., Duntas, L., Feldt-Rasmussen, U., Koehrle, J., Peeters, R. P., Razvi, S., Trimboli, P., & Virili, C. (2025) · European Thyroid Journal · doi:10.1530/etj-25-0123 · Cited by 38 · see citing works
“The optimal absorption of LT4 is under fasting conditions, with 62 – 82% of the dose absorbed during the fi rst 3 h after ingestion (45).”
Tanguay, M., Girard, J., Scarsi, C., Mautone, G., & Larouche, R. (2019) · Clinical Pharmacology in Drug Development · doi:10.1002/cpdd.608 · Cited by 33 · see citing works
Van Wilder, N., Bravenboer, B., Herremans, S., Vanderbruggen, N., & Velkeniers, B. (2017) · European Thyroid Journal · doi:10.1159/000452489 · Cited by 31 · see citing works
Timing of breakfast does not influence therapeutic efficacy of liquid levothyroxine formulation
Morelli, S., Reboldi, G., Moretti, S., Menicali, E., Avenia, N., & Puxeddu, E. (2016) · Endocrine · doi:10.1007/s12020-015-0788-2 · Cited by 30 · see citing works
Care of the Patient After Metabolic and Bariatric Surgery
Bramante, C., Wise, E., & Chaudhry, Z. (2022) · Annals of Internal Medicine · doi:10.7326/aitc202205170 · Cited by 28 · see citing works
Different formulations of levothyroxine for treating hypothyroidism: a real-life study
Trimboli, P., Scappaticcio, L., De Bellis, A., Maiorino, M. I., Knappe, L., Esposito, K., Bellastella, G., & Giovanella, L. (2020) · International Journal of Endocrinology · doi:10.1155/2020/4524759 · Cited by 27 · see citing works
Quantifying Amount of Adsorption of Levothyroxine by Percutaneous Endoscopic Gastrostomy Tubes
Manessis, A., Lascher, S., Bukberg, P. R., Darmody, T., Yen, V., Sadek, S., & Young, I. S. (2008) · Journal of Parenteral and Enteral Nutrition · doi:10.1177/0148607108314770 · Cited by 24 · see citing works
Tablet formulation of levothyroxine is absorbed less well than powdered levothyroxine
Yamamoto, T. (2003) · Thyroid · doi:10.1089/10507250360731596 · Cited by 21 · see citing works
Lombardi, C. P., Bocale, R., Barini, A., Barini, A., D’Amore, A., Boscherini, M., & Bellantone, R. (2017) · Endocrine · doi:10.1007/s12020-016-1003-9 · Cited by 23 · see citing works
Clinical Relevancy of the Levothyroxine–Continuous Enteral Nutrition Interaction
Dickerson, R. N., Maish, G. O., Minard, G., & Brown, R. O. (2010) · Nutrition in Clinical Practice · doi:10.1177/0884533610385701 · Cited by 23 · see citing works
Levothyroxine treatment and gastric juice pH in humans: the proof of concept
Virili, C., Bruno, G., Santaguida, M. G., Gargano, L., Stramazzo, I., De Vito, C., Cicenia, A., Scalese, G., Porowska, B., Severi, C., et al. (2022) · Endocrine · doi:10.1007/s12020-022-03056-1 · Cited by 22 · see citing works
Trimboli, P., Virili, C., Centanni, M., & Giovanella, L. (2018) · Frontiers in Endocrinology · doi:10.3389/fendo.2018.00118 · Cited by 21 · see citing works
Ulcerative colitis as a novel cause of increased need for levothyroxine
Virili, C., Stramazzo, I., Santaguida, M. G., Bruno, G., Brusca, N., Capriello, S., Cellini, M., Severi, C., Gargano, L., & Centanni, M. (2019) · Frontiers in Endocrinology · doi:10.3389/fendo.2019.00233 · Cited by 20 · see citing works
Guglielmi, V., Bellia, A., Bianchini, E., Medea, G., Cricelli, I., Sbraccia, P., Lauro, D., Cricelli, C. A., & Lapi, F. (2017) · Endocrine · doi:10.1007/s12020-017-1412-4 · Cited by 20 · see citing works
The use of levothyroxine absorption tests in clinical practice
Caron, P., & Declèves, X. (2023) · The Journal of Clinical Endocrinology & Metabolism · doi:10.1210/clinem/dgad132 · Cited by 18 · see citing works
Raza, S., Ishtiaq, O., Unnikrishnan, A., Khan, A. A., Ahmad, J., Ganie, M., Azad, K., Baruah, M. P., & Pathan, M. F. (2012) · Indian Journal of Endocrinology and Metabolism · doi:10.4103/2230-8210.98001 · Cited by 18 · see citing works
Alternative routes of levothyroxine administration for hypothyroidism
Ritter, M. J., Gupta, S., & Hennessey, J. V. (2020) · Current Opinion in Endocrinology, Diabetes & Obesity · doi:10.1097/med.0000000000000558 · Cited by 18 · see citing works
Chen, S., Yu, M., Yao, Y., Li, Y., He, A., Zhou, Z., Pan, L., Xiao, N., Luo, H., & Sun, H. (2024) · Environment & Health · doi:10.1021/envhealth.3c00184 · Cited by 18 · see citing works
Calcium Carbonate–Induced Hypothyroidism
Butner, L. E., Fulco, P. P., & Feldman, G. (2000) · Annals of Internal Medicine · doi:10.7326/0003-4819-132-7-200004040-00026 · Cited by 17 · see citing works
The performance of levothyroxine tablet is impaired by bariatric surgery
Trimboli, P., Ossola, N., Torre, A., Mongelli, F., Quarenghi, M., Camponovo, C., Lucchini, B., Rotondi, M., Ruinelli, L., & Garofalo, F. (2022) · Endocrine · doi:10.1007/s12020-022-03289-0 · Cited by 17 · see citing works
Levothyroxine absorption test results in patients with TSH elevation resistant to treatment
Yildirim Simsir, I., Soyaltin, U. E., & Ozgen, A. G. (2019) · Endocrine · doi:10.1007/s12020-019-01889-x · Cited by 16 · see citing works
Administration and pharmacokinetics of levothyroxine
Lipp, H.-P. (2021) · 70 Years of Levothyroxine · doi:10.1007/978-3-030-63277-9_2 · Cited by 18 · see citing works
Hypothyroidism and Thyroiditis
Brent, G. A., & Weetman, A. P. (2016) · Elsevier eBooks · doi:10.1016/b978-0-323-29738-7.00013-7 · Cited by 16 · see citing works
Levothyroxine dose adjustment in hypothyroid patients following gastric sleeve surgery
Richou, M., Gilly, O., Taillard, V., Brauwere, D. P. D., Donici, I., & Guedj, A. M. (2020) · Annales d Endocrinologie · doi:10.1016/j.ando.2020.04.011 · Cited by 16 · see citing works
Managing symptoms in hypothyroid patients on adequate levothyroxine: a narrative review
Razvi, S., Mrabeti, S., & Luster, M. (2020) · Endocrine Connections · doi:10.1530/ec-20-0205 · Cited by 15 · see citing works
“LT4 is absorbed via the intestine, and intestinal disorders may influence the absorption of LT4 and thus the dosage required to control the TSH level [80].”
BackgroundInterference with the absorption of levothyroxine
Singh, N. K., & Hershman, J. M. (2003) · Current Opinion in Endocrinology & Diabetes · doi:10.1097/00060793-200310000-00008 · Cited by 15 · see citing works
DiStefano, J. J., Nguyen, T. T., & Yen, Y. M. (1992) · Endocrinology · doi:10.1210/en.131.1.275 · Cited by 15 · see citing works
EMPATHY: A New Tool for Identifying the Most Suitable Thyroxine Formulation in Hypothyroid Patients
Bellastella, G., Caputo, M., Maiorino, M. I., Longo, M., Scappaticcio, L., Giugliano, D., & Esposito, K. (2019) · Thyroid · doi:10.1089/thy.2018.0493 · Cited by 14 · see citing works
Tortora, A., La Sala, D., & Vitale, M. (2019) · Endocrinology, Diabetes & Metabolism Case Reports · doi:10.1530/edm-19-0026 · Cited by 13 · see citing works
Severe hypothyroidism in patients dependent on prolonged thyroxine infusion through a jejunostomy
Smyrniotis, V., Vaos, N., Arkadopoulos, N., Kostopanagiotou, G., Theodoraki, K., & Lambrou, A. (2000) · Clinical Nutrition · doi:10.1054/clnu.1999.0087 · Cited by 13 · see citing works
Should the dose of levothyroxine be changed in hypothyroidism patients fasting during Ramadan?
Koca, A. O., Dağdeviren, M., & Altay, M. (2020) · TURKISH JOURNAL OF MEDICAL SCIENCES · doi:10.3906/sag-1911-28 · Cited by 13 · see citing works
Change in levothyroxine requirements after bariatric surgery in patients with hypothyroidism
García‐Moreno, R. M., Cos-Blanco, A. I., Viñuela, I. C., Zapatero-Larrauri, M., & Herranz, L. (2022) · Endocrine Regulations · doi:10.2478/enr-2022-0009 · Cited by 11 · see citing works
Reversible hypothyroidism and Whipple's disease
Tran, H. A. (2006) · BMC Endocrine Disorders · doi:10.1186/1472-6823-6-3 · Cited by 10 · see citing works
Kocic, I., Homšek, I., Dačević, M., Cvijić, S., Parojčić, J., Vučićević, K. M., Prostran, M. S., & Miljković, B. (2012) · Biopharmaceutics & Drug Disposition · doi:10.1002/bdd.1780 · Cited by 10 · see citing works
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 · see citing works
Oteri, 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 · see citing works
A curious case of refractory hypothyroidism due to selective malabsorption of oral thyroxine
Damle, N., Bal, C., Soundararajan, R., Kumar, P., & Durgapal, P. (2012) · Indian Journal of Endocrinology and Metabolism · doi:10.4103/2230-8210.95716 · Cited by 9 · see citing works
Daily requirement of softgel thyroxine is independent from gastric juice pH
Virili, C., Capriello, S., Stramazzo, I., Brusca, N., Santaguida, M. G., Gargano, L., Bagaglini, M. F., Bruno, G., Severi, C., & Centanni, M. (2022) · Frontiers in Endocrinology · doi:10.3389/fendo.2022.1002583 · Cited by 8 · see citing works
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 · see citing works
Jojima, T., Shinzawa, T., Ohira, E., Sakurai, S., Tomaru, T., Iijima, T., Kogai, T., Usui, I., & Aso, Y. (2022) · Endocrine Journal · doi:10.1507/endocrj.ej21-0656 · Cited by 6 · see citing works
Therapeutic options in systemic AL amyloidosis.
Gameren, I. I. V., Lokhorst, H. M., Hazenberg, B. P. C., & Vellenga, E. (2004) · PubMed · Cited by 6 · see citing works
Decreased expression of ileal thyroid hormone transporters in a hypothyroid patient: a case report
Chung, C. W., Mo, E. Y., Jung, G. S., Kim, Y. H., Cho, S. W., Park, D. J., Bae, J. M., & Park, Y. J. (2021) · Frontiers in Endocrinology · doi:10.3389/fendo.2021.664839 · Cited by 5 · see citing works
“Although most ileal absorption of oral LT4 occurs at jejunum and ileum (28), it was impossible to obtain specimens from those areas in the case patient because endoscopic biopsy is limited to stomach, duodenum, and colon.”
BackgroundA dose of paracetamol for the levothyroxine absorption test
Thynne, T., & Doogue, M. P. (2013) · Clinical Endocrinology · doi:10.1111/cen.12211 · Cited by 5 · see citing works
Hypothyroidism during pregnancy.
Nava‐Ocampo, A. A., Soldin, O. P., & Koren, G. (2004) · PubMed Central · Cited by 5 · see citing works
Levothyroxine absorption test—results and follow up of patients from a single center
Subramaniam, K., Babu, T., Sreevalsan, K. C., & Mathew, S. (2023) · Indian Journal of Endocrinology and Metabolism · doi:10.4103/ijem.ijem_188_21 · Cited by 4 · see citing works
Diagnosis and Treatment of Hypothyroidism
Ashraff, S., & Razvi, S. (2018) · Endocrinology · doi:10.1007/978-3-319-45013-1_14 · Cited by 4 · see citing works
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 · see citing works
An Unusual Cause of Refractory Hypothyroidism
Mirgoli, O. J., Ramjas, V., Munugoti, S., Silverstein, H., Malik, F., Salem, A., Cassavell, F., & Atoot, A. (2022) · Cureus · doi:10.7759/cureus.23522 · Cited by 4 · see citing works
- Authors
- HAYS, M. T.
- Affiliations
- VA Palo Alto Health Care System (US)
- Corresponding author
- HAYS, MARGUERITE T.
- Venue
- Thyroid
- Publisher
- SAGE Publications
- Published
- 1991-01
- Volume
- 1
- Issue
- 3
- Pages
- 241-248
- ISSN
- 1050-7256 (ISSN-L)
- 1557-9077
- OpenAlex
- W2087473356
- Cited by
- 138
- References
- 9
- Citations by year
- 2026: 1 · 2025: 9 · 2024: 6 · 2023: 5 · 2022: 10 · 2021: 6 · 2020: 7 · 2019: 11 · 2018: 7 · 2017: 8 · 2016: 9 · 2015: 2 · 2014: 8 · 2013: 4 · 2012: 5
- FWCI
- 1.15
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Thyroid (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Thyroid Disorders and Treatments
- Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Radiopharmaceutical Chemistry and Applications
- Life Sciences › Pharmacology, Toxicology and Pharmaceutics › Pharmaceutical Science › Drug Solubulity and Delivery Systems
- Keywords
- intestinal absorption, duodenum, stomach, multi-compartment model, time-activity curves, oral versus intravenous administration, thyroid hormone absorption
- MeSH terms
- Administration, Oral, Adult, Duodenum, Female, Gastric Mucosa, Gastrointestinal Transit, Humans, Injections, Intravenous, Intestinal Absorption, Intestinal Mucosa, Jejunum, Male, Middle Aged, Models, Biological, Thyroxine, Time Factors
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
