SynthesisScientific reports2023
The effect of metformin therapy on serum thyrotropin and free thyroxine concentrations in patients with type 2 diabetes: a meta-analysis.
Synthesis in Scientific reports, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers, 1 of them a synthesis that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
9 citing papers in PubMed, 1 synthesis or guideline pooled it, 12 citations in OpenAlex.
- Prevalence of subclinical hypothyroidism in polycystic ovary syndrome and its impact on insulin resistance: a systematic review and meta-analysis.BMC endocrine disorders · 2025Pooled it
- Endocrine-Metabolic Crosstalk Between Diabetes Mellitus and Hypothyroidism: From Network Mechanisms to Translational Stratification.FASEB journal : official publication of the Federation of American Societies for Experimental Biology · 2026Review
- Letter to the editor: Association between thyroid dysfunction and cognitive impairment in type 2 diabetes mellitus: A cross-sectional study.Journal of diabetes investigation · 2026Article
- Vitamin D Adequacy Conditions the Prolactin-Suppressive Effect of Metformin in Men Receiving Prolactin-Elevating Medications.Nutrients · 2026Article
- Article
- Metformin and Myo-Inositol: A Comparative Analysis.Gynecologic and obstetric investigation · 2026Review
- Effect of metformin treatment on ovarian function in hypothyroid rats.Open veterinary journal · 2026Article
- To study effects of metformin on thyroid functions in type-2 diabetes mellitus in patients attending OPD at Government Medical College, Bidar.Journal of family medicine and primary care · 2025Article
- A Critical Examination of Metformin Package Inserts and Summaries of Product Characteristics.Deutsches Arzteblatt international · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Type 2 diabetes and thyroid function disorders are two common chronic endocrine disorders with the high prevalence in various populations. Metformin is well established as the first-line drug therapy for managing diabetes mellitus. In this meta-analysis, we aimed to determine the effect of metformin on serum TSH and FT4 concentrations in patients with type 2 diabetes. We searched PubMed, Scopus, web of science, Cochrane library, and google scholar to collect information on the effect of metformin on serum TSH and FT4 levels. Demographic and clinical information and serum TSH and FT4 concentrations before and after metformin treatment were extracted. Studies on patients over 18 years of age were included. A total of 11 studies including 1147 patients were selected for the final analysis. In hypothyroid patients, the TSH level decreased significantly after treatment with metformin (Hedges's g:1.55, 95%CI 0.93-2.16, p-value < 0.001); FT4 level increased slightly after taking metformin, but the increase was not significant (Heddges's g: - 0.30, 95%CI - 0.90,0.31, p-value = 0.34). In euthyroid subjects, the slight decrease found in TSH and FT4 concentrations was not statistically significant. Metformin reduces TSH levels in hypothyroid patients; however, it has no effect on TSH levels in euthyroid patients. Metformin does not affect serum FT4 levels in euthyroid and hypothyroid patients.
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