Abstract
OBJECTIVE To investigate the effect of metformin on testosterone levels in men with type 2 diabetes mellitus (T2DM).
RESERCH DESIGN AND METHODS Seventy men with newly diagnosed drug-naive T2DM and HbA1c >9.0% (75 mmol/mol) were treated with intensive insulin pump therapy for 5 days to achieve glucose normalization. They were randomized to control (continued on intensive insulin only) and metformin (plus metformin) groups (1:1) for 1 month. Testosterone was measured at baseline, randomization, and after 1-month treatment.
RESULTS Total, free, and bioavailable testosterone increased significantly within 5 days (all P < 0.001). After 1 month, compared with the control group, the metformin group had lower total (12.7 vs. 15.3 nmol/L), free (0.20 vs. 0.24 nmol/L), and bioavailable (4.56 vs. 5.31 nmol/L) testosterone (all P < 0.05).
CONCLUSIONS In men with T2DM, 1-month oral metformin may decrease serum testosterone levels independent of blood glucose control. The effects of long-term metformin on testosterone in men need further study.
Footnotes
This article contains supplementary material online at https://doi.org/10.2337/figshare.13574474.
- Received June 24, 2020.
- Accepted January 11, 2021.
- © 2021 by the American Diabetes Association
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license.
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March 2021
Volume 44, Issue 3
