From the Guidelines
Testosterone replacement therapy (TRT) can potentially affect Hemoglobin A1c (HbA1c) levels, and its impact varies based on individual factors, including baseline metabolic health and dosage. The relationship between testosterone and blood sugar is complex, and while TRT may improve insulin sensitivity and lower HbA1c in some men with low testosterone, it may increase HbA1c levels in others, particularly those predisposed to diabetes or metabolic issues 1. According to the most recent and highest quality study, the American College of Physicians guidance statement on HbA1c targets for glycemic control with pharmacologic therapy in nonpregnant adults with type 2 diabetes mellitus, published in 2024, clinicians should aim to achieve an HbA1c level between 7% and 8% in most patients with type 2 diabetes 1.
Key Considerations
- The effect of TRT on HbA1c levels can vary based on the individual's baseline metabolic health, dosage, and administration method (injections, gels, patches) 1.
- Regular monitoring of HbA1c levels is important, especially during the first 3-6 months of treatment, to assess the impact of TRT on blood sugar control 1.
- If HbA1c levels rise while on TRT, adjustments to the testosterone dosage or the addition of lifestyle modifications may help manage blood sugar levels while continuing necessary hormone replacement 1.
- Clinicians should consider deintensifying pharmacologic therapy in patients with type 2 diabetes who achieve HbA1c levels less than 6.5%, as the benefits of more intensive glycemic control may not outweigh the harms 1.
Clinical Implications
- Clinicians should personalize goals for glycemic control in patients with type 2 diabetes, taking into account the benefits and harms of pharmacotherapy, patient preferences, and individual factors such as life expectancy and comorbid conditions 1.
- The American College of Physicians recommends aiming for an HbA1c level between 7% and 8% in most patients with type 2 diabetes, and considering deintensifying pharmacologic therapy in patients who achieve HbA1c levels less than 6.5% 1.
From the FDA Drug Label
In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, insulin requirements
- The FDA drug label suggests that testosterone replacement therapy may affect blood glucose levels in diabetic patients, which could indirectly impact Hemoglobin A1c (HbA1c) levels.
- However, it does not directly state the effect of testosterone replacement therapy on HbA1c levels.
- Based on the available information, it can be inferred that testosterone replacement therapy may have an indirect effect on HbA1c levels by decreasing blood glucose levels in diabetic patients 2.
From the Research
Effect of Testosterone Replacement Therapy on HbA1c Levels
- Testosterone replacement therapy (TRT) has been shown to have varying effects on Hemoglobin A1c (HbA1c) levels in men with type 2 diabetes and androgen deficiency 3, 4, 5, 6, 7.
- A study published in the European journal of medical research found that TRT decreased HbA1c levels in men with type 2 diabetes and androgen deficiency, with the best results obtained in the treatment group 3.
- In contrast, a study published in Diabetes care found that testosterone therapy did not improve glycemic control, as measured by HbA1c, in men with type 2 diabetes and lowered testosterone 4.
- Another study published in Andrology found that the association between TRT and change in HbA1c differed between subgroups of men with type 2 diabetes and adult-onset testosterone deficiency, with some subgroups showing a significant association between TRT and improved HbA1c levels 5.
- A study published in The aging male found that TRT resulted in a reduction of HbA1c by 0.94% points in obese hypogonadal diabetic males 6.
- A study published in The journal of sexual medicine found that TRT produced a statistically significant reduction in HbA1c at 6 and 18 weeks, with the most marked reduction in poorly controlled patients with baseline HbA1c greater than 7.5 7.
Factors Influencing the Effect of TRT on HbA1c Levels
- Baseline sex hormone-binding globulin (SHBG) levels and age may identify clinical subgroups that respond differently to TRT 5.
- The presence of depression may influence the response to TRT, with improvements in HbA1c levels being less marked in men with depression at baseline 7.
- Achieving adequate serum levels of testosterone may be related to improvements in HbA1c levels 7.