Around two in five men with type 2 diabetes have borderline or low levels of testosterone, which can lead to decreased libido, loss of muscle mass, and increased fat around the waist [1].
Having type 2 diabetes makes testosterone deficiency twice as likely [2] – but why? We explore the link between the two conditions and the potential effects of testosterone replacement therapy (TRT) on blood sugar control.
Contents
- What’s the link between diabetes and testosterone?
- Does low testosterone cause diabetes?
- Can high testosterone cause diabetes?
- Can you take TRT with diabetes?
- Should I be on TRT if I have diabetes?
What’s the link between diabetes and testosterone?
People often associate testosterone with sex drive, sperm production, and muscle mass. While this is true, it has many other important functions. Testosterone affects bone mass, mood, energy levels, red blood cell production, and how the body controls blood sugar levels and distributes fat.
The body can store fat under the skin as subcutaneous fat, or around the organs as visceral fat. Having low testosterone levels is linked to higher levels of visceral fat, which increases the risk of insulin resistance and type 2 diabetes [1].
Low testosterone levels are thought to directly affect the insulin signalling pathways that allow glucose to be taken up by the cells. [3]. Also, high blood sugar levels (hyperglycaemia), as seen with diabetes, trigger the release of pro-inflammatory substances which can disrupt hormone levels, including testosterone [4].
There’s a clear link between low testosterone, insulin resistance, and type 2 diabetes. It’s likely due to testosterone’s effect on body composition and glucose signalling pathways, and the pro-inflammatory state of diabetes affecting hormone regulation.
Does low testosterone cause diabetes?
Low testosterone doesn’t necessarily cause type 2 diabetes, but it can certainly increase your risk of developing the condition. This is especially true if you have other risk factors for type 2 diabetes.
Likewise, men with diabetes are more likely to have testosterone deficiency, partly because testosterone levels are influenced by insulin resistance [5].
Can high testosterone cause diabetes?
For men, having higher levels of testosterone is linked with a lower risk of diabetes. But this isn’t the case for women.
A study of over 425,000 participants showed that having higher levels of testosterone significantly increased the risk of type 2 diabetes in women, as well as increased visceral fat storage and polycystic ovary syndrome [6].
Can you take TRT with diabetes?
Absolutely. If you're eligible, TRT is fine to use if you also have diabetes. More than that, it may actually help manage your diabetes.
Research shows that TRT can significantly improve blood sugar control, fasting insulin, and HbA1c in people with low testosterone and diabetes [7,8]. TRT is also likely to reduce the risk of mortality in this group [9]. Although evidence is mixed, some studies have also shown it can improve the balance of cholesterol and triglycerides [10].
Long-term TRT can also prevent prediabetes (borderline diabetes) from progressing into type 2 diabetes [8,11]. A study of 316 men found that men taking TRT did not go on to develop type 2 diabetes, but over 40% of men in the untreated group did [11].
Despite its positive effects, TRT isn’t for everyone and can come with side effects. The decision will ultimately come down to how much low testosterone impacts your quality of life.
Should I be on TRT if I have diabetes?
Whether or not you should be on TRT will depend on several factors including:
- Your testosterone level – TRT is usually considered a treatment option if your testosterone levels are less than 12 nmol/L. For men with prediabetes, the threshold increases to 14 nmol/L, because there’s evidence that TRT can prevent the progression of prediabetes to diabetes. Higher thresholds may be considered if your symptoms are strongly suggestive of testosterone deficiency.
- Your symptoms – If your symptoms of testosterone deficiency are mild, you may not see as big a benefit from TRT. Some men are able to improve their symptoms through lifestyle changes. However, this might be less effective for someone with severe symptoms.
- Any current conditions – TRT isn’t suitable for some people, including men who want to have children or men with prostate cancer, breast cancer, or severe heart failure.
Navigating low testosterone and diabetes
TRT shows promise in improving blood sugar control for men with diabetes and testosterone deficiency, but it’s important to weigh up the benefits against any potential side effects.
References
- Testosterone and Diabetes - Role, Diabetes Link in Men & Women. [cited 31 May 2024]. Available: https://www.diabetes.co.uk/body/testosterone-and-diabetes.html
- Low Testosterone | ADA. [cited 31 May 2024]. Available: https://diabetes.org/health-wellness/sexual-health/low-testosterone
- Pal M, Khan J, Kumar R, Surolia A, Gupta S. Testosterone supplementation improves insulin responsiveness in HFD fed male T2DM mice and potentiates insulin signaling in the skeletal muscle and C2C12 myocyte cell line. PLoS One. 2019;14: e0224162. doi:10.1371/journal.pone.0224162
- Cai T, Hu Y, Ding B, Yan R, Liu B, Cai L, et al. Effect of Metformin on Testosterone Levels in Male Patients With Type 2 Diabetes Mellitus Treated With Insulin. Front Endocrinol (Lausanne). 2021;12: 813067. doi:10.3389/fendo.2021.813067
- Grossmann M, Thomas MC, Panagiotopoulos S, Sharpe K, Macisaac RJ, Clarke S, et al. Low testosterone levels are common and associated with insulin resistance in men with diabetes. J Clin Endocrinol Metab. 2008;93: 1834–1840. doi:10.1210/jc.2007-2177
- Ruth KS, Day FR, Tyrrell J, Thompson DJ, Wood AR, Mahajan A, et al. Using human genetics to understand the disease impacts of testosterone in men and women. Nat Med. 2020;26: 252–258. doi:10.1038/s41591-020-0751-5
- Zhang J, Yang B, Xiao W, Li X, Li H. Effects of testosterone supplement treatment in hypogonadal adult males with T2DM: a meta-analysis and systematic review. World J Urol. 2018;36: 1315–1326. doi:10.1007/s00345-018-2256-0
- Wittert G, Bracken K, Robledo KP, Grossmann M, Yeap BB, Handelsman DJ, et al. Testosterone treatment to prevent or revert type 2 diabetes in men enrolled in a lifestyle programme (T4DM): a randomised, double-blind, placebo-controlled, 2-year, phase 3b trial. Lancet Diabetes Endocrinol. 2021;9: 32–45. doi:10.1016/S2213-8587(20)30367-3
- Hackett G, Cole N, Mulay A, Strange RC, Ramachandran S. Long-term testosterone therapy in type 2 diabetes is associated with reduced mortality without improvement in conventional cardiovascular risk factors. BJU Int. 2019;123: 519–529. doi:10.1111/bju.14536
- Kumari K, Kumar R, Memon A, Kumari B, Tehrim M, Kumari P, et al. Treatment with Testosterone Therapy in Type 2 Diabetic Hypogonadal Adult Males: A Systematic Review and Meta-Analysis. Clin Pract. 2023;13: 454–469. doi:10.3390/clinpract13020041
- Yassin A, Haider A, Haider KS, Caliber M, Doros G, Saad F, et al. Testosterone Therapy in Men With Hypogonadism Prevents Progression From Prediabetes to Type 2 Diabetes: Eight-Year Data From a Registry Study. Diabetes Care. 2019;42: 1104–1111. doi:10.2337/dc18-2388
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