Men with diabetes can technically purchase over-the-counter testosterone boosters, but whether those supplements will do anything meaningful is a different question. The overlap between diabetes and low testosterone is striking: roughly 35 to 50 percent of men with type 2 diabetes have testosterone levels below the normal range, compared with far lower rates in men without diabetes. That connection makes testosterone-boosting products appealing, but the evidence behind most supplements is thin, and the stakes for someone managing blood sugar are higher than for the general population.
Why Diabetes and Low Testosterone Travel Together
The link between type 2 diabetes and low testosterone is well established and unusually common. One large study found that 43 percent of men with type 2 diabetes had reduced total testosterone, and 57 percent had reduced free testosterone, with both measures strongly tied to insulin resistance.1The Journal of Clinical Endocrinology & Metabolism. Low Testosterone Levels Are Common and Associated with Insulin Resistance in Men with Diabetes Another cross-sectional study put the number at about 37 percent of diabetic men having total testosterone below 3 ng/mL, with 80 percent of those men reporting symptoms of androgen deficiency like fatigue, low libido, and reduced muscle mass.2PubMed Central. Prevalence of low testosterone levels in men with type 2 diabetes mellitus: a cross-sectional study A case-control study in Ghana put the contrast even more starkly: about 71 percent of men with type 2 diabetes were hypogonadal, compared with 25 percent of non-diabetic men.3PLOS Global Public Health. Prevalence and determinants of low testosterone levels in men with type 2 diabetes mellitus; a case-control study in a district hospital in Ghana
The relationship runs in both directions. Excess body fat, particularly visceral fat, converts testosterone into estrogen through an enzyme called aromatase, lowering circulating testosterone. At the same time, low testosterone promotes fat storage and worsens insulin resistance, creating a feedback loop. Research on this bidirectional relationship has shown that men with hypogonadal testosterone levels are about twice as insulin resistant as men with normal levels, and that the low testosterone itself appears to cause mitochondrial dysfunction that compounds the metabolic problem.4PubMed Central. Testosterone and Insulin Resistance in Men: Evidence for a Complex Bi-Directional Relationship The upshot is that low testosterone is not just a side effect of diabetes; it is an active participant in making the metabolic picture worse.5The Journal of Clinical Endocrinology & Metabolism. Low Testosterone in Men with Type 2 Diabetes: Significance and Treatment
What Most Over-the-Counter Testosterone Boosters Actually Deliver
Walk into any supplement store or search online and you will find dozens of products marketed as testosterone boosters. The labels promise more energy, bigger muscles, and higher testosterone. The reality is far less impressive. A review that examined the composition and marketing claims of commercially available testosterone-boosting supplements found that 90 percent of them claimed to boost testosterone, but only about 25 percent of those products had any published data showing they actually raised testosterone levels. Around 10 percent of the products had data showing they actually decreased testosterone, and about 18 percent showed no change at all.6PubMed Central. ‘Testosterone Boosting’ Supplements Composition and Claims Are not Supported by the Academic Literature The same review found that 13 of the products contained ingredient doses exceeding the upper limits set by the FDA for zinc, vitamin B3, or magnesium.
For someone with diabetes, the lack of quality control is a real concern beyond just wasted money. Supplements are not regulated the same way prescription drugs are. They do not go through the same testing for safety, purity, or interaction with other medications. If you are on metformin, insulin, or any other blood-sugar-lowering drug, adding an unregulated supplement with unknown ingredient doses introduces unpredictable variables into an already complex regimen.
Popular Ingredients and What the Evidence Says
A handful of ingredients show up repeatedly in testosterone-booster formulations. Some have genuine research behind them, though the studies tend to be small. Others are essentially useless for raising testosterone despite decades of marketing claims.
Fenugreek
Fenugreek is one of the better-studied ingredients in this category. A pilot study in men doing resistance training found that fenugreek glycoside supplementation led to a significant increase in free testosterone compared to placebo over eight weeks, though total testosterone did not change significantly in either group.7PubMed Central. Beneficial effects of fenugreek glycoside supplementation in male subjects during resistance training: A randomized controlled pilot study A clinical review covering multiple trials concluded that fenugreek extract elevated both total and free testosterone and improved sexual function in men.8medtigo Journal of Pharmacology. Fenugreek (Trigonella foenum-graecum) as a Natural Therapeutic Agent in Type 2 Diabetes, PCOS, and Testosterone Deficiency: A Consolidated Clinical Review
For people with diabetes specifically, fenugreek has an interesting dual profile. It has a long history of use as a blood-sugar-lowering agent in traditional medicine, and some clinical data supports modest effects on glucose. An animal study in diabetic rats found that fenugreek steroids lowered blood glucose while also boosting steroidogenesis enzymes in the testes, increasing testosterone and estradiol levels.9PubMed. Potential protective effect on key steroidogenesis and metabolic enzymes and sperm abnormalities by fenugreek steroids in testis and epididymis of surviving diabetic rats That dual effect on both glucose and testosterone makes it one of the more intriguing supplement ingredients for diabetic men, but the human evidence is still limited and the glucose-lowering effect means it could theoretically stack with your diabetes medications in ways that need watching.
Ashwagandha
Ashwagandha has gained popularity as an adaptogen, and its testosterone effects have been studied in a handful of trials. A randomized crossover study in overweight men aged 40 to 70 found that ashwagandha supplementation raised testosterone by about 15 percent compared to placebo.10PubMed Central. A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha (Withania somnifera) in Aging, Overweight Males A systematic review of ashwagandha’s effects in healthy adults found that it appeared to regulate hormone levels while also reducing markers of inflammation and oxidative stress.11PubMed Central. Effects of Withania somnifera (Ashwagandha) on Hematological and Biochemical Markers, Hormonal Behavior, and Oxidant Response in Healthy Adults: A Systematic Review The anti-inflammatory angle could be helpful for diabetic men, since chronic inflammation is part of the insulin-resistance landscape. But these studies were not conducted in diabetic populations, so we are extrapolating.
Zinc
Zinc is essential for testosterone production, and diabetes tends to deplete zinc levels. An animal study showed that zinc combined with metformin corrected zinc imbalances in the testes and improved testosterone synthesis in diabetic mice.12PubMed. Zinc Combined with Metformin Corrects Zinc Homeostasis and Improves Steroid Synthesis and Semen Quality in Male Type 2 Diabetic Mice by Activating PI3K/AKT/mTOR Pathway That is a mouse study, not a human trial, so the findings are preliminary. Still, correcting a genuine zinc deficiency is a straightforward nutritional intervention that your doctor can test for. The problem with supplement formulations is that some testosterone boosters contain zinc at doses well above the tolerable upper limit, which can cause copper deficiency and gastrointestinal problems over time.
Tribulus Terrestris
Tribulus terrestris is one of the most heavily marketed testosterone-boosting herbs. A systematic review of the evidence concluded that it is ineffective for increasing testosterone levels in humans, and that the marketing claims are not supported by the data.13PubMed. A systematic review on the herbal extract Tribulus terrestris and the roots of its putative aphrodisiac and performance enhancing effect If your testosterone booster lists tribulus as a headline ingredient, that is a red flag about whether the manufacturer is following the science or the marketing playbook.
D-Aspartic Acid
D-aspartic acid (DAA) shows up in many formulations as well. A systematic review found that while DAA raised testosterone levels in male animal studies, the human evidence was inconsistent.14PubMed Central. The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review Some human trials showed small increases, others showed no change, and at least one showed a decrease. Not the kind of evidence you would want to bet your metabolic health on.
How Prescription Testosterone Therapy Differs
The contrast between OTC boosters and prescription testosterone replacement therapy (TRT) is stark. Prescription TRT delivers actual testosterone in controlled, measured doses. For diabetic men with confirmed low testosterone, TRT has a much stronger evidence base, and some of the findings are directly relevant to diabetes management.
A systematic review and meta-analysis of TRT in men with type 2 diabetes and low testosterone found that it significantly reduced HbA1c, the standard measure of long-term blood sugar control.15PubMed Central. Treatment with Testosterone Therapy in Type 2 Diabetic Hypogonadal Adult Males: A Systematic Review and Meta-Analysis Individual trials have reported larger improvements. One study in obese hypogonadal men with type 2 diabetes found that TRT reduced HbA1c by nearly a full percentage point and substantially improved insulin resistance scores.16PubMed. The impact of testosterone replacement therapy on glycemic control, vascular function, and components of the metabolic syndrome in obese hypogonadal men with type 2 diabetes Other trials have shown TRT reducing visceral fat, improving waist-to-hip ratio, and lowering total body fat in diabetic men.17PubMed. Testosterone supplementation in men with type 2 diabetes, visceral obesity and partial androgen deficiency Those body composition changes feed back into better insulin sensitivity, creating a positive cycle rather than the vicious one that low testosterone and diabetes typically produce.
Adherence matters. A study tracking diabetic men on TRT found that only the group with greater than 75 percent adherence saw a meaningful drop in HbA1c, and that the improvement was linked to how much BMI changed alongside the testosterone treatment.18PubMed Central. Glycemic benefits with adherence to testosterone therapy in men with hypogonadism and type 2 diabetes mellitus TRT is not a quick fix; it works best as part of a broader metabolic strategy.
The Hypoglycemia Risk That Nobody Warns About
Here is where things get genuinely dangerous for diabetic men, whether they are on prescription TRT or experimenting with supplements that actually affect testosterone. Testosterone improves insulin sensitivity. That sounds like a good thing, and in the long run it is. But if you are already taking insulin or oral medications that lower blood sugar, an improvement in insulin sensitivity can cause your existing medication doses to become too strong, pushing blood sugar dangerously low.
A case report and review in the medical literature flagged that testosterone therapy may enhance the blood-sugar-lowering effect of diabetes medications, creating a higher risk of hypoglycemia when the two are used together. The authors noted that while the interaction between testosterone and insulin has been documented, very little is known about how testosterone interacts with oral medications like DPP-4 inhibitors, and they cautioned that hypoglycemic events should not be ruled out with any combination.19PubMed Central. Testosterone Replacement Therapy and the Risk of Hypoglycemia The practical implication is clear: if anything you take raises your testosterone or improves your insulin sensitivity, your diabetes medications may need to be adjusted downward. That adjustment requires monitoring and medical oversight, not guesswork.
Cardiovascular and Kidney Safety
For years, the biggest concern around testosterone therapy was heart risk. That question got a definitive answer from the TRAVERSE trial, the largest randomized study on the cardiovascular safety of TRT. In over 5,000 men with cardiovascular disease or high cardiovascular risk, testosterone treatment did not increase the rate of major cardiac events compared to placebo.20PubMed. Cardiovascular Safety of Testosterone-Replacement Therapy The trial did find higher rates of atrial fibrillation, acute kidney injury, and pulmonary embolism in the testosterone group, though the overall cardiac event rate was similar between groups. A follow-up review confirmed no increase in prostate cancer risk either.21PubMed Central. Long Term Cardiovascular Safety of Testosterone Therapy: A Review of the TRAVERSE Study
The kidney finding deserves attention for people with diabetes, since diabetic kidney disease is already one of the most common complications of poorly controlled blood sugar. Some research has suggested that testosterone could accelerate diabetic nephropathy by raising blood pressure or directly injuring kidney tubule cells.22ScienceDirect. Testosterone deficiency and chronic kidney disease If you already have reduced kidney function, this is a conversation to have with your doctor before starting any testosterone therapy, prescription or otherwise.
Weight Loss as a Testosterone Strategy
Before reaching for a supplement or a prescription, it is worth considering the most well-supported route to higher testosterone in diabetic men: losing weight. Research on the bidirectional relationship between testosterone and insulin resistance found that weight loss reversed hypogonadism in over half of obese men with impaired glucose tolerance.4PubMed Central. Testosterone and Insulin Resistance in Men: Evidence for a Complex Bi-Directional Relationship A review of weight loss and testosterone confirmed that fat reduction, whether through diet, exercise, or bariatric surgery, reliably raises testosterone levels. The effect works through reduced aromatase activity, improved insulin sensitivity, and lower inflammation.23PubMed Central. Impact of Weight Loss on Testosterone Levels: A Review of BMI and Testosterone Resistance training specifically improves hormonal profiles while also building muscle and improving glucose disposal.
This does not mean weight loss replaces medical treatment. But for a man with type 2 diabetes who suspects low testosterone, achieving even moderate fat loss often produces testosterone increases that no supplement on the shelf can match, while simultaneously improving the diabetes itself.
Type 1 Diabetes and Testosterone
Most of the research on testosterone and diabetes focuses on type 2, but type 1 diabetes is not immune to the problem. A case series of hypogonadal men with type 1 diabetes who received TRT showed improvements in blood sugar control, weight, waist circumference, and lipid profiles while on treatment, all of which deteriorated when TRT was temporarily stopped and improved again when it was resumed.24PubMed. Effects of long-term testosterone replacement therapy, with a temporary intermission, on glycemic control of nine hypogonadal men with type 1 diabetes mellitus – a series of case reports A randomized placebo-controlled study of testosterone undecanoate in men with type 1 diabetes and low testosterone found significant improvements in cholesterol, with total cholesterol and LDL dropping substantially compared to placebo, though insulin sensitivity and HbA1c did not change.25Endocrine Journal. Testosterone undecanoate improves lipid profile in patients with type 1 diabetes and hypogonadotrophic hypogonadism
The evidence base is much smaller for type 1 than for type 2 diabetes. But low testosterone does occur in men with type 1, and the lipid and body composition benefits appear to hold. The hypoglycemia risk is arguably even more pressing here, since people with type 1 diabetes rely entirely on exogenous insulin, leaving no endogenous buffer when insulin sensitivity improves.
Why the Hormonal Picture Is Bigger Than Just Testosterone
Evaluating testosterone in isolation can miss the forest for the trees. Testosterone interacts with other hormones, and several of those interactions matter when diabetes is in the picture. Pituitary and thyroid function both influence testosterone levels, and clinicians evaluating men for low testosterone should consider whether other hormonal abnormalities are contributing.26PubMed Central. Testosterone replacement therapy: role of pituitary and thyroid in diagnosis and treatment A study of normoglycemic men found that both cortisol and thyroid hormone correlated positively with testosterone, while beta-cell secretion and BMI correlated negatively with it.27PubMed. Plasma testosterone in adult normoglycaemic men: impact of hyperinsulinaemia
For someone with diabetes, this means a low testosterone reading might reflect thyroid dysfunction, high cortisol from chronic stress, or the insulin resistance itself rather than a primary problem with the testes. Treating just the testosterone without addressing the upstream cause can leave the real issue untouched. This is another reason why an OTC booster is a poor substitute for a proper evaluation: the supplement cannot tell you why your testosterone is low.
What About Women with Diabetes
The question of testosterone boosters typically gets framed around men, but women with diabetes also have hormonal considerations, and the picture looks quite different. A study of postmenopausal women found that three months of testosterone treatment induced insulin resistance and worsened cholesterol profiles, even as it increased lean body mass.28PubMed. Effects of treatment with testosterone alone or in combination with estrogen on insulin sensitivity in postmenopausal women That is roughly the opposite of what happens in men. For women with diabetes, testosterone supplementation could make blood sugar control harder, not easier. The metabolic effects of androgens are sex-dependent, and generalizing from the male literature to female patients would be a mistake.
Women with conditions like polycystic ovary syndrome already tend to have elevated androgens and insulin resistance running together. Adding more testosterone into that hormonal environment could compound both problems. If you are a woman with diabetes considering any product marketed to boost testosterone, the evidence warrants serious caution and a conversation with an endocrinologist rather than a trip to the supplement aisle.