A handful of supplements have genuine evidence behind them for raising testosterone, but the effects depend heavily on whether you’re deficient in a particular nutrient to begin with. If your levels of zinc, vitamin D, or magnesium are already normal, topping them off with extra supplements is unlikely to move the needle much. The supplements with the strongest research tend to work by correcting a deficiency or by subtly shifting how your body metabolizes the testosterone it already produces.
Ashwagandha
Ashwagandha is one of the more consistently supported options. In a randomized, double-blind, placebo-controlled crossover study of aging, overweight men, eight weeks of supplementation with a standardized root extract produced a 14.7% greater increase in testosterone and an 18% greater increase in DHEA-S (a precursor hormone) compared to placebo. Both results were statistically significant. Interestingly, while ashwagandha is often marketed as a cortisol-lowering supplement, this particular trial found no significant reduction in cortisol or estradiol. The testosterone bump appears to be a direct hormonal effect rather than a downstream result of stress reduction.
Zinc
Zinc is essential for testosterone production, and clinical studies on zinc-deprived men have shown that both testosterone synthesis and sperm production depend on adequate dietary zinc. The catch is the word “adequate.” If you’re already getting enough zinc through food (red meat, shellfish, legumes), supplementing more won’t push testosterone higher. In a study of men with low hormone levels who were already receiving medical treatment, adding zinc supplementation on top of that treatment produced no additional increase in serum testosterone compared to the treatment alone, as long as zinc levels were above the normal threshold.
Where zinc matters most is if you’re at risk of deficiency. Vegetarians, heavy sweaters, people who drink alcohol regularly, and older adults are more likely to run low. If that describes you, correcting the deficiency can meaningfully restore testosterone to its normal range.
Vitamin D
Vitamin D receptors exist throughout the male reproductive system, which is why researchers have long suspected a connection to testosterone. A systematic review found a weak but positive correlation between vitamin D levels and total testosterone, especially in men who were deficient or insufficient. The problem is that once researchers adjusted for age, body weight, and the time of day testosterone was measured, the relationship got weaker. And the evidence for vitamin D supplementation directly raising testosterone was inconclusive, with limited proof of significant changes in total testosterone.
That said, if your vitamin D levels are genuinely low (common if you live at a northern latitude, work indoors, or have darker skin), correcting the deficiency supports overall hormonal health even if the testosterone-specific effect is modest. It’s one of those supplements that’s worth taking for broader reasons, with a possible hormonal benefit as a bonus rather than the main event.
Fenugreek
Fenugreek seed extract works through a different mechanism than most nutrient-based supplements. Compounds in fenugreek are thought to inhibit two enzymes that convert testosterone into other hormones: one that converts it to estrogen and another that converts it to dihydrotestosterone. By slowing those conversions, more testosterone stays in its free, bioavailable form.
In a double-blind, placebo-controlled trial of healthy men doing resistance training for eight weeks, the group taking a fenugreek glycoside extract saw free testosterone rise 98.7% from baseline, compared to a 48.8% rise in the placebo group. Both groups were lifting weights, which itself raises testosterone, but the fenugreek group saw a significantly larger increase. These are promising numbers, though the study was small and described as a pilot, so the magnitude of effect may not hold up in larger trials.
Magnesium
Magnesium supplementation raised both free and total testosterone in a study comparing athletes to sedentary men. The increases showed up in both groups, but they were larger in the men who exercised. This makes magnesium particularly relevant if you’re physically active, since intense training depletes magnesium through sweat and increased metabolic demand. Like zinc, the benefit is most pronounced when you’re not getting enough from your diet. Good food sources include nuts, seeds, dark leafy greens, and whole grains, but many adults still fall short of the recommended daily intake.
Boron
Boron is a trace mineral that gets less attention than zinc or magnesium but has some intriguing data. In a small study of healthy men, just one week of supplementation at 6 mg per day raised free testosterone from an average of 11.83 pg/mL to 15.18 pg/mL, a roughly 28% increase. At the same time, estrogen levels dropped significantly, from 42.33 pg/mL to 25.81 pg/mL. The ratios of free testosterone to estrogen and free testosterone to total testosterone both improved substantially, suggesting boron helps shift the hormonal balance toward more bioavailable testosterone.
About 98% of the testosterone in your blood is bound to proteins and can’t be used by your cells. Boron appears to increase the proportion that circulates freely. This could be especially relevant for older men, whose levels of binding proteins tend to rise with age while free testosterone drops. The study was small (eight men), so the findings need replication, but the effect size was notable.
D-Aspartic Acid
D-aspartic acid (DAA) became popular after a study showed a 42% increase in testosterone after 12 days of supplementation. But context matters: the men in that study started with testosterone near the bottom of the normal clinical range. When researchers tested the same dose in resistance-trained men whose testosterone was already near the top of the normal range, 28 days of supplementation had zero effect on total testosterone, free testosterone, or any related hormone.
A systematic review concluded that DAA enhances testosterone in animal studies, while human results are inconsistent. A third study in overweight men with low baseline testosterone also failed to show significant changes after 14 or 28 days, which complicates the theory that DAA only works when levels are low. The overall picture is that DAA is unreliable. It might help a narrow subset of men with low baseline levels, but the evidence is too mixed to recommend it with confidence.
Tongkat Ali
Tongkat ali (Eurycoma longifolia) is widely marketed as a testosterone booster, with traditional doses ranging from 100 to 400 mg daily and some commercial products pushing 1,000 to 1,600 mg. However, in a controlled crossover study of 13 healthy male recreational athletes taking 400 mg daily for six weeks, there was no change in testosterone-to-epitestosterone ratio and no changes in liver or kidney markers. The evidence for tongkat ali raising testosterone in otherwise healthy men is thin.
Safety Concerns Worth Knowing
Most individual nutrients like zinc, magnesium, vitamin D, and boron are safe at recommended doses. The real risk comes from proprietary blends and multi-ingredient “testosterone booster” products sold online, which may contain undisclosed compounds or doses far beyond what’s been studied. Liver injury from these products is a documented concern. In one published case, a man developed acute liver injury after using a testosterone booster supplement for six months. His liver function only improved after he stopped taking it. The supplement industry is loosely regulated, and hepatotoxicity from these products is considered largely underreported.
If you’re choosing individual, well-studied supplements at researched doses, the risk profile is much lower than grabbing a proprietary stack off a shelf. Stick with products that list exact doses of each ingredient, and be skeptical of anything promising dramatic hormonal changes. The supplements with real evidence behind them produce modest effects, typically restoring levels to their normal range rather than pushing them beyond it.