A handful of herbs have shown genuine ability to raise testosterone levels in clinical trials, though the effects are modest compared to medical testosterone therapy. Ashwagandha has the strongest evidence, with one well-designed study showing a 14.7% increase in testosterone over eight weeks. Other herbs like fenugreek and tongkat ali have promising but less consistent data, and several popular options, including tribulus terrestris, don’t hold up under scrutiny at all.
Here’s what the research actually supports, what’s overhyped, and what to watch out for.
Ashwagandha: The Strongest Evidence
Ashwagandha is the most well-studied herb for testosterone, and the results are genuinely encouraging. In a randomized, double-blind, placebo-controlled crossover study published in the American Journal of Men’s Health, overweight men aged 40 to 70 who took ashwagandha for eight weeks saw a 14.7% greater increase in testosterone compared to placebo. They also had 18% higher levels of DHEA-S, a precursor hormone the body uses to make testosterone.
One common claim about ashwagandha is that it works by lowering cortisol, the stress hormone, which theoretically frees up the body’s resources for testosterone production. The data doesn’t fully support that narrative. In the same study, cortisol dropped by only 7.8% compared to placebo, and that difference wasn’t statistically significant. So while ashwagandha clearly does something to boost testosterone, the exact mechanism isn’t as simple as “lower stress, higher testosterone.”
Most clinical trials use a standardized extract (often labeled KSM-66) at doses around 600 mg per day. Raw ashwagandha powder is less studied and likely less potent gram for gram.
Tongkat Ali: Raises Free Testosterone
Tongkat ali (Eurycoma longifolia) is widely used in Southeast Asian traditional medicine and has real clinical data behind it. A study in young healthy males found significant increases in both total testosterone and free testosterone after supplementation. Free testosterone is the portion that’s actually available for your body to use, so this distinction matters.
Interestingly, the study found no changes in luteinizing hormone or follicle-stimulating hormone, the two signals your brain sends to tell your testes to produce testosterone. This suggests tongkat ali doesn’t work by ramping up that brain-to-testes signaling pathway. Instead, it may act more directly on the testes themselves or influence how much testosterone gets bound up by carrier proteins in the blood. The study also found a significant reduction in estradiol, a form of estrogen, which could partly explain the shift in hormonal balance.
Fenugreek: Modest, Dose-Dependent Effects
Fenugreek seed extract has been tested in several trials, and the results are real but uneven. In a 12-week double-blind study, men taking fenugreek extract saw a 13% increase in total plasma testosterone and a 16.3% increase in free testosterone index compared to their own baseline. However, when compared directly to placebo, the differences shrank and didn’t always reach statistical significance, which is a critical distinction. At the highest dose tested (1,800 mg per day), the free testosterone index was 12.2% higher than placebo, and that result was statistically significant.
The pattern here is dose-dependent: higher amounts produced more consistent results. Fenugreek likely works through compounds called furostanolic saponins, which may inhibit enzymes that convert testosterone into estrogen. If you’re considering fenugreek, lower doses found in many commercial blends may not be enough to produce a meaningful effect.
Ginger: Promising Mechanisms, Limited Human Data
Ginger has a surprisingly long list of biological pathways that could support testosterone production. Research has identified several mechanisms: it increases luteinizing hormone (the brain’s signal to produce testosterone), raises cholesterol availability in the testes (cholesterol is the raw material for making testosterone), reduces oxidative damage to testicular tissue, improves blood flow to the cells that produce testosterone, and may even help recycle testosterone receptors so the hormone gets used more efficiently.
The catch is that most of this research comes from animal studies. While the biological logic is sound, and ginger is safe and widely consumed, there isn’t a large body of controlled human trials confirming a specific percentage increase in testosterone. It’s a reasonable addition to your diet but shouldn’t be your primary strategy.
Tribulus Terrestris: Popular but Ineffective
Tribulus terrestris is one of the most marketed “testosterone boosters” on the supplement shelf, and it’s also one of the biggest disappointments in the research. A systematic review of ten clinical trials found that eight of them showed no significant change in testosterone after supplementation. Healthy men, young athletes, and trained CrossFit participants all saw zero meaningful effect at doses of 400 to 750 mg per day over two to three months.
The only two studies that found a testosterone increase involved men who already had clinically low levels (below 350 ng/dL), and even then, the increase was only about 60 to 70 ng/dL, a small bump in absolute terms. Those studies also had significant methodological limitations. If your testosterone is in the normal range, tribulus is unlikely to move the needle. Save your money.
Fadogia Agrestis: Unproven and Potentially Harmful
Fadogia agrestis gained popularity after being promoted on several high-profile podcasts, but the evidence behind it is thin and concerning. There are no published human clinical trials. The available research consists of rat studies, and those studies actually found signs of testicular toxicity, including elevated markers of tissue damage and disrupted testicular function at higher doses.
At the lowest dose tested (equivalent to traditional folk medicine use), rats did recover from the adverse effects, suggesting the toxicity may not be permanent at that level. But “probably not permanently toxic at the lowest dose in rats” is a far cry from “safe and effective in humans.” Until human safety data exists, this herb carries real risk with no proven reward.
Cistanche Tubulosa: Early-Stage Research
Cistanche tubulosa is a desert plant used in traditional Chinese medicine that has shown an interesting mechanism in laboratory research. Its active compounds appear to upregulate two key enzymes involved in testosterone production within the Leydig cells of the testes, essentially increasing the cellular machinery that converts cholesterol into testosterone. Animal studies have shown improved reproductive function through this pathway.
This is still early-stage research, though. The mechanism is biologically plausible and the initial data is positive, but well-controlled human trials are lacking. It’s worth watching but not worth building a supplement regimen around yet.
What the Medical Community Says
Major medical bodies remain cautious about herbal approaches to low testosterone. The Endocrine Society and the U.S. FDA recommend testosterone replacement therapy only for “classic” or irreversible testosterone deficiency, not for the gradual decline that comes with aging. This leaves a gap: many men with mildly low or borderline testosterone don’t qualify for medical treatment but still want options. That gap is exactly where herbal supplements have found their market.
A systematic review examining the overall evidence for testosterone-boosting herbs concluded that many commercially available supplements making these claims are not supported by scientific evidence, and that specific recommendations should be made cautiously. The herbs with the best data, primarily ashwagandha and tongkat ali, show real but modest effects that would not replace medical therapy for someone with clinically low testosterone.
Safety Considerations
Even herbs that effectively raise testosterone can carry risks, particularly for people on certain medications. Anything that influences hormone levels can potentially affect cardiovascular health. The FDA has warned that elevated testosterone, whether from medical therapy or other sources, is associated with increased blood pressure and a possible elevated risk of heart attack and stroke.
If you take blood pressure medication, blood thinners, or diabetes drugs, be aware that several of these herbs can interact with those medications. Ashwagandha may lower blood sugar and blood pressure on its own, which could amplify the effects of your existing medications. Fenugreek has similar blood-sugar-lowering properties. Ginger can have mild blood-thinning effects. None of these interactions are guaranteed to cause problems, but stacking herbs on top of existing prescriptions without awareness is where people get into trouble.
The supplement industry is also loosely regulated, meaning the dose on the label doesn’t always match what’s in the bottle. Choosing products that have been third-party tested helps reduce the risk of contamination or mislabeling.