Tribulus Is Sold as a Testosterone Booster. Eight of Ten Trials in Men Found No Change in Male Hormones, and the Erection Benefit It Does Show Arrives Without a Testosterone Rise.
Tribulus terrestris, a spiny weed also called puncture vine or gokshura, has been one of the standard ingredients in testosterone booster blends for decades. The label claim is simple: the plant's saponins, especially protodioscin, are said to push the body to make more testosterone, which then brings more drive, more muscle and better erections. The controlled trials in men tell a different story. Healthy young men given tribulus for four weeks had the same testosterone as men on placebo. Older men with erectile dysfunction did no better than placebo in one trial, but did better in a larger trial run with the manufacturer of a branded extract, and that improvement came without a matching rise in testosterone. This article goes through what each study measured, who was in it and what the safety reports show, so a man can judge the supplement on the data rather than the label.
Key Takeaways: What the Research Shows About Tribulus and Testosterone
In a 2005 Journal of Ethnopharmacology trial of 21 healthy men aged 20 to 36, four weeks of tribulus extract at 10 or 20 mg/kg a day left testosterone, LH and androstenedione no different from placebo. A 2025 systematic review in Nutrients found that 8 of 10 studies in 483 men reported no change in male hormones, and the 2 positive studies showed within-group rises of 60 to 70 ng/dL, both in men with hypogonadism. A 2024 systematic review of 52 studies on 27 testosterone boosters did not rate tribulus as effective for raising total testosterone in any group of men. For erectile function, a 2026 meta-analysis of 8 studies found tribulus beat placebo by 3.23 points on the IIEF-5 score, with no difference in testosterone between groups. The largest single trial, 180 men with mild or moderate erectile dysfunction, used a branded extract and included an author from the company that makes it. Case reports describe severe liver and kidney injury and a statin interaction that ended in rhabdomyolysis.
Four Weeks of Tribulus in Healthy Young Men
Mean serum testosterone (nmol/l) in 21 healthy men aged 20 to 36, seven per group, given 20 or 10 mg/kg of Tribulus terrestris extract a day or placebo for 4 weeks. None of the differences were significant, and LH and androstenedione did not change either (Neychev and Mitev, Journal of Ethnopharmacology, 2005).
What is Tribulus terrestris and why is it sold for testosterone?
Tribulus terrestris is a low-growing flowering plant whose fruit and leaves have been used in Ayurvedic and traditional Chinese medicine for urinary complaints and as a tonic. Supplement makers sell it as a testosterone booster because the plant contains steroidal saponins, particularly protodioscin, that some animal studies linked to higher androgen levels. The marketing grew from Bulgarian sports programs and from rat and primate studies in which tribulus extracts raised testosterone. A 2014 systematic review in the Journal of Dietary Supplements by Qureshi, Naughton and Petroczi at Kingston University traced that history. The review included 11 studies and found that a limited number of animal studies showed higher testosterone after tribulus. In humans, a rise appeared only when tribulus was one ingredient in a combined supplement, which makes it impossible to credit the plant. The authors concluded that tribulus is ineffective for raising testosterone in humans and that the marketing claims are unsubstantiated. They also suggested a nitric oxide effect on blood vessels as a more plausible explanation for any benefit men notice.
Does tribulus raise testosterone in healthy young men?
Tribulus did not raise testosterone in healthy young men in the cleanest early trial. Vladimir Neychev and Vasil Mitev at the Medical University of Sofia randomized 21 men aged 20 to 36 into three groups of seven: tribulus extract at 20 mg/kg a day, tribulus at 10 mg/kg a day, or placebo, split into three daily doses for 4 weeks. The researchers drew blood repeatedly over the four weeks. Mean testosterone was 15.75 nmol/l in the high-dose group, 16.32 nmol/l in the lower-dose group and 17.74 nmol/l on placebo, and none of these differences were significant. LH, the pituitary signal that tells the testes to make testosterone, and androstenedione, a precursor hormone, did not change either. All values stayed in the normal range. The Sofia study is small, with seven men per group, and it ran for four weeks. Its finding still matters because the doses were high and weight-adjusted. If tribulus pushed LH or testosterone up through the pituitary, the study design was suited to see it. The authors wrote that the saponins appeared to have neither direct nor indirect androgen-raising properties.
Four Weeks of Tribulus in Healthy Young Men
Mean serum testosterone (nmol/l) in 21 healthy men aged 20 to 36, seven per group, given 20 or 10 mg/kg of Tribulus terrestris extract a day or placebo for 4 weeks. None of the differences were significant, and LH and androstenedione did not change either (Neychev and Mitev, Journal of Ethnopharmacology, 2005).
Does tribulus help men who lift build strength or muscle?
Tribulus did not add strength or lean mass beyond training alone in the controlled trials of athletes. Rogerson and colleagues at Southern Cross University in Australia gave 22 elite rugby league players either 450 mg of tribulus extract or placebo once a day for 5 weeks of heavy preseason resistance training, with 11 players in each group. Strength and fat-free mass increased in both groups, with no difference between them. The authors noted that the supplement had been promoted as producing large strength and muscle gains in 5 to 28 days, and that the trial found no such effect. The urinary testosterone to epitestosterone ratio, which anti-doping labs use to flag testosterone use, also did not change and stayed far from the World Anti-Doping Agency limit of 4:1. A 2021 trial in Nutrients by Fernández-Lázaro and colleagues gave 770 mg of tribulus or placebo to 30 CrossFit-trained men for 6 weeks. That study was single-blind, meaning the researchers knew who got which capsule. Tribulus did not improve body composition or overall CrossFit performance, though the authors reported a significant group by time effect for testosterone and bench press. With 30 men and an unblinded research team, the testosterone signal is weak support at best.
What happened when men with erectile dysfunction took tribulus?
In men with erectile dysfunction, the trial results split, and the split tracks study size and sponsorship more than testosterone. Santos and colleagues at the State University of Campinas in Brazil randomized 30 men aged 40 or older with erectile dysfunction to 800 mg of tribulus a day or placebo for 30 days, 15 men per group. Mean total testosterone in the tribulus group went from 417.1 ng/dl to 409.3 ng/dl. In the placebo group it went from 442.7 ng/dl to 466.3 ng/dl. Erection scores on the IIEF-5 questionnaire rose in both groups, from 13.2 to 15.3 on tribulus and from 11.6 to 13.7 on placebo. Time alone produced a significant improvement, but the difference between the groups was not significant. The authors concluded that at this dose and duration tribulus was no better than placebo for either erections or testosterone. The Santos trial shows how strong the placebo response is in erectile dysfunction research. Men who join a trial, fill in questionnaires and expect help often score better a month later whatever capsule they took. Any trial of tribulus that lacks a placebo arm cannot separate the plant from that effect.
Testosterone Before and After 30 Days, Men With Erectile Dysfunction
Mean total testosterone (ng/dl) in 30 men aged 40 or older with erectile dysfunction, 15 per group, before and after 30 days of 800 mg Tribulus terrestris a day or placebo (Santos and colleagues, Actas Urologicas Espanolas, 2014).
- Before
- After 30 days
What did the largest tribulus trial for erections find?
The largest trial found a modest erection benefit and no clear role for testosterone. Zdravko Kamenov and colleagues in Sofia randomized 180 men aged 18 to 65 with mild or moderate erectile dysfunction, 90 to tribulus and 90 to placebo, for 12 weeks. Men with hypertension, diabetes and metabolic syndrome were allowed in. The extract was Tribestan, taken as 3×2 tablets of 250 mg a day, and 86 men in each group finished. The results were published in Maturitas in 2017. The IIEF score improved more on tribulus, with a difference of 2.70 points over placebo (95% CI 1.40 to 4.01). Intercourse satisfaction, orgasmic function, sexual desire and overall satisfaction also favored tribulus. Adverse events were no more common than on placebo. Two details shape how far the Kamenov result travels. The product was a single standardized brand, and one of the authors listed an affiliation with the Medical and Regulatory Affairs Department of Sopharma AD, the company that makes Tribestan. Industry-linked trials are not automatically wrong, but they need independent replication. The pooled data now point the same way: a 2026 meta-analysis in the International Journal of Impotence Research by Suharyani and colleagues combined 8 studies and found tribulus beat placebo on the IIEF-5 by 3.23 points (95% CI 1.89 to 4.58) and on the full IIEF-15 by 14.44 points, with no difference in total testosterone between groups and no difference in adverse events.
Erection Scores Rose in Both Groups
Mean IIEF-5 erectile function score before and after 30 days in the same 30-man trial. Both groups improved over time, and the difference between them was not significant (Santos and colleagues, Actas Urologicas Espanolas, 2014).
- Before
- After 30 days
Can tribulus raise testosterone in men with low levels?
The only studies showing a testosterone rise were small, in men who already had low testosterone, and largely without a proper comparison between groups. A 2016 pilot study from Cairo University by Roaiah and colleagues gave 750 mg a day to 30 men with partial androgen deficiency of the aging male for 3 months. Total and free testosterone and IIEF-5 scores rose, and LH did not change. The study had no control group. A 2019 Urologia trial from the same Cairo group, led by GamalEl Din, did include a placebo arm: 70 aging men with low testosterone, erectile dysfunction and urinary symptoms, 35 per group, for 3 months. Within the tribulus group, total testosterone went from 2.2 to 2.7 and IIEF-5 from 10.7 to 16.1. The abstract reports these as changes from baseline rather than as a comparison with placebo. AST, a liver enzyme, rose from 26.5 to 27.8, and PSA rose from 1.4 to 1.7. The 2025 Nutrients systematic review by Vilar Neto and colleagues summed up this pattern. Across 10 studies and 483 men, 8 found no change in male hormones. The 2 that did found within-group rises of 60 to 70 ng/dL, both in men with hypogonadism, which the reviewers called low clinical magnitude. Half of the studies scored as low methodological quality. The same Cairo group also tested 750 mg for three months in 30 men with unexplained infertility and found no change in testosterone, LH or semen parameters.
What Ten Tribulus Studies in Men Found for Testosterone
Of 10 studies (483 men aged 16 to 70) in a 2025 systematic review, 8 reported no significant change in androgens. The 2 that did found within-group rises of 60 to 70 ng/dL, both in men with hypogonadism (Vilar Neto and colleagues, Nutrients, 2025).
- No change in androgens
- Within-group testosterone rise
If testosterone does not rise, why might erections improve?
The most supported explanation is an effect on blood vessels rather than on hormones. Neychev and Mitev returned to the question in a 2016 review in the Journal of Ethnopharmacology that covered literature from 1968 to 2015. They concluded that the evidence for an androgen mechanism was at best inconclusive and that the comprehensive literature proved the androgen hypothesis wrong. The same review pointed to experimental studies in animals suggesting that tribulus acts through the endothelium, the lining of blood vessels, and through nitric oxide, the molecule that relaxes penile arteries during an erection. Prescription PDE5 inhibitors such as sildenafil and tadalafil work on the same nitric oxide pathway, so the idea is biologically plausible. The nitric oxide mechanism has been shown in animals and cell work, not confirmed in human trials. The practical point for men is that a tribulus product sold for testosterone is being sold on the wrong mechanism. A man with low testosterone symptoms who takes tribulus is unlikely to see his blood test move, and a man whose erections improve should not assume his hormones changed.
How does tribulus compare with other testosterone boosters?
Tribulus sits with the majority of boosters that failed to raise total testosterone in controlled trials. A 2024 systematic review in the International Journal of Impotence Research by Morgado and colleagues screened two decades of research and included 52 studies covering 27 proposed testosterone boosters, with total testosterone versus placebo as the outcome. The review counted 10 studies of vitamin D, 5 of zinc or magnesium, 4 each of tribulus and creatine, and 3 each of Eurycoma longifolia (tongkat ali) and Withania somnifera (ashwagandha). The authors found that most boosters fail to raise total testosterone. Tribulus was not among the ingredients they rated effective or possibly effective in athletes, healthy men, men with late-onset hypogonadism or infertile men. Tribulus also appears in multi-ingredient blends, which complicates any claim on the label. Qureshi and colleagues found that the only human testosterone rises in their review came from combined supplements, so a blend that works, if it works, cannot be credited to its tribulus content.
How Much Placebo-Controlled Testosterone Data Each Booster Has
Number of studies per ingredient among 52 studies of 27 proposed testosterone boosters in a 2024 systematic review. Tribulus was not among the ingredients the reviewers rated effective or possibly effective (Morgado and colleagues, International Journal of Impotence Research, 2024).
Is tribulus safe to take?
In the controlled trials, tribulus caused no more adverse events than placebo over 1 to 3 months, but case reports describe serious harm. The 180-man Kamenov trial and the 2026 meta-analysis both reported adverse event rates similar to placebo. Those studies were short and not designed to catch rare reactions. A 2024 case in ACG Case Reports Journal from the University of Pittsburgh described a 46-year-old man who took tribulus daily for 2 months and developed severe jaundice. His bilirubin peaked at 48 mg/dL and his creatinine at 7.1, a sign of kidney failure. A liver biopsy matched drug-induced liver injury. He needed 3 sessions of plasmapheresis and recovered, with a later bilirubin of 1.1 mg/dL. A second 2024 case in the American Journal of Case Reports described a 71-year-old man on long-term atorvastatin who developed rhabdomyolysis, a breakdown of muscle tissue that can damage the kidneys, after adding tribulus. The authors cited recent research suggesting tribulus may inhibit CYP3A4, the liver enzyme that clears atorvastatin and many other common drugs. Single case reports cannot prove cause, but men on statins or other CYP3A4-cleared drugs have a specific reason to talk to their doctor before taking tribulus. The GamalEl Din trial also recorded small rises in AST and PSA, which matter for men having routine liver or prostate checks.
What should men take away from the tribulus research?
The research supports a narrow conclusion: tribulus does not reliably raise testosterone, and it may modestly improve erectile function through a non-hormonal route. The testosterone claim has been tested in healthy young men, athletes, older men with erectile dysfunction and infertile men, and the controlled trials keep finding nothing meaningful. The erection data are better but still thin. The pooled effect of 3.23 IIEF-5 points is real on paper, the largest trial was run with the product's manufacturer and the smaller independent trial found no difference from placebo. Doses in the trials ranged from 400 to 750 mg a day in most studies, while the Tribestan trial used 3×2 tablets of 250 mg a day, with products that vary widely in saponin content. A man who suspects low testosterone gets more from a morning blood test than from a supplement trial of his own. Testosterone is best checked early in the day and confirmed on a second sample. A man with erectile dysfunction should know it can be an early sign of heart and blood vessel disease, which is a reason to see a doctor regardless of what he decides about tribulus.
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