Tribulus and the Testosterone Question

Tribulus is a botanical whose name is very often followed, in a search box, by a hormone. Type it into a search engine and the suggested completions include tribulus testosterone, does tribulus terrestris boost testosterone and how much tribulus per day for testosterone.

This site has a specific reason to take the question seriously. The larger Protoflow packs ship with four digital bonuses, and one is titled 10 Ways to Turbocharge Your Testosterone. Our post on when the bonus makes the claim looked at that as a matter of regulation: the bottle names no hormone, and the ebook cover names one. It did not ask the follow-up question, which is the one this post asks. If somebody did believe the title, and did think the tribulus in the capsule was the reason, what does the published evidence say about tribulus and testosterone in men?

The answer comes in three parts: trials that measured the hormone directly, reviews that pooled them, and the separate, more mixed evidence for sexual function, which is where tribulus has a slightly better story and where its dosing looks very different from the label’s.

The direct test is simple to describe. Give some men tribulus and some men a placebo, and measure their testosterone. Several groups have done it, in different kinds of men, and the results are consistent.

Neychev and Mitev, in Bulgaria, gave 21 healthy young men either tribulus extract at 10 or 20 mg per kilogram of body weight, or placebo, for four weeks, and took blood at six time points across it (PMID 15994038). Testosterone, androstenedione and luteinising hormone did not differ between the groups, and every result stayed within the normal range. The authors concluded that tribulus saponins possess neither direct nor indirect androgen-increasing properties. The dose is worth noticing: for a man weighing 80 kg, 10 to 20 mg per kilogram is 800 to 1,600 mg a day. That is an illustration, not a subject, since the men in the trial weighed between 60 and 125 kg.

The athletes’ trials found the same thing from the performance end. Resistance-trained men taking about 3.2 mg per kilogram for eight weeks showed no improvement in body composition or exercise performance beyond what placebo produced (PMID 10861339). Elite rugby league players taking 450 mg a day through five weeks of pre-season training gained strength and lean mass, with no difference from their placebo-taking teammates (PMID 17530942). The same paper checked the ratio anti-doping laboratories use to detect testosterone abuse and found it unchanged, which is also an indirect answer to whether the herb raised the hormone.

And in the one trial in this group that recruited men with erectile dysfunction, 30 men aged 40 and over took 800 mg a day for a month (PMID 24630840). Their total testosterone was 417 ng/dL before and 409 after on tribulus, against 443 before and 466 after on placebo. The authors concluded that at the dose and interval studied, tribulus was not more effective than placebo for either erectile symptoms or serum total testosterone.

None of these trials is large, and this post is not going to pretend otherwise. Together they are what the reviews had to work with, and the reviews are less equivocal than you might expect.

Tribulus does have a second reputation, for sexual function, and here the trials genuinely disagree, which makes it the most interesting part of the literature.

The 2025 review found that tribulus improved erectile dysfunction in three of the five studies that assessed it. The largest positive trial, published in Maturitas in 2017, randomised 180 men aged 18 to 65 with mild or moderate erectile dysfunction to tribulus or placebo for 12 weeks (PMID 28364864). The men took a branded product, and each film-coated tablet contained 250 mg of a dried herb extract at a stated ratio of 35–45 to 1, standardised to at least 112.5 mg of furostanol saponins. The dose was three times two tablets a day, so six tablets, which is 1,500 mg of extract daily. The erectile function score improved more on tribulus than on placebo, by 2.70 points (95% CI 1.40 to 4.01) on an intention-to-treat basis, with improvements in intercourse satisfaction, orgasmic function, desire and overall satisfaction, and no difference in adverse events.

Against that stands the trial of 30 men in the table above, where 800 mg a day for 30 days produced no difference from placebo. Both results can be true, because the two trials are so different: 180 men against 30, 12 weeks against 30 days, a standardised branded extract against a dose of unspecified material in the abstract. That is the practical lesson of this whole area. Studies of a herb are studies of a specific product at a specific amount, and a result belongs to that product.

It is also worth noticing what the positive trial did not claim. It measured erectile function in men with erectile dysfunction. The abstract does not report testosterone as an outcome, and the 2014 review proposes a nitric-oxide mechanism that would not run through the hormone.

The safety picture is mostly quiet, with one thing you should hear about rather than have discovered later.

The reassuring part first. In the 180-man Maturitas trial, there was no difference in the incidence of adverse events between tribulus and placebo, and no drug-related serious adverse events. This site’s ingredients page records no NCCIH page and no NIH fact sheet for tribulus, so there is no federal summary to quote in either direction, which is the position seven of the eleven botanicals on this panel are in.

Now the part to hear. A 2024 case report in ACG Case Reports Journal describes a 46-year-old man who took tribulus supplements daily for two months and developed severe jaundice and admission to hospital, with a peak bilirubin of 48 mg/dL, kidney dysfunction, and a liver biopsy consistent with drug-induced liver injury (PMID 38328764). He was treated with three sessions of plasmapheresis, recovered kidney function, and had a bilirubin of 1.1 mg/dL at follow-up. The authors note that tribulus has been linked to severe jaundice and death in grazing animals, and that only a few case reports of liver toxicity in humans exist.

How much weight should a single report carry? Not a great deal, and not none. One case cannot tell you how often such an event occurs, and the abstract does not say what product or dose was involved, so it is impossible to say what it implies for a 120 mg row. But it is a documented serious event, and a person with liver or kidney disease, or one taking other medicines, has a reason to raise it. That is also the reason the label’s caution line, to consult a physician before use if you take any medication, is worth following rather than skipping.