Tribulus terrestris does not reliably raise testosterone in men: systematic reviews of human trials have found little to no effect on hormone levels. The tribulus terrestris evidence is more interesting for erectile function, where a few trials report modest benefits in men with mild-to-moderate erectile dysfunction, but those studies are small, often industry-funded and of mixed quality.
That gap between marketing and research is why tribulus is worth understanding before you buy a “testosterone booster” that leans on it. Here is what the studies actually show.
Key takeaways
- Human trials mostly show no rise in testosterone
- Some small trials suggest modest help for mild ED
- Study quality is low and often industry-funded
- Usually well tolerated, but check medications first
What is tribulus terrestris?
Tribulus terrestris is a flowering plant, sometimes called puncture vine, used for centuries in traditional Ayurvedic and Chinese medicine. Its fruit and leaves contain compounds called steroidal saponins, especially protodioscin, which supplement makers say drive its effects. Commercial extracts are usually standardized to between 40% and 60% saponins, and the plant’s chemistry varies by region, so two tribulus products may not be comparable.
Tribulus became famous in bodybuilding after reports that Eastern European athletes used it. Animal studies did show testosterone increases, and that is where the “natural testosterone booster” reputation started.
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Tribulus terrestris evidence for testosterone
The human data tell a different story than the animal studies.
A 2014 systematic review in the Journal of Dietary Supplements by researchers at Kingston University looked at 11 studies. It found that tribulus taken on its own did not raise testosterone in humans; increases appeared only in studies where tribulus was mixed with other ingredients, which makes it impossible to credit tribulus. The authors concluded it was ineffective for raising testosterone in people, even though some animal studies showed an effect.
A newer 2025 systematic review in Nutrients by Vilar Neto and colleagues reached a similar conclusion. Of 10 studies with 483 men in total, eight found no significant change in testosterone. The two that did report increases enrolled men who started with low testosterone, and both were rated as poor methodological quality. The authors found no robust evidence that tribulus raises testosterone.
Studies in athletes are also unconvincing. In trials of men doing strength training, including elite rugby players, tribulus did not improve strength or body composition more than a placebo.
Does tribulus help erectile function?
This is where the research is more promising, though still limited.
The largest trial, published in Maturitas in 2017 by Kamenov and colleagues, randomized 180 men aged 18 to 65 with mild-to-moderate erectile dysfunction to a standardized Bulgarian tribulus extract or a placebo for 12 weeks. Erectile function scores improved more with tribulus than with placebo, and side effects were similar in both groups. Testosterone levels did not change, which suggests any benefit works through other pathways, such as blood vessel relaxation.
There are important caveats. The extract’s manufacturer funded the study, two authors had ties to the company, and only 86 men per group completed it. The results apply to that specific extract, not to every tribulus product.
The 2025 Nutrients review found that three of five studies measuring erectile function reported benefits, usually at doses of 400 to 750 mg a day for one to three months. The authors called the evidence low quality and said tribulus is not a substitute for first-line ED treatment.
Important: Erection problems can be an early warning sign of heart disease, diabetes or high blood pressure. If they last more than a few weeks, see a doctor before trying any supplement. Our guide to why you might not be getting hard anymore covers common causes.
Libido: a possible but uncertain effect
Some small studies report that tribulus improves sexual desire in men and women with low libido, typically at 750 to 1,500 mg a day. These trials are short and small, and libido is especially prone to placebo effects, so treat this as a possibility rather than an established benefit. For other options, see our look at the best libido boosters for men.
Typical doses
Studies have used a wide range of doses:
- Erectile function: roughly 400 to 1,500 mg a day of a standardized extract, for one to three months.
- Libido: 250 to 1,500 mg a day.
- Saponin content: usually 40% to 60%. A higher-saponin extract generally means a smaller dose.
Because extracts vary so much, follow the product label and don’t combine several tribulus-containing supplements.
Side effects and safety
In clinical trials, tribulus is usually well tolerated, with side effects similar to placebo. The most commonly reported problems are mild stomach upset and reflux. A few points deserve caution:
- Kidneys: a rat study raised concerns about kidney effects, and there is a published case of toxicity in a man who used tribulus to prevent kidney stones. Avoid it if you have kidney disease.
- Blood sugar: one trial in women with type 2 diabetes found tribulus lowered blood sugar, so check with a doctor if you take diabetes medication.
- Hormone-sensitive conditions: men with prostate cancer or other hormone-sensitive conditions should avoid it unless a doctor approves.
- Athletes: tribulus is not a banned substance, but contaminated supplements can be. Choose third-party tested products.
- Long-term safety: most studies last three months or less, so long-term safety isn’t well studied.
Is tribulus worth taking?
If your goal is higher testosterone, the evidence says no. Tribulus has had more than a decade of human research, and the best reviews keep finding no reliable effect on hormone levels.
If your goal is mild erectile or libido support, tribulus is a low-cost, generally well-tolerated option with some early evidence, but you should talk to a doctor first, especially to rule out underlying causes.
If you’re shopping for a testosterone supplement, it helps to know which formulas skip tribulus entirely. Our TestRX review breaks down one such formula, built around D-aspartic acid, fenugreek and ZMA, and our testosterone support comparison ranks the main options by the strength of their evidence. For a related herb with better trial data, see our guide to Korean red ginseng for erectile function.
Does tribulus terrestris increase testosterone?
Not reliably. Systematic reviews from 2014 and 2025 found that most human trials showed no significant change in testosterone. The few positive studies involved men with low starting levels and were of poor quality.
Is tribulus good for erectile dysfunction?
Some small trials, including a 2017 industry-funded study of 180 men, found modest improvements in men with mild-to-moderate ED. The evidence is low quality, and tribulus is not a replacement for medical evaluation or proven ED treatments.
What are the side effects of tribulus?
Most people tolerate it well; mild stomach upset and reflux are the most common complaints. People with kidney disease, diabetes or hormone-sensitive conditions should check with a doctor first.
How long does it take for tribulus to work?
Trials of erectile function and libido generally ran for one to three months, and one large trial saw differences by four weeks. If nothing changes after about three months, it is unlikely to help.