Tribulus
A Mediterranean and Asian herbal long marketed as a natural testosterone booster. Multiple RCTs and systematic reviews find no effect on serum testosterone in healthy young men, athletes, or older men. Modest, inconsistent benefits exist for erectile function and female sexual desire. Rare case reports of severe liver injury — including one death.
Quick decision guide
May help most
Men or women with low libido or mild sexual dysfunction who want to try a plant option after discussing with a clinician — keep expectations modest and watch for liver symptoms.
Common dosing range
750–1,500 mg/day of standardised extract (typically 40–60% saponins) in divided doses.
When to expect effects
Sexual-function trials measured 4–12 week endpoints. Don't expect overnight changes.
Watch out for
No testosterone boost — that claim is the central marketing pitch and the evidence is clearly negative. Rare but serious hepatotoxicity.
Evidence snapshot
What is it
Tribulus is the genus name for a group of flowering plants in the caltrop family, with Tribulus terrestris being the most widely used species in supplements. The name 'tribulus' on supplement labels typically refers to T. terrestris (puncture vine) used for sexual function and athletic performance.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
Erectile dysfunction (mild-to-moderate) Limited Evidence | +3 to +7 point improvement in IIEF-EF score vs placebo at 12 weeks; testosterone unchanged | Men with mild-to-moderate ED who want to try a non-prescription option before PDE5 inhibitors | 12 weeks in the trial endpoints |
Female sexual desire and arousal Limited Evidence | +3-point greater improvement in total FSFI score vs placebo over 4 weeks (small trial) | Women with diagnosed HSDD or low desire wanting a non-hormonal trial option | 4–12 weeks in published trials |
Testosterone elevation in men Mixed Evidence | No measurable increase in total or free testosterone across multiple RCTs in healthy, athletic, or hypogonadal men | None — the claim is unsupported | Trials ran up to 12 weeks with no signal |
Athletic performance and body composition Mixed Evidence | No significant effect on strength, body composition, or performance across systematic-review trials | None — no evidence of performance benefit | Trials ran 4–12 weeks without significant effect |
Erectile dysfunction (mild-to-moderate)
- Effect
- +3 to +7 point improvement in IIEF-EF score vs placebo at 12 weeks; testosterone unchanged
- Best fit
- Men with mild-to-moderate ED who want to try a non-prescription option before PDE5 inhibitors
- Time
- 12 weeks in the trial endpoints
Female sexual desire and arousal
- Effect
- +3-point greater improvement in total FSFI score vs placebo over 4 weeks (small trial)
- Best fit
- Women with diagnosed HSDD or low desire wanting a non-hormonal trial option
- Time
- 4–12 weeks in published trials
Testosterone elevation in men
- Effect
- No measurable increase in total or free testosterone across multiple RCTs in healthy, athletic, or hypogonadal men
- Best fit
- None — the claim is unsupported
- Time
- Trials ran up to 12 weeks with no signal
Athletic performance and body composition
- Effect
- No significant effect on strength, body composition, or performance across systematic-review trials
- Best fit
- None — no evidence of performance benefit
- Time
- Trials ran 4–12 weeks without significant effect
Evidence for 4 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
Erectile dysfunction (mild-to-moderate)
Supplement benefitTwo reasonably-sized RCTs in men with mild-to-moderate ED (Roaiah 2016, n=30; Kamenov 2017, n=180) found that standardised tribulus extract at 750 mg/day for 12 weeks improved IIEF erectile-function scores more than placebo (average +3–7 points). Testosterone did not change in either trial — the mechanism is likely independent of androgens (possibly NO-pathway mediated). Effect sizes are smaller than PDE5 inhibitors and the longer-term durability is unknown.
Bottom line: Modest benefit possible — about half the effect size of PDE5 inhibitors. Reasonable to try for 12 weeks; escalate if no benefit.
Female sexual desire and arousal
Supplement benefitAkhtari 2014 randomised 67 women with hypoactive sexual desire disorder (HSDD) to Tribulus 7.5 mg/kg/day or placebo for 4 weeks. The tribulus group showed greater improvement in FSFI desire and arousal subscales (+5.5 vs +2.4 total FSFI change). The trial is small and short, but the signal is consistent across a few other small trials in pre- and post-menopausal women. Mechanism unclear; testosterone unchanged.
Bottom line: Worth a short trial for HSDD; effect size is modest and the evidence base is small.
Testosterone elevation in men
Supplement benefitTribulus's central marketing claim — that it raises testosterone — is not supported by quality RCTs. Neychev 2005 (healthy young men, 20 mg/kg/day, 4 weeks) found no T change; Saudan 2008 (athletes) found no T/E ratio change; multiple subsequent trials in older men with mild hypogonadism have been similarly null. Two systematic reviews (Pokrywka 2014, Santos 2014 meta-analysis) confirm this.
Bottom line: Don't take tribulus for testosterone. If you have low T symptoms, see a doctor for proper workup and treatment.
Evidence is mixed
Bodybuilding and supplement-industry sources cite preliminary in-vitro and primate data, but no human RCT shows a testosterone effect. The negative human evidence is consistent and well-established.
Athletic performance and body composition
Supplement benefitA 2014 systematic review of 12 trials of Tribulus terrestris for athletic performance found the majority showed no significant effect on muscle strength, body composition, exercise performance, or testosterone. The few positive trials had methodological problems (small samples, no blinding, no testosterone confirmation). Tribulus does not appear on WADA's prohibited list because it has no detectable anabolic effect.
Bottom line: Skip it for the gym. Spend the money on protein, sleep, and program design.
How it works
How to take it
What to track
Bottom line: Take 750 mg of a 40–60% saponin standardised extract once or twice daily for a 12-week trial. Stop if no benefit, and stop immediately for any liver symptoms.
3 commercial forms
Compare the main delivery options and what they’re best suited for.
Standardised aerial-parts extract (40–60% saponins)
Trial formThe form used in most clinical trials, including the Roaiah and Kamenov ED studies and the Akhtari female sexual-function study. Extract is concentrated 4:1 to 10:1 and standardised to saponin content. Best choice if matching trial protocols matters to you.
Standardised saponin content; the form with the most human trial data.
Crude tribulus powder
Cheap, variableDried and ground whole-plant powder, typically at 1,000–2,000 mg per serving. Saponin content varies widely by region, harvest time, and plant part. Hard to compare to trial doses; potency unpredictable.
Highly variable saponin content; trial-data extrapolation unreliable.
Tribulus + 'T-booster' stack
AvoidMulti-ingredient products combining tribulus with fenugreek, ashwagandha, D-aspartic acid, zinc, vitamin D, etc. The combined evidence base is thin, and stacking herbal hepatotoxicity risk isn't a great idea given tribulus's case reports. Avoid in favour of single-ingredient extracts.
Combination products have less standardised evidence; harder to attribute effect or side effect to any one ingredient.
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Serious risks
Acute liver injury (rare but serious): NIH LiverTox documents case reports of hepatotoxicity from tribulus-containing supplements, including one well-documented fatal case in a young man. Mechanism unclear; may be idiosyncratic or related to contaminants.
Sheep grazing on Tribulus terrestris ('geeldikkop') develop a photosensitive liver and kidney syndrome. Whether the same toxins reach significant levels in commercial human supplements is uncertain.
Prostate symptoms: occasional case reports of prostate enlargement, urinary hesitation, or new lower-urinary-tract symptoms with chronic tribulus use; causality not established.
Who should avoid it
- Anyone with liver disease, abnormal liver enzymes, or taking hepatotoxic medications — rare but real hepatotoxicity risk.
- Pregnant or breastfeeding people — animal studies show hormonal effects on the developing fetus; no human safety data.
- People with hormone-sensitive cancer (prostate, breast, ovarian) — in-vitro hormone-modulating effects make the safety profile uncertain.
- Patients on diabetes medication (insulin, sulfonylureas) — tribulus may have hypoglycemic activity; monitor blood sugar.
- Patients on antihypertensive medication — animal data suggest BP-lowering effect; possible additive hypotension.
Pregnancy & breastfeeding
Avoid in pregnancy and breastfeeding. Animal studies show fetal hormonal effects; no human safety data. The libido and sexual-function applications are not pregnancy-appropriate use cases.
Bottom line: Generally tolerated at typical doses, but the rare hepatotoxicity signal is real and serious. Don't combine with other potential liver-stressors; stop immediately for liver symptoms.
Interactions
Tribulus may have diuretic effects (animal data) that could increase lithium levels by reducing renal clearance. Monitor lithium levels if combining.
Tribulus may lower blood glucose; additive hypoglycemia possible. Monitor blood sugar closely if combining.
Animal data show BP-lowering effects; possible additive hypotension with ACE inhibitors, ARBs, beta-blockers, or diuretics.
Additive liver injury risk given tribulus's rare hepatotoxicity signal. Avoid combination or monitor liver enzymes.
Limited reports suggest possible INR alteration. Monitor INR if starting or stopping tribulus.
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
Frequently asked questions
Is tribulus the same as tribulus terrestris?⌄
On supplement labels, 'tribulus' typically refers to Tribulus terrestris (puncture vine). The genus contains other species, but T. terrestris is the most widely used.
Does tribulus increase testosterone?⌄
Most controlled trials in healthy men have not shown significant testosterone increases with tribulus, despite marketing claims.
Can tribulus improve athletic performance?⌄
Controlled trials in athletes generally do not show consistent benefits on strength or muscle mass.
How long until I notice effects?⌄
Effects, when present, typically emerge over 4 to 12 weeks of consistent use, not acutely.
Is tribulus safe to take?⌄
Generally well tolerated at typical doses. Avoid in pregnancy, breastfeeding, hormone-sensitive conditions, and discuss with a clinician if you take prescription medications.
References by claim
Testosterone elevation in men
Erectile dysfunction (mild-to-moderate)
Female sexual desire and arousal
Akhtari et al., 2014 — DARU Journal of Pharmaceutical Sciences (2014) link
Athletic performance and body composition
Qureshi et al., 2014 — Journal of Dietary Supplements (2014) link
Safety
LiverTox: Clinical and Research Information — NIH — National Institute of Diabetes and Digestive and Kidney Diseases (2020) link
Track Tribulus with Pilora
Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.
Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.