Dry extract of Tribulus terrestris
Also known as: Puncture vine, Goat's head, Bindii, Dry extract of Tribulus terrestris, Tribulus terrestris
Overview
Tribulus terrestris is a plant whose dry extract is widely used as a dietary supplement, primarily marketed for its purported benefits in enhancing sexual function, increasing testosterone levels, and improving athletic performance. The extract is typically derived from the aerial parts or fruits of the plant. While traditionally used as an aphrodisiac, scientific evidence regarding its efficacy remains mixed and often inconclusive. Its main applications are in addressing erectile dysfunction and boosting libido. Research on Tribulus terrestris is moderately mature, with several clinical trials and systematic reviews, but the quality of evidence varies, and many studies have methodological limitations. The primary active constituents are thought to be steroidal saponins, such as protodioscin.
Benefits
Some evidence suggests that Tribulus terrestris supplementation may modestly improve erectile function and sexual satisfaction in men, particularly those with sexual dysfunction. A systematic review following PRISMA guidelines indicated inconsistent results across studies but noted potential improvements in this area. However, the effect sizes reported in controlled trials tend to be small or statistically nonsignificant. For testosterone levels, multiple systematic reviews, including one indexed in PubMed, consistently conclude that Tribulus terrestris does not significantly increase serum testosterone in healthy men or athletes. Similarly, robust evidence does not support claims of enhanced muscle strength or athletic performance. Any potential benefits, primarily related to sexual function, typically require several weeks of supplementation, generally 4–12 weeks, to manifest.
How it works
The exact mechanism of action for Tribulus terrestris is not fully understood in humans. Proposed mechanisms include the stimulation of androgen receptors or the modulation of luteinizing hormone, although these have not been conclusively demonstrated in human studies. The active constituents, particularly steroidal saponins like protodioscin, are thought to influence nitric oxide pathways, which could potentially lead to improved blood flow, a factor relevant to erectile function. However, no definitive molecular targets have been confirmed in human clinical studies, and the bioavailability of these active compounds can vary significantly depending on the extraction method and formulation of the supplement.
Side effects
Tribulus terrestris dry extract is generally considered safe when consumed at typical supplement doses. Mild gastrointestinal discomfort is the most commonly reported side effect, occurring in less than 5% of users. Uncommon side effects, affecting 1-5% of users, may include headache and insomnia. Rare adverse events are poorly documented but could potentially include allergic reactions. While no major drug interactions have been definitively identified, caution is advised when combining Tribulus terrestris with antihypertensive or diabetes medications due to theoretical concerns. It is contraindicated during pregnancy and breastfeeding due to a lack of sufficient safety data. Furthermore, special populations such as children or individuals with hormone-sensitive conditions should avoid its use.
Dosage
The minimum effective dose for Tribulus terrestris is not firmly established, but clinical trials commonly utilize dosages ranging from 250 mg to 1500 mg per day of a standardized dry extract. An optimal dosage range typically falls between 750 mg and 1500 mg daily, standardized to its protodioscin content, usually 40–60%. Doses exceeding 1500 mg per day have not demonstrated increased efficacy and may potentially heighten the risk of side effects. For optimal absorption, it is generally recommended to take Tribulus terrestris daily with meals. Standardized extracts are preferred to ensure consistent levels of active compounds. Due to the lipophilic nature of its saponins, absorption may be enhanced when co-administered with fats. No essential cofactors are required for its efficacy.
FAQs
Does Tribulus terrestris increase testosterone?
Current high-quality evidence, including systematic reviews, indicates that Tribulus terrestris does not significantly raise testosterone levels in healthy men or athletes.
Is it effective for erectile dysfunction?
Some men report improvements in erectile function and sexual satisfaction, but clinical evidence is mixed, and any observed effects tend to be modest and inconsistent across studies.
How long before effects appear?
Benefits, particularly those related to sexual function, generally become noticeable after 4 to 12 weeks of consistent supplementation.
Is it safe?
Tribulus terrestris is generally considered safe with mild side effects like gastrointestinal discomfort. However, it should be avoided during pregnancy or breastfeeding due to insufficient safety data.
Can it enhance athletic performance?
Evidence does not robustly support claims that Tribulus terrestris meaningfully improves muscle strength, endurance, or overall athletic performance.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11990417/ – This systematic review, following PRISMA guidelines, analyzed multiple randomized controlled trials on Tribulus terrestris. It found some evidence for modest improvements in sexual function and satisfaction in men, but noted inconsistencies across studies and no consistent increase in testosterone. The review highlighted heterogeneity in study designs and small sample sizes in some trials, yet its systematic approach lends it high quality.
- https://pubmed.ncbi.nlm.nih.gov/24559105/ – This systematic review examined randomized controlled trials involving healthy men and athletes. It concluded that Tribulus terrestris had no significant effect on serum testosterone levels or athletic performance. The review was limited by a relatively small number of high-quality RCTs, but its findings are consistent with other analyses, indicating moderate to high quality evidence.