Tribulus terrestris is an herb used in Traditional Chinese Medicine for the treatment of eye trouble, edema, stomach ailments, and sexual dysfunction. It is also used in Indian Ayurvedic medicine for the treatment of impotence and infertility, urogenital disorders, cardiovascular diseases, inflammation, and chronic pain.^[5]

Of the more than 70 compounds found in Tribulus terrestris, the most common include steroidal saponins and flavonoids, which are contained in the root and the fruit of the plant and appear to be largely responsible for its antioxidant, anti-inflammatory, antibacterial, and neurological properties.^[6] The particular composition of Tribulus terrestris largely depends on its geographical origin.^[7]

Tribulus terrestris is commonly claimed to have aphrodisiac properties. There is indeed some evidence that it can improve sexual desire, increase sexual satisfaction, and reduce symptoms of erectile dysfunction (ED) in men^{[8][9][4][10]} and enhance libido in women.^[11][12] These effects seem to be most prominent in people who are experiencing some form of sexual dysfunction. Current evidence fails to support that claim that Tribulus terrestris elevates testosterone levels.^[13][14]

Tribulus terrestris may also have benefits for reducing blood pressure and cholesterol^[15][16] and for reducing blood glucose in people with diabetes,^[17][18] though evidence is limited.

None of the clinical trials that have studied the effects of Tribulus terrestris have reported an increase in adverse side effects when compared to placebo treatments.^[7][19][4] While no toxicology studies have been conducted in humans, rodent studies that have administered Tribulus terrestris at a dose of 500 mg per kilogram of body weight (mg/kg) for 28 days (equivalent to a human dose of 80 mg/kg after adjusting for metabolic and size differences) didn’t observe any toxic side effects.^[20] In vitro studies have shown cytotoxic, genotoxic, and endocrine-disrupting effects of Tribulus terrestris, but it is unknown how this may translate to humans.^[21]

The mechanism by which Tribulus terrestris improves erectile function may involve an enhancement in the relaxation of penile smooth muscle tissue, increased intracavernous pressure, and elevated penile blood flow. These effects seem to be dependent on a greater release of nitric oxide (NO) from the endothelium of blood vessels.^[22][23][24]

Tribulus terrestris and its extracts may also have antioxidant and anti-inflammatory properties in vitro. Tribulus terrestris scavenges hydrogen peroxide and superoxide free radicals^[25] and increases the activity of the antioxidant enzyme superoxide dismutase.^[26] Furthermore, Tribulus terrestris might inhibit the production of inflammatory cytokines, including TNF-𝛼, interleukin 6, and interleukin 10.^[27]