Tribulus

Tribulus terrestris

ZygophyllaceaeSouthern Europe, southern Asia, Africa, Australia, and the Americas; cosmopolitan weed of warm climates

Description

overall appearance

Prostrate to spreading annual or perennial herb forming dense mats 10–60 cm in diameter and 10–30 cm tall; covered in silky hairs. Valued across traditional systems for its fruits, leaves, and roots despite its weedy habit.

roots

Taproot system with deep main root and spreading lateral roots; can penetrate 50–90 cm in dry soils to access deep moisture; off-white, woody at crown

stem

Prostrate, spreading, much-branched stems 10–60 cm long; covered with spreading white hairs; pinnate leaves give a feathery appearance to each branch

leaves

Pinnately compound, 2.5–5 cm long, with 3–8 pairs of leaflets; leaflets oblong-ovate, 5–15 mm long and 3–7 mm wide; silky-hairy beneath; stipules present

flowers

Bright yellow, 5-petaled flowers 6–10 mm in diameter; solitary in leaf axils; 10 stamens; open in morning, close by afternoon

fruits/seeds

Distinctive star-shaped woody capsule (the caltrop) 8–12 mm wide, splitting into 5 segments each bearing 2–4 sharp rigid spines 4–6 mm long; 1–5 seeds per segment

Active Compounds

Steroidal saponins: protodioscin (primary bioactive), protogracillin, dioscin, tribulosinFurostanol glycosides: terrestrosins A–ESpirostanol saponins: tigogenin and neotigogenin glycosidesFlavonoids: kaempferol, quercetin, isorhamnetin, rutinAlkaloids: harman (β-carboline), norharmaneCinnamic acid amides: N-trans-feruloyltyramineTerrestribisamide and other amidesPhytosterols: β-sitosterol, stigmasterol

Traditional Uses

Ayurveda: Gokshura — used as diuretic, tonic for urinary tract health, and aphrodisiac; part of Dashamoola formula
TCM: Ji Li — liver tonic; used for headache, dizziness, eye redness, and skin conditions from 'liver yang rising'
Bulgarian folk medicine: used as male sexual tonic and athlete performance enhancer since 1970s–80s
Unani medicine: general tonic for kidney and urinary complaints, including dysuria and calculi
Greek and Roman traditional use for kidney stones and liver conditions
South African traditional medicine: diuretic and tonic for general weakness
Indian Ayurvedic use in managing gout and hyperuricemia via xanthine oxidase inhibition
Traditional treatment for edema and ascites in multiple Asian medical traditions

Modern Applications

Male sexual function: meta-analysis (Santos et al., 2014) found significant improvement in erectile function scores; protodioscin may stimulate androgen receptor activity
Testosterone modulation: human RCTs show inconsistent results; animal studies suggest LH-mediated testosterone increase
Urinary tract health: antispasmodic and diuretic effects; clinical evidence for reducing urinary symptoms in BPH
Antihypertensive: saponins shown to reduce blood pressure in animal models via ACE inhibition and calcium channel blocking
Cardiovascular: protodioscin shown to reduce ischemia-reperfusion injury; protective against cardiotoxicity in animal models
Antidiabetic: steroidal saponins reduce blood glucose and improve insulin sensitivity in streptozotocin-diabetic animals
Antimicrobial: extracts active against MRSA, Candida albicans, and other pathogens
Kidney stone prevention: aqueous extract shown to inhibit calcium oxalate crystallization in vitro and in animal models

⚠️ Safety Information

Contraindications

Pregnancy: uterotonic and hormonal effects; contraindicated
Hormone-sensitive cancers (prostate, breast): androgenic and estrogenic activity may stimulate growth
Prostate hyperplasia (BPH) without medical guidance: potential androgenic stimulation requires monitoring
Steroid-sensitive conditions: steroidal saponins may affect hormone balance

Side Effects

Gastrointestinal upset (nausea, cramping, diarrhea) at doses above 1,500 mg/day
Gynecomastia reported in men taking high-dose supplements long-term
Photosensitivity (Geeldikkop): secondary photosensitization in sheep consuming large quantities; rare in humans
Insomnia or agitation due to mild stimulant activity of alkaloid fraction

Drug Interactions

Antidiabetic drugs (metformin, insulin): additive hypoglycemic effect; monitor blood glucose closely
Antihypertensives: additive blood pressure lowering; monitor cardiovascular parameters
Testosterone/androgen therapies and anabolic steroids: potential additive androgenic effect; avoid concurrent use
Anticoagulants (warfarin): may alter platelet aggregation; monitor INR