Tribulus terrestris, a traditional Indian and Chinese herb sold as a supplement for sexual vitality and as a "natural testosterone booster," shows a modest, fragile sexual-function benefit in small studies. It does not meaningfully raise testosterone, except perhaps in men with low levels, and does not build strength or muscle. Side effects matched placebo in studies, but rare case reports describe serious liver and kidney injury. (Full Review)
| Marker | Target | Why |
|---|---|---|
| ALT and AST | ALT 7–56 U/L; AST 10–40 U/L | Safety check for liver injury |
| Total bilirubin | 0.1–1.2 mg/dL | Safety check: jaundice dominated reported cases |
| Creatinine and eGFR | Creatinine 0.7–1.3 mg/dL in men, 0.6–1.1 mg/dL in women; eGFR 90 mL/min/1.73 m² or higher | Safety check for kidney injury |
| Blood pressure | Below 130/80 mmHg | Expected to change: may fall |
| Fasting glucose and HbA1c | Fasting glucose 70–99 mg/dL; HbA1c 4.0–5.6% | May fall, mainly in diabetes |
| LDL cholesterol | Not specified in the ER | Expected to change: may fall |
| PSA (men) | 0–4.0 ng/mL | Safety check: a rise changes screening interpretation |
| IIEF-5 score (men) | 22–25 | Primary efficacy marker |
Cadence: Baseline before starting; liver and kidney tests at 4–8 weeks, then every three months during continued use; blood pressure weekly at home for the first month; glucose, LDL and PSA (men) at three months; questionnaire at 4 and 12 weeks. No improvement by 12 weeks defines non-response.