L-Arginine
What it is
An amino acid that your body converts into nitric oxide, which relaxes blood vessels. Multiple trials show it modestly lowers blood pressure and improves erectile function. However, L-citrulline actually raises blood arginine levels more effectively than arginine supplements themselves. May cause digestive upset at doses above 6 g. Avoid after a heart attack as the VINTAGE-MI trial showed increased mortality.
Dose
3–6 g/day in divided doses; L-citrulline may be more effective; AVOID after recent heart attack
Time of day & tips
Take on an empty stomach 30–60 min before exercise or activity. Split into 2–3 doses to reduce stomach upset. Do not use after a heart attack.
Compare or learn more
Compare with another supplement →
Browse by symptom →
Open the full interactive view →