L-citrulline
HorseFil amount: not published
- Found naturally in watermelon.
- Turned into arginine, then nitric oxide, which relaxes blood vessels.
- One small study used 1.5 g a day for a month; half the men reported a benefit.
- Cyclists taking 2.4 g a day for eight days rode faster in one study.
- Common amounts: 3–6 g a day.
Watch for: Bloating, cramping, diarrhea and sweating. Ask a doctor if you take blood-pressure or ED medicine. Source: Cleveland Clinic, “L-Citrulline Supplement Benefits and Side Effects”.



