L arginine

L-arginine supports nitric oxide production and vasodilation, but L-citrulline is often preferred because it converts to arginine and remains in the bloodstream longer. 1

• L-citrulline conversion: It converts to L-arginine, increasing nitric oxide availability and promoting blood-vessel dilation and blood flow. 2
• Performance and growth hormone: Arginine-pathway supplements are used to support blood flow and gym performance; L-citrulline may also increase growth hormone. 3 4
• Cautions: These supplements can lower blood pressure, and L-arginine or L-citrulline may worsen cold-sore outbreaks in susceptible people. Supplement contents can also differ from what the label claims. 5 6 7