Citrulline

Better at raising plasma arginine than arginine supplements. Moderate evidence for blood-pressure reduction and exercise performance.

A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.

Citrulline bypasses hepatic arginase, resulting in higher sustained plasma arginine than equivalent oral arginine doses. Meta-analyses show small blood-pressure reductions. Exercise studies show modest improvements in high-repetition resistance training and reduced perceived exertion.

• Raises plasma arginine more effectively than arginine itself
• May reduce blood pressure modestly
• Improves exercise tolerance in high-rep protocols

3–6 g/day of L-citrulline. Often taken 30–60 minutes before exercise.

• Mild GI discomfort at high doses

Low risk profile. Theoretical interactions with PDE5 inhibitors and nitrates due to NO pathway effects.

Performance benefits are modest and most evident in high-volume training protocols. Acute effects on maximal strength are inconsistent.

• Recovery40
• Muscle35
• Energy30