Taking arginine supplements for just three days won’t make you stronger or more powerful during short, intense workouts like sprinting or lifting heavy weights—even if you’re already a well-trained athlete.

Taking a specific amount of arginine supplement for just three days doesn’t change the levels of nitric oxide in the blood of highly trained male athletes when they do short, intense workouts.

Taking L-arginine supplements while doing intense interval training won’t make highly trained female handball players any faster or stronger in short sprints than training alone.

Taking 6 grams of L-arginine might help young men use less oxygen when they exercise at a steady pace, which could mean their body works more efficiently.

Taking L-arginine supplements every day for 8 weeks won’t make highly trained female handball players any better at running for 12 minutes straight.

Taking a daily L-arginine supplement for two weeks doesn't help lower ammonia levels in the blood when healthy young men cycle hard, because the supplement group and the placebo group ended up with pretty much the same ammonia levels.