The dosage of arginine / L-Citrulline that is needed appears to relate to the activity / exertion level. I started with 1 gram, worked up to 8.25 grams and when I felt okay, I cut it back to 3 grams. I was feeling fine at the 3 gram level.
Now that spring is here and I am back to landscaping / maintaining my large yard, I get tired out after a couple days of exertion. So now I am going back to 8.25 grams. That dosage level does help to offset the exertion. (A rainy day could help too. 🙂 )
So you have to "experiment" what dosage works for you at your current exertion level. Hope it helps. Remember to add at least a small amount of vitamin C, around 100mg.