Mrs. D, Both Now Foods and Source Naturals offer the powdered form of L-Arginine and L-Citrulline through iHerb. I was getting good results as far as my feet not being so cold until I got an intestinal bug a couple of days ago and discontinued usage temporarily. I mix the L-Arginine in juice because it tastes so bad, but when I run out of those gigantic horse pills (L-Citrulline), I'm going to order the powder. My stomach hasn't reacted yet to the powder. Joan