not sure exactly but I think L-Leucine is the main EAA for anti catabolism. As far as both go, either seems good. PW doesnt seem to disclose their formula as it is a blend. They have BA and CM but it's underdosed so it really wont do that much for you. in terms of BA and CM. X-tend also underdosed. but they disclose the amount of L-Leucine. Id say pick one of these, buy some nutraplanet bulk BCAA and then mega dose it. Id recommend PW because ive tried it, flavors alright, not great though. Maybe xtend flavor is better.