Unfortunately I have never had any luck with Nitraflex, but the product looks so amazing. I love PWO supps!! Love em!! I have tried so many and this is one of them that has not worked for me. I have a list that has worked well for me: Bettencourt D-stunner, Muscle Marinade (wow), Hemavol (powder stacked with something with caffeine) just to name a few that have worked well for me. I try to stay away from the pills, they don't work as well as the powder PWO. I always take a PWO before training (weights/BJJ)