I do not know it must be in the persons chemistry or something. This product is amazing I am 29 years old and have been lifting for 12 years all natural. Never have I had a NO product like this one. My pumps are great workouts outstanding and it last for several hours. Great sets and more reps. I do not know if it is the way others take it, that they feel no pumps or simply chemistry but give it an honest run pre workout on a semi empty stomach you will like it. |