Yes, even people who compete can take this formula. There are no banned substances, this is an all natural Amino-based blend which provides natural support for strength training / powerlifting
Yes, Nitric Oxide is a favorite for bodybuilders to take before lifts
Nitric Oxide is most beneficial prior to exercise, recommended to be taken pre-workout. This isn't your traditional pre-workout formula with all the stimulants, this is a pump-only formula for better vasodilation & lean muscle mass.
Weight gain results primarily from changes in diet. Nitric Oxide adds lean muscle mass by allowing for harder reps / muscle breakdown while weight training. Diet is necessary as a recovery agent along with sufficient protein / carb / fat intake.