If you’re lunging, it must be leg day, and if it’s leg day, you need all the help you can get. Enter GAT Nitraflex, a pre-workout test booster loaded with calcium fructopyranose borate, which, in a six-week study, was shown to increase total testosterone by more than 50% in healthy subjects.

It also features citrulline and arginine, both of which help to produce the powerful vasodilator nitric oxide. It can even help you focus pre-workout and when you’re in the gym, thanks to a slew of “cognitive enhancers.”

Get GAT Nitraflex at the Muscle & Fitness Store >>