Sure, you know that the branched-chain amino acids — leucine, isoleucine and valine — are critical for muscle growth. But don’t forget how critical these bad boys are for energy. The muscles use BCAAs for fuel during workouts, and research shows they work on the brain to blunt fatigue. This all leads to more intense workouts in which you can be stronger for longer. And that builds muscle in the long run, as research confirms in those taking BCAAs around workouts.

Citrulline Malate

Citrulline is not only a powerful nitric oxide booster but it also delays fatigue and drives up energy levels, especially in this form by binding malic acid (malate) to citrulline. Malic acid helps the body convert the lactic acid produced during workouts into energy. Citrulline aids the removal of ammonia from the body. Ammonia is a toxic compound produced during workouts that induces fatigue. By removing more ammonia, citrulline boosts energy and delays fatigue. In fact, clinical studies confirm that subjects taking citrulline malate experience less fatigue and have higher energy levels.

TAKE IT LIKE THIS: Within 30 minutes before every workout take 5–10 grams of BCAAs and 2–6 grams of citrulline malate with your preworkout protein shake.

— Jim Stoppani, PhD