All amino acids are pivotal for making gains in muscular size and strength; however there are three extremely vital essential amino acids that expedite muscle protein synthesis.
The name branched-chain amino acids is derived from the molecular structure of valine, isoleucine, and leucine. They feature branched chains of carbon extending from their primary carbon structure. A recent study presented at the 2009 Annual Meeting of International Society of Sports Nutrition found that trained lifters taking a BCAA supplement around workouts for eight weeks gained about twice as much muscle and strength as those taking a whey protein shake without additional BCAAs.
The unique property of BCAAs is they are shuttled directly to the muscles rather than through the liver first. The muscle can use the BCAAs directly for fuel or to build and repair itself. This means that during workouts they function as a fuel source and when the workout is complete they stimulate muscle growth and recovery. BCAAs sustain energy during a workout and maintain intensity from start to finish.
Research has shown that BCAAs, especially leucine, increases muscle growth by directly stimulating muscle protein synthesis. Leucine acts like a key that turns on the process that strings amino acids together to build muscle. Leucine also boosts insulin levels. Insulin is an anabolic hormone that further stimulates protein synthesis. BCAAs also boost natural growth hormones; the higher the growth hormone levels after workouts, the greater the increase in muscle size and strength. BCAAs also influence cortisol. Athletes taking BCAAs have lower levels of cortisol during exercise. This blunting of cortisol levels increases muscle growth because cortisol encourages muscle breakdown and interferes with the anabolic hormone testosterone
BCAAs also work via the brain to delay fatigue. During exercise, the neurotransmitter serotonin signals to the brain that the body is fatigued. The amino acid tryptophan is responsible for producing serotonin in the brain, while the BCAAs, notably valine, compete with tryptophan for entry into the brain. Taking BCAAs before workouts lowers the amount of tryptophan that gets into the brain and therefore delays fatigue.
For consumption, a single solid dose of BCAAs is around 5-10 grams. The most critical time to take them is around workouts, so mix them in your pre- and post-workout shakes. You can also consider taking a dose of BCAAs right after waking up to stop the muscle breakdown that takes place during sleep. An additional dose can be taken throughout the day to get an energy boost, reduce hunger, and aid muscle growth.