Bodybuilder's Guide to BCAAs

Muscle growth, strength, energy and even fat loss

Bodybuilder's Guide to BCAAs

Before creatine, arginine and whey protein ranked supreme as popular bodybuilding supplements, the branched-chain amino acids were the hot ticket for bodybuilders. Today, BCAAs are back on the must-have list of supplements because bodybuilders have found that they work well to enhance muscle growth, strength, energy and even fat loss. If you’re not using them, here’s your guide to why you should.


The BCAAs comprise three essential amino acids — leucine, isoleucine and valine. The name “branched-chain amino acids” is derived from the structure of these aminos — each has a forked outcropping that looks a bit like a branch. How essential are these three aminos? Well, although there are about 20 amino acids that the muscles use for muscle growth, the three BCAAs make up one-third of the total amino acids in the body’s muscles.

What’s really special about these three aminos is how the body handles them. When you ingest amino acids (as individual aminos or as protein), they first travel to the liver, which immediately breaks them down and uses them for fuel if the body needs them for energy rather than for rebuilding muscle and other tissues. Yet, the liver tends to spare BCAAs, sending them directly to the muscles to be used for building muscle or for fuel.

The muscles can use BCAAs, unlike other aminos, directly for fuel. This gives BCAAs two unique properties. First, during workouts, muscles readily use BCAAs for fuel. Second, during rest, such as after workouts, BCAAs are used for building muscle. These are two important considerations when it comes to the timing of supplementation: they make pre- and postworkout the critical time periods for taking BCAAs.


BCAAs are

readily used for fuel by the muscles during workouts; thus, intense and longer workouts will rob more BCAAs from your muscles. To counteract this, take a BCAA supplement right before you train — because supplemental BCAAs are readily available to the muscle as a direct source of energy, your energy levels will be higher during the workout than if you had not done so.

Besides boosting energy levels by providing a direct fuel source, BCAAs also enhance energy through another mechanism — one that involves the brain. French researchers discovered that during exercise, an amino acid metabolite known as 5-hydroxytryptamine (5-HT) signals the brain that the body is fatigued, causing it to reduce muscle strength and endurance. The amino acid tryptophan is responsible for producing 5-HT in the brain, which the BCAAs, namely valine, compete with for entry. Several research studies have confirmed that taking BCAAs before workouts lowers the amount of tryptophan that gets into the brain, thus lessening 5-HT levels and fatigue. Therefore, BCAA ingestion can help to prevent feeling fatigued during workouts, which will allow you to train harder and longer, encouraging greater muscle growth. BCAA supplementation can also help to enhance mood and brain function by reducing brain fatigue through this same mechanism.

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