The branched-chain amino acids, or BCAAs, so called because of their forked (or “branched”) chemical structure, are three specific amino acids: leucine, isoleucine, and valine. These powerhouse aminos are unique among all amino acids. They perform several critical metabolic and physiological functions, and can provide multiple physique and performance benefits for people who want to build muscle, burn fat, and support overall recovery from their workouts. Let’s take a closer look at what BCAAs are, how they work, how to utilize them in your supplement arsenal, and how to get maximum benefit from taking them.
WHAT ARE AMINO ACIDS AND WHAT DO THEY DO?
BCAAs are three of the nine essential amino acids—essential meaning that we must provide them to our bodies through nutrition or supplementation. Unlike all other amino acids, BCAAs are primarily metabolized and utilized in skeletal muscle (4, 5).
In muscle, BCAAs serve a variety of essential purposes. Most importantly for physique and performance athletes, BCAAs are the building blocks required for the synthesis of other amino acids and proteins. BCAAs promote protein synthesis, and one particular BCAA, leucine, activates a key pathway in the body (known as
mTOR) that stimulates muscle protein synthesis, or MPS (6).
BCAAs may also promote muscle repair and recovery by decreasing protein breakdown, which could have a positive impact on DOMS, or delayed-onset muscle soreness. Two different systematic reviews on BCAA supplementation showed that they had potential for alleviating muscle damage, when consumed in high
doses for a consistent amount of time prior to exercise, especially when compared to passive recovery alone(7,8).
Another reason BCAAs are of interest to athletes is that their supplementation may support improved
exercise performance. A systematic review of BCAAs effects on exercise found that they reduced markers associated with fatigue and muscle soreness like lactate levels, ammonia levels, and creatine kinase levels(9). In other words, BCAAs can help build, maintain, and repair muscle, and can be thought of as beneficial to your muscle growth and workout recovery
WHEN SHOULD I TAKE BCAAS?
Research across the past 50-plus years has provided very solid evidence that ingesting specific amino acids(i.e., BCAAs) around resistance exercise augments the rate of skeletal muscle protein synthesis to a greater extent than either amino acid supplementation or resistance exercise alone (1, 2). More specifically, consuming BCAAs in scientifically researched and evidence-based quantities before, during, and after your resistance exercise stimulates an increase in MPS, helping you build muscle, and is even necessary to shift net muscle protein balance—defined as muscle protein synthesis minus muscle protein
breakdown (MPB)—from negative to positive, or to a state of growth (anabolism) (3).