Amino acids are the building blocks of protein. There are nine essential amino acids in total, but scientists have found that there is a key trio that helps you maintain muscle. The three Branched Chain Amino Acids (BCAA’s) are Leucine, Isoleucine, and Valine. This trio has a unique role in various muscular processes. Most importantly of these roles, they provide a fuel source to working muscles and a crucial role in decreased protein breakdown. They are unique in that, unlike other amino acids, upon absorption, they are not degraded in the liver and are transported directly to the muscle.

Generally Branched Chain Amino Acids are found in protein-rich foods, but amounts vary widely with differing protein sources. The highest food sources are Whey Protein, Milk and Dairy, Beef, Salmon, and Soy. Some researchers don’t see value in supplementing with BCAA’s if your diet is rich in protein.

“Bottom line is if you are taking in adequate protein, then BCAAs are a complete waste of money,” says protein researcher, Stuart Phillips, Ph.D., of McMaster University.

BCAA’s are found in many foods and are a component of a healthy diet, therefore safety does not permit much concern for healthy individuals. They are also essential amino acids, meaning we need to take them in since our bodies cannot produce them.


Of the 3 BCAA’s, Leucine is responsible for initiating protein synthesis, therefore it may be the most essential of essential amino acids. BCAA’s also enhance insulin sensitivity and are incredibly important in providing glucose to working muscles during sustained activity.

A study published in the Journal of the International Society of Sports Nutrition found that individuals were able to maintain lean body mass when supplementing with BCAAs during a calorie-restricted diet:

Background: Athletes and active adults many times have the goal of improving/maintaining fitness while losing weight and this is best achieved by caloric restriction in combination with exercise. However, this poses a risk for lean tissue loss, which can limit performance. Thus, the purpose of this study was to determine the effectiveness of a branched-chain amino acid (BCAA) supplement, in conjunction with heavy resistance training and a carbohydrate caloric-restricted “cut diet” on body composition and muscle fitness.

Results: These results show that BCAA supplementation in trained individuals performing resistance training while on a hypocaloric diet can maintain lean mass and preserve skeletal muscle performance while losing fat mass.

Taking in roughly three grams of Leucine has been shown to maximally stimulate protein synthesis, therefore a source supplying three grams pre-workout, and three-six grams post-workout is recommended. The post-workout recommendation is higher because exercise increases Leucine oxidation. A general daily recommended intake of BCAA’s is 6-15 grams per day total.

As with creatine, it is beneficial to take them with a fast digesting carbohydrate source, as insulin increases their uptake into the muscle. Insulin also plays an important role in protein synthesis. Although Leucine can be purchased and taken alone, it is recommended to take all three Branched Chain Amino Acids together, as taking just one could create an imbalance. A ratio of 2:1:1 Leucine/Isoleucine/Valine, respectively, is recommended.

Lastly, it should be noted that BCAA’s are important, but are not an end all replacement to the intake of the other amino acids and a healthy, complete diet.