BCAAs are essential amino acids that bodybuilders and athletes use to increase power output, reduce fatigue, and improve fat loss. However, excessive BCAA usage can have negative side effects, such as increasing the risk for type 2 diabetes and other conditions. Read on for further details on the potential effects of BCAA and their correct dosage.

What Are BCAAs?

There are three BCAAs: leucine, isoleucine, and valine, which are all essential amino acids – not produced by the body but needed for survival [1, 2].

BCAAs are the largest collection of amino acids in the body, accounting for up to 35% of muscle proteins. These amino acids (especially leucine) stimulate protein production in the muscles, possibly helping with muscle building and recover [1, 3, 4].

They also seem to promote sugar storage in the muscles. In animal studies, BCAAs (especially isoleucine) promoted blood glucose uptake into the muscles while blocking muscle carbohydrate (glycogen) breakdown [5, 6].

Normally, BCAAs are excreted rapidly. BCAA intermediates can be toxic at high concentrations, so functional BCAA breakdown is vital. Because BCAAs are broken down in the muscle rather than in the liver, they are thought to help produce energy during exercise [1, 2, 7].

BCAA formulas have been on the market since 1996, mainly for treating liver diseases such as cirrhosis and hypoalbuminemia [8].

Nowadays, BCAAs are mainly used by bodybuilders for exercise purposes, to increase energy, and boost protein synthesis (especially leucine) [1].

Snapshot

Proponents

• Essential amino acids
• Approved for nitrogen loss
• May help recover from exercise and increase body lean mass
• May help with liver cirrhosis and its complications

Skeptics

• Unclear effects on exercise performance
• Excessive supplementation may trigger type 2 diabetes and ALS
• May cause high ammonia levels
• May interfere with the uptake of other essential amino acids
• Not recommended in people with insulin resistance, McArdle’s disease, and maple syrup urine disease

Health Benefits

Effective for:

Nitrogen Loss

An injectable 4% BCAA formulation (BranchAmin) is approved by the FDA as a nitrogen source in people with severe nitrogen loss due to poor protein absorption or septic shock [9].