What are they?
The most popular amino acid supplement comprises the branched-chain amino acids (BCAAs): valine, leucine and isoleucine. These three amino acids make up one-third of muscle proteins.
What do they do?
The theory behind BCAA supplements is that they can help prevent the break down of muscle tissue during intense exercise. They are converted into two other amino acids – glutamine and alanine – which are released in large quantities during intense aerobic exercise. Also they can be used directly as fuel by the muscles, particularly when muscle glycogen is depleted.
What is the evidence?
Studies at the university of Guelph, Ontario, suggest that taking 4g BCAA supplements during and after exercise can reduce muscle breakdown (MacLean et al., 1994). They may help preserve muscle in athletes on a low carbohydrate diet and, taken before resistance training, reduce delayed onset muscle soreness (Nosaka et al., 2006; Shimomura et al., 2006). A study by researchers at Florida State University found that BCAA supplementation before and during prolonged endurance exercise reduced muscle damage. However, similar benefits were obtained following consumption of a carbohydrate drink and it is not clear whether chronic BCAA supplementation benefits performance.
Do I need them?
They probably won’t improve your endurance but will help improve your recovery during hard training periods by reducing muscle protein breakdown and post exercise injuries.