Amino acids are needed for building protein and any sportsperson, fitness enthusiast, bodybuilder, weight or strength trainer will make it quite clear why they take any supplement that helps build or replace muscle. There are 20 amino-acids needed for protein synthesis  but some are more important than others when it comes to this particular aspect of physiology after intense exercise.  

If you are looking for a supplement that will reduce muscle soreness and and metabolic recovery then look no further than the branched-chain amino-acids or BCAAs. These are leucine, isoleucine and valine. These three are used by muscle during exercise which gives them a unique position in energy metabolism compared to other amino-acids. In some cases, sports people supplement with just leucine but with vigorous exercise all these soon become depleted. It is worth stating from the outset that for many of us, if we eating plenty of protein then the need for supplementing with BCAAs makes little sense. Protein contains plenty of BCAAs and for many are unnecessary but there are those who swear by them.  

There is also a fair bit of clinical evidence to support their use too. They have quite a track record of use and were seriously considered from the late eighties onwards (Lemon, 1991). They also have quite a track record of use and were seriously considered from the late eighties onwards (Lemon, 1991). The whole subject of BCAA biochemistry in metabolism has been reviewed very recently (Zhang et al., 2017) where they give a very good account of how BCAAs impact in all sorts of human physiology (worth checking out !) 

Leucine might be considered to act like a hormone as it activates muscle protein synthesis directly (Norton and Layman, 2006). In fact these three amino acids are key to regulating protein metabolism as well as having a key role in protein synthesis and its regulation.

Clinical studies showed that when compared to a placebo, a daily intake of 20g of BCAAs with half taken in the morning and then evening for a week before intensive exercising helped reduce muscle soreness by 30%. Markers for muscle damage were also reduced by 22% and there was improved muscle performance during the recovery phase (Howatson et al., 2012).

Dosing & Timing

Consume at least 2.5g of leucine per meal on average four times per day. This promotes a better weight loss, more fat loss and improved retention of muscle performance in the recovery phase. Similar studies show a high leucine content in the diet impacts on better control of blood glucose levels (Zhang et al., 2007).


BCAAs are best used in a pre-workout drink like a protein shake although we know of some who take these alone when they don’t want protein as well. The feeling is that it is easier to deal with being a much lighter softer load before intense exercise. Understood ! 

Endurance athletes can also be helped using BCAAs. Apparently there is plenty of clinical and anecdotal evidence suggesting back packers, marathon runners or anybody involved with prolonged exercise who benefits from supplementation. Cyclists for example were shown to benefit from high levels of BCAA ingestion when they were engaging in sprints during endurance racing (Kephart et al., 2016). This was a study into performance at the School of Kinesiology in Auburn University, USA. BCAAs also appear to ‘blunt’ the neutrophil response to intense cycling training. This suggests an immune function benefit when they are involved in a long cycling season. We have already commented on the benefits for basketball players.

Controlling Body Fat

There is some evidence that if we increase our protein intake and reduce our carbohydrate intake at the same time, we can enhance weight loss, lose more body fat without sacrificing muscle or rather lean body mass (Layman et al., 2003; Noakes et al., 2005). It is not a stretch of the imagination to look at BCAAs as a useful way of reducing obesity in the same way protein ingestion might and in that same way also control diabetes by minimising insulin resistance or controlling glucose tolerance (Kainulainen et al., 2013). All these additional benefits help with improving general health and fitness. 

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Howatson, G., Hoad, M., Goodall, S., Tallent, J., Bell, P. G., & French, D. N. (2012). Exercise-induced muscle damage is reduced in resistance-trained males by branched chain amino acids: a randomized, double-blind, placebo controlled study. Journal of the International Society of Sports Nutrition, 9(1), 20

Kainulainen, H., Hulmi, J.J., Kujala, U.M. (2013) Potential role of branched-chain amino acid catabolism in regulating fat oxidation. Exerc. Sport Sci. Rev. 41 pp. 194–200.

Kephart, W.C., Wachs, T.D., Mac Thompson, R., Mobley, C.B., Fox, C.D., McDonald, J.R., et al. (2016) Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists. Amino Acids. 48 pp. 779–89

Layman, D.K., Boileau, R.A., Erickson, D.J., Painter, J.E., Shiue, H., Sather, C., et al. (2003) A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J. Nutr. 133 pp. 411–7.

Lemon, P.W. (1991) Protein and amino acid needs of the strength athlete. Int. J. Sport Nutr. 1 pp. 127–45

Noakes, M., Keogh, J.B., Foster, P.R., Clifton, P.M. (2005) Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am. J. Clin. Nutr. 81 pp. 1298–306.

Norton, L.E., Layman, D.K. (2006) Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J. Nutr. 136:533S–7S.

Zhang, Y., Guo, K., LeBlanc, R. E., Loh, D., Schwartz, G. J., & Yu, Y. H. (2007). Increasing dietary leucine intake reduces diet-induced obesity and improves glucose and cholesterol metabolism in mice via multimechanisms. Diabetes, 56(6), pp. 1647-1654
Zhang, S., Zeng, X., ren, M., Mao, X., Qiao, S. (2017) Novel metabolic and physiological functions of branched chain amino acids: a review. J. Animal Science and Biotechnology 8:10 https://doi.org/10.1186/s40104-016-0139-z