Branched-chain Amino Acid Supplementation for Athletic Performance

Branched-chain Amino Acid Supplementation for Athletic Performance

Branched chain amino acids

Branched-chain amino acids (BCAA) have been available as a dietary supplement for potentially improving athletic performance for several years.  What are branched-chain amino acids?

‘Branched-chain’ refers to their chemical structure which includes non-linear aliphatic side chains.  BCAA are considered essential amino acids.  This means that your body cannot produce them, so they have to be consumed in your diet.  Normal diets consist of 15-20% BCAA and dairy products are particularly high in BCAA content.

Does supplementation with branched-chain amino acids work?

A recent study was published in the Journal of Strength Condition Research (Sharp et al, 2010) which studied the effect of supplementation with branched-chain amino acids during a short period of high-intensity resistance training.  Subjects consumed 6 grams/day of BCAA for a duration of 3 weeks while engaging in resistance training exercises.

Results of the study:

“Serum testosterone levels were significantly higher (p < 0.001), and cortisol and creatine kinase levels were significantly lower (p < 0.001, and p = 0.004, respectively) in the BCAA group during and following resistance training.”

Study conclusions:

“These findings suggest that short-term amino acid supplementation, which is high in BCAA, may produce a net anabolic hormonal profile while attenuating training-induced increases in muscle tissue damage.”

Study limitations:

  • First, this study even with the cross-over design had a relatively small sample size of just 8 participants.
  • Secondly, this study excluded participants who consumed more than 0.8g/kg of protein per day.  Most athletes consume larger quantities of protein than this amount.
  • Lastly, this study only used a dose of 6 grams of BCAA per day which the study authors conceded was half the amount used in previous research.

Given that most whey protein supplements have a fairly high percentage of BCAA, it’s certainly within reason to question whether these results are unique to branched-chain amino acid supplementation.  In short, it’s conceivable that you would probably get the same results from whey protein supplementation.

Does branched-chain amino acid supplementation improve running performance?

A previous study by researchers in Japan (Koba et al, 2007) found that consuming a drink containing BCAA (0.4% BCAA) during a 25km run reduced blood lactate levels compared to an iso-calorie placebo.

Study author conclusions:

“Maintaining the blood BCAA level throughout a long distance run contributes to a reduction in the LDH release and, therefore, the effect of BCAA supplementation is suggested to reduce the degree of muscle damage.”

The same study group also found that a similar protocol of  BCAA (0.8% BCAA in a 3.5% carbohydrate solution; 2,500 mL/day) consumed by long-distance runners during training periods reduced muscle soreness and fatigue sensation (Matsumoda et al, 2009).

Does branched-chain amino acid supplementation work better than whey protein with casein?

Again, in another previous study, researchers in Texas (Kersick et al, 2006), published the results of a study comparing different types of protein supplementation on body composition and strength during 10 weeks of resistance training.

The study authors compared four groups:

  1. 48 g per day (g.d(-1)) carbohydrate placebo (P)
  2. 40 g.d(-1) of whey protein + 8 g.d(-1) of casein (WC)
  3. 40 g.d(-1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5 g.d(-1) L-glutamine (WBG).

The study authors concluded:

“Significant increases in 1RM bench press and leg press were observed in all groups after 10 weeks.

In this study, the combination of whey and casein protein promoted the greatest increases in fat-free mass after 10 weeks of heavy resistance training.”

Amino-acid mixture improves training efficiency?

Another Japanese study (Ohtani et al, 2006) found that supplementation with an amino acid mixture (BCAA, glutamine, and arginine) during athletic training (30/60/90 days) had the following effect:

“A dose-response study of the amino acid mixture at 2.2, 4.4, and 6.6 g/d for 1 mo showed that at the highest dose, indices of blood oxygen-carrying capacity were increased and those of muscle damage were decreased at the end of the trial.”


  1. Sharp CP, Pearson DR.  Amino acid supplements and recovery from high-intensity resistance training.  J Strength Cond Res. 2010 Apr;24(4):1125-30.
  2. Koba T, Hamada K, Sakurai M, Matsumoto K, Hayase H, Imaizumi K, Tsujimoto H, Mitsuzono R.  Branched-chain amino acids supplementation attenuates the accumulation of blood lactate dehydrogenase during distance running.  J Sports Med Phys Fitness. 2007 Sep;47(3):316-22.
  3. Kerksick CM, Rasmussen CJ, Lancaster SL, Magu B, Smith P, Melton C, Greenwood M, Almada AL, Earnest CP, Kreider RB.  The effects of protein and amino acid supplementation on performance and training adaptations during ten weeks of resistance training.  J Strength Cond Res. 2006 Aug;20(3):643-53.
  4. Ohtani M, Sugita M, Maruyama K.  Amino acid mixture improves training efficiency in athletes.  J Nutr. 2006 Feb;136(2):538S-543S.
  5. Matsumoto K, Koba T, Hamada K, Sakurai M, Higuchi T, Miyata H. Branched-chain amino acid supplementation attenuates muscle soreness, muscle damage and inflammation during an intensive training program.  J Sports Med Phys Fitness. 2009 Dec;49(4):424-31.
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