Branched-chain amino acids (BCAAs) is the name given to three of the nine essential amino acids. BCAAs are sold as a sports supplement to increase muscle synthesis and recovery. Today we answer the question: Should you take BCAAs?
What are BCAAs?
BCAAs or branched-chain amino acids are leucine, isoleucine and valine. They are essential amino acids (EAAs), meaning they cannot be made by our bodies and must be taken from the diet. Unlike other amino acids, BCAAs are not metabolised in the liver (1, 2) but in skeletal muscle (2). They can be oxidised and used as energy (2, 3).
BCAA supplements are commonly used in athletic populations. Most supplements come in powder form and contain a mixture of the 3 BCAAs in a ratio of 2 to 4 leucine to isoleucine and valine. The ratio is usually shown in the product label, for example 2:1:1 indicates the product contains twice as much leucine than the other two amino acids.
Benefits of BCAAs
Common benefits attributed to BCAAs include reducing protein breakdown, helping with muscle recovery, reducing muscle soreness and fatigue (1, 4), and improving muscle energy metabolism (2).
Muscle protein synthesis
BCAAs, in particular leucine, activate a signalling pathway in the body known as mammalian target of rapamycin complex I (mTORC1), which promotes muscle protein synthesis (2, 3, 4, 5). However, leucine cannot work alone and there is evidence to suggest that the synergistic effect of EAAs (BCAAs in particular) and resistance exercise stimulate muscle growth to a greater extent (5).
A small study that investigated the effects of supplements on muscle synthesis pathways found that EAAs were more effective than BCAAs and these were more effective than leucine alone.
This is explained by the fact that muscle protein synthesis requires the availability of all EAAs. If only BCAAs are consumed, the building blocks for new muscle protein must come from protein breakdown. The net result could potentially be a decrease in protein synthesis. However, consuming BCAAs in addition to a complete protein-containing meal may potentiate the anabolic effect of the protein alone (6).
BCAA supplementation has been associated with a reduction in the perception of muscle soreness following intense resistance exercise (1). Similar results have been found for endurance sports (4).
BCAAs degradation produces glutamate, which is used to produce glutamine. Glutamine can be taken in by inflammatory cells, which may be the mechanism behind reduction in muscle soreness (1).
Markers of muscle damage such as creatine kinase (CK) rise post-exercise, which is mitigated when consuming BCAAs (1).
Effective and safe doses
Results from studies are not conclusive. Below are some documented cases where BCAA supplementation has been found effective:
- people who are not consuming adequate levels of protein (1)
- high doses of BCAAs (greater than 200 mg per kilogram per day) taken frequently (2 or more daily doses) for a long period of time (more than 10 days) (2)
- for endurance exercise: 50 to 200mg per kg per day of a BCAA mixture of 2-3:1:1 (4)
The maximum safe dose seems to be 550mg per kilogram per day (4).
BCAAs and insulin resistance
Data from animal studies have shown that BCAAs metabolism induces insulin resistance through complex biochemical processes. However, in athletic populations, BCAAs promote glucose uptake and skeletal muscle synthesis. This mechanism negates the potential for insulin resistance, resulting in net insulin sensitivity in the athletic population (3).
BCAA supplements in Australia
There are many national and international sports supplements manufacturers offering BCAAs or formulated supplements containing them. If you are a competing athlete or get tested for banned substances for work reasons, look for tested products.
At the moment of writing, HASTA-certified BCAA supplements include:
You can also check for tested supplements at Informed-Sport.
Should you take BCAAs?
The evidence in favour of BCAAs supplementation indicates that it may help with muscle recovery and perceived soreness after intense exercise but not with muscle function or performance.
Therefore, you can try a BCAA supplement if you have already covered your recovery bases (including adequate energy, protein and micronutrient intake, hydration, stretching and sleep) and still have indications of incomplete muscular recovery, such as soreness, fatigue or injury.
Read labels and go for products that have been batch tested if you are a competitive athlete or your job tests for banned substances.
As always, ask a sports dietitian before trying a new supplement.
- VanDusseldorp TA, Escobar KA, Johnson KE, Stratton MT, Moriarty T, Cole N, et al. Effect of Branched-Chain Amino Acid Supplementation on Recovery Following Acute Eccentric Exercise. Nutrients. 2018;10(10).
- Fouré A, Bendahan D. Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review. Nutrients. 2017;9(10).
- Shou J, Chen PJ, Xiao WH. The Effects of BCAAs on Insulin Resistance in Athletes. Journal of nutritional science and vitaminology. 2019;65(5):383-9.
- Salinas-García ME, Martínez-Sanz JM, Urdampilleta A, Mielgo-Ayuso J, Norte Navarro A, Ortiz-Moncada R. [Effects of branched amino acids in endurance sports: a review]. Nutricion hospitalaria. 2014;31(2):577-89.
- Moberg M, Apró W, Ekblom B, van Hall G, Holmberg HC, Blomstrand E. Activation of mTORC1 by leucine is potentiated by branched-chain amino acids and even more so by essential amino acids following resistance exercise. American journal of physiology Cell physiology. 2016;310(11):C874-84.
- Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30.
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