Are BCAA Supplements Useful?

September 17, 2018 ,

In the last few years, BCAA supplements (Branched-Chain Amino Acids) have become very popular with people that workout. They take them with the intention of preventing muscle breakdown, stimulating muscle mass gain, promoting muscle recovery and reducing fatigue during endurance training. But are they really useful? Let’s break it down together!

What are BCAAs?

Protein are made of amino acids, which constitute their base structural units. There are nine essential amino acids, of which the body is not able to create by itself and must necessarily find them in food to meet its needs. Branched-chain amino acids (BCAA) are composed of three of those essential amino acids which are leucine, isoleucine and valine. It is important to know that BCAAs are abundant in our diet. A tablet of BCAAs is composed on average of 100mg of valine, 50mg of isoleucine and 100mg of leucine. For comparison, a 100g chicken breast is equivalent to 7 tablets of BCAAs, while 4 tbsp of peanut butter equals 11 tablets of BCAAs.

Are BCAAs useful for people who exercise?

It has been suggested that supplementation with BCAAs could potentially promote muscle mass gain, decrease protein breakdown in the muscle, and delay fatigue in endurance events. However, all studies were not able to demonstrate the effects of BCAAs on performance or on delay in the onset of fatigue and, therefore, prolongation of the duration of exercise. It should be known that muscle synthesis requires the presence of all the essential amino acids (all 9). Having a large amount of BCAAs will not allow synthesis if the other amino acids are not available. In addition, taking such supplements may be cause undesirable effects such as the inhibition of absorption of other amino acids, water retention in the stomach and gastrointestinal disorders. Many athletes take a BCAA supplement during weight training exercises, thinking that it will prevent the breakdown of muscle mass. However, during physical activity, carbohydrates are the best source of energy for the muscles. Thus, it is rather a lack of carbohydrates that could cause the degradation of proteins to provide the muscles with the missing energy, thus decreasing performance, since proteins are not an effective source of energy for the muscles.

Can an excess of BCAAs be harmful?

While BCAAs may be useful in conditions where the energy balance is negative, which means for people who are unable to eat enough food to meet their protein needs (for example people who suffer from malnutrition), this does not seem to be the case when the energy intake is sufficient or excessive. In some studies, increased blood levels of BCAAs have been associated with an increased risk of type 2 diabetes and cardiovascular disease. It appears that overeating in obese individuals may promote an increase in circulating BCAAs. Studies in obese or cancer rats suggest that excessive BCAA consumption may cause insulin resistance and muscle lipid accumulation, as well as promote tumor growth.

Take home message

In conclusion, yes BCAAs are important for building muscle, but they can be easily found in high quality proteins such as meat, poultry, fish, eggs, dairy products, combinations of vegetable proteins and even whey protein isolate (whey protein powder), which already contain them naturally. BCAAs have no added value compared to complete proteins. In this sense, if you have an optimal protein intake (20 to 30g of protein per meal), taking a BCAA supplement will not bring you additional benefits.


Updated: September 4, 2019


Kathryn Adel
Kathryn completed degrees in kinesiology and nutrition, as well as a Masters in Sports Nutrition. She is a member of OPDQ and of the Academy of Nutrition and Dietetics. She ran track and cross-country at a national level. Kathryn specializes in sports nutrition, weight loss, diabetes, as well as heart and gastrointestinal health. Kathryn is experienced with the low FODMAP diet and she completed the Monash University low FODMAP dietitian's training.

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