Our results show that the common practice of taking combined BCAA plus CHO supplements will not result in maximal stimulation of muscle synthesis. Instead, a sufficient amount of the full complement of amino acids is necessary for maximal stimulation of muscle protein synthesis following exercise. Athletes interested in enhancing muscle growth with training should not rely on combined BCAA and carbohydrate supplements alone.
Dr Oliver Witard, Senior Lecturer in Exercise Metabolism & Nutrition
29 June 2023
BCAA supplements not most effective type of supplements for stimulating muscle growth
New research suggests that BCAA supplements aren’t as effective as supplements with all nine essential amino acids in stimulating muscle growth for athletes, bodybuilders or gym-goers.
Amino acids (AAs) are the individual molecules that are used to build proteins. As such, they’re an essential component of the body and nutrient group in the diet. Out of the 20 amino acids, there are nine ‘essential amino acids’ that the body cannot make by itself. Therefore, they’re classified as essential as they need to be acquired through the diet.
BCAA supplements contain three of the nine essential amino acids: leucine, valine and isoleucine. They’re commonly used by athletes or gym enthusiasts to build muscle due to the prevalence of leucine which triggers the metabolic process for creating proteins thus growing the muscle.
However, some research has questioned their effectiveness. A recent publication led by Dr Oliver Witard found that, while they did have a stimulatory effect, BCAAs weren’t as effective as protein sources with all nine essential AAs.
To further investigate the effectiveness of BCAAs, the authors combined them with carbohydrates found in commercial BCAA-supplements. These are recommended to replenish the carbohydrate stores in muscle cells during recovery, and the authors decided to investigate whether it had an impact on the development of muscles post-exercise.
The authors gave supplements with a BCAA-carbohydrate combination to a group of experienced weightlifters immediately after their gym sessions.
The findings, published in the International Journal of Sport Nutrition and Exercise Metabolism, shows how supplements with a mix of BCAAs and carbohydrates stimulated muscle building after weight-lifting exercises. However, a treatment with all nine essential AAs will promote a muscle building response that is twice as strong as the BCAA supplements.
This result is consistent with a previous study by the same authors on male weightlifters consuming just BCAA supplements, showing that they weren’t as effective as supplements with all nine essential amino acids.
With this combined research, the authors argue that BCAA supplements are not the best choice for weight training. They recommend supplements with all the essential amino acids in their place and recommend athletes and gym-goers not rely exclusively on BCAA supplements.
The authors are looking to conduct further studies to determine the optimum dose of BCAAs for people in a range of different population subgroups including females, older adults and people who exercise in high altitudes like military personnel.
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Senior Lecturer in Exercise Metabolism & Nutrition