Although heavily marketed in the supplement industry, the science is pretty clear that BCAA supplements are not effective at increasing muscle gains.
By Dr. Adam Gonzalez
SHIFTED’s Chief Scientific Officer
Branched-chain amino acids (BCAA) are one of the most popular supplements on the market due to their role in stimulating muscle protein synthesis. Despite the heavy marketing in the supplement industry and their prevalent use among bodybuilders, studies have consistently failed to show benefits from supplementing with BCAAs (or isolated leucine) on muscle gains.
When combined with a resistance training program, BCAA supplements simply do not offer much. In this article, we will clarify why most experts agree that BCAA supplements are worthless.
What are BCAAs?
Dietary protein is made up of 20 amino acids – 9 of which are essential amino acids (EAAs). EAAs must be consumed in the diet because the body cannot adequately produce them. Only 3 of the 9 EAAs are BCAAs, which include leucine, isoleucine, and valine.
BCAAs (particularly leucine) have clearly been identified as the key regulators of the anabolic response in the muscle following protein intake. For example, leucine has shown to activate anabolic pathways in the muscle and the response is enhanced with the addition of the other 2 BCAAs (isoleucine and valine).
Put simply, the protein that you eat must contain BCAAs to stimulate an anabolic response in the muscle. However, “stimulating” muscle protein synthesis is just part of the anabolic equation. Sustaining a meaningful increase in muscle protein synthesis requires an adequate supply of all EAAs.
Do BCAAs stimulate muscle protein synthesis?
Short answer: Yes.
Supplementing with BCAAs in isolation does increase muscle protein synthesis, however it cannot sustain the response for as long as a complete protein source containing the same amount of BCAAs.
For example, one study showed that the ingestion of 6 grams BCAAs and 30 grams of milk protein (providing ~6 grams of BCAA) both increased muscle protein synthesis in the first 2 hours following ingestion. However, only the complete milk protein was able to keep the anabolic response elevated for up to 5 hours, while the BCAA group rapidly returned to baseline values.
Another study demonstrated that supplementing with ~6 grams of BCAAs increased muscle protein synthesis during the first 4 hours following ingestion. However, studies show that consuming 25 grams of whey protein (which contains ~6 grams of BCAAs) promotes a 50% greater anabolic response as compared to the BCAAs in isolation.
In summary, BCAAs (particularly leucine) serve as the trigger to initiate muscle protein synthesis, yet BCAAs alone cannot induce a sustained and meaningful elevation in the muscle building processes. All 9 EAAs are required to serve as the building blocks for muscle protein synthesis.
Are BCAAs useful?
Short answer: No.
They just don’t meet the hype. This is evidenced by the growing body of literature that has shown no effect of supplementing with BCAAs on muscle strength and hypertrophy when combined with a resistance training program (1, 2, 3, 4, 5, 6). To play devil’s advocate, it’s worth acknowledging that there is some evidence suggesting that BCAA supplements improve aspects of muscle recovery.
However, all these studies compare BCAAs to a placebo (not an EAA or complete protein source). Therefore, it would not be a leap to suggest that any benefits observed in these BCAA studies would be surpassed by a supplement containing the BCAAs as part of a mixture of all EAAs.
What’s the bottom line?
Sparking a robust increase in muscle protein synthesis requires the availability of all EAAs. Therefore, consuming whole proteins containing all 9 essential amino acids is better suited to enhance anabolism compared to BCAAs in isolation. A recent review of the evidence concluded that the current literature does not support the efficacy of supplementation with BCAAs on muscle strength and hypertrophy. Especially when consuming adequate dietary protein (>1.6 grams per kilogram of bodyweight per day), BCAA supplementation offers no benefits on body composition or strength.
SHIFTED will never market isolated BCAAs. Our products will always contain a full spectrum of EAAs to assure you are maximizing your gains.