The acronym "BCAA" stands for branched-chain amino acids, a term used to refer to three essential amino acids:
The descriptor “branched-chain” refers to the unique molecular structure of the three BCAA amino acids.
Much of the interest in the benefits of BCAA dietary supplements has been driven by athletes who believe these amino acid supplements can help to build muscle mass, accelerate muscle recovery, diminish muscle soreness after intense activity, improve exercise performance, increase energy production, and more. There’s even some evidence that the effects of BCAA supplementation include more balanced blood sugar levels and the facilitation of fat loss.
Read on to learn about the science behind the much-hyped beneficial effects of BCAA amino acids, including crucial information on how to maximize the impact of increased BCAA intake.
What You Should Know About BCAA Amino Acids
Of the 20 amino acids the human body uses as building blocks to make proteins, nine are deemed essential because the body cannot produce them, meaning they must be obtained from the food a person eats or from targeted supplementation. As mentioned above, the three BCAAs, leucine, isoleucine, and valine, are essential amino acids. If you wish to access their remarkable benefits, you must provide your body with an adequate supply from your diet or from supplements.
Many healthy, high-protein foods naturally contain BCAAs, such as:
- Red meat, poultry, fish and other seafood
- Eggs, milk, cheese, and other dairy products
- Nuts and seeds
- Soybeans and products made from soy such as tofu and tempeh
- Legumes like beans, peas, and lentils
8 Scientifically Validated Benefits of BCAAs
The popularity of BCAA supplementation is supported at least in part by diligent research into the proposed benefits of these amino acids.
One of the best-known and most agreed-upon benefits of BCAAs is their ability to increase muscle protein synthesis and decrease muscle protein breakdown, thus encouraging increased muscle growth.
However, the benefits of BCAAs are not limited to bodybuilders and those seeking to enhance the effects of their workouts. Read on to learn about the science behind eight effects of BCAA supplementation.
1. Build Muscle Mass
One of the famous uses for BCAAs supplements is as a means to build muscle mass.
Leucine, the most potent of the BCAAs, activates the rapamycin complex (mTOR) signaling pathway, thereby stimulating muscle protein synthesis. According to a study published in the Journal of Nutrition, leucine has an impressive anabolic effect on skeletal muscle, which leads to impressive muscle-building results.
A study published in Frontiers in Physiology found that when people took BCAAs post-workout, they had a 22% increase in muscle protein synthesis compared to those who consumed a placebo drink.
However, even more impressive results ensue when leucine and the other BCAAs are ingested in combination with all the essential amino acids necessary for muscle building. Based on the findings of a study published in the American Journal of Physiology-Cell Physiology, taking BCAAs along with the other essential amino acids can result in at least 18% greater muscle-building activity.
2. Improve Exercise Performance
Yet another benefit of BCAAs many people find appealing is their ability to improve exercise performance.
A study published in the Journal of Exercise Nutrition & Biochemistry found that taking pre-workout BCAA supplements produced significant changes to substances linked to energy metabolism and physical fatigue.
The study authors concluded that, thanks to their demonstrated ability to lower concentrations of serotonin, a neurotransmitter that produces a fatiguing effect, BCAAs can then produce a cascading effect that limits the influence of other substances related to fatigue and energy production. "Therefore, the intake of the BCAA is presumed to help contribute to enhancing exercise performance," the authors stated.
3. Minimize Mental and Physical Fatigue
As noted above, the physiological basis for BCAAs' ability to enhance exercise performance has to do with their effect on substances related to fatigue and energy production.
A 2016 study published in the Journal of Sports Science and Medicine showed that when endurance runners took a BCAA supplement, their performance significantly improved.
The researchers who conducted the study attributed this effect to the impact BCAAs have on serotonin, which as discussed in the previous section, is a neurotransmitter that promotes fatigue during exercise. BCAAs inhibit the production of serotonin during exercise, thereby helping to reduce fatigue so endurance athletes can run faster and go longer.
4. Reduce Muscle Damage and Accelerate Muscle Recovery
A study published in the Journal of the International Society of Sports Nutrition also showed that BCAA supplements can reduce muscle damage and accelerate recovery when taken before and after resistance exercise.
“The present study has shown that BCAA administered before and following damaging resistance exercise reduces indices of muscle damage and accelerates recovery in resistance-trained males," the study authors wrote. "It seems likely that BCAA provided greater bioavailablity of substrate to improve protein synthesis and thereby the extent of secondary muscle damage associated with strenuous resistance exercise.”
A separate study published in The Journal of Sports Medicine and Physical Fitness shed light on the mechanism by which BCAAs are able to reduce the markers of muscle damage. It appears that they can decrease levels of two prominent enzymes that contribute to muscle breakdown—creatine kinase and lactate dehydrogenase.
5. Alleviate Muscle Soreness
BCAA amino acids’ influence on muscle soreness was demonstrated by a study from the International Journal of Sport Nutrition and Exercise Metabolism.
The crossover, double-blind study looked specifically at the effect of BCAAs in delayed-onset muscle soreness (DOMS).
Participants who took BCAAs prior to their workouts experienced significantly lower levels of soreness than those who took a placebo. This translated to improved muscle force on the following day as well.
6. Regulate Blood Sugar Levels
More research needs to be done to confirm this BCAA benefit, but it appears that taking these amino acids can help you maintain balanced, healthy blood sugar levels.
Studies done with rats indicate that isoleucine may have the most pronounced impact on insulin secretion of the three BCAAs, though leucine also seems to play a role in increasing the uptake of sugar by muscle tissue, a process which subsequently lowers blood sugar levels.
At least one study with human participants also indicated a beneficial effect of BCAAs on blood sugar levels.
7. Support Weight-Loss Efforts
The ability of BCAAs to propel lean muscle growth seems to be linked to the encouragement of fat loss.
A 2009 randomized, double-blind study found that BCAA supplementation, paired with a resistance-training program, resulted in a greater decrease in percent body fat and increase in lean muscle mass than either whey protein or a carbohydrate-based sports drink.
Study participants, all of whom had previous strength-training experience, were divided into three groups. The first took 14 grams of BCAAs, the second 28 grams of whey protein, and the third 28 grams of a carbohydrate-based sports drink. All three groups completed the same 8-week training regimen. At the study's conclusion, participants in the BCAA group gained an average of 4 kilograms of lean mass and lost an average of 2 kilograms of body fat.
8. Improve Liver Function
Last but certainly not least, there's some evidence indicating that BCAA supplementation can improve liver function.
A 2017 study looked at the effect of BCAAs on the symptoms of patients with advanced liver cirrhosis over the course of 6 months. The results of this nationwide, multi-center, retrospective, observational, cohort study conducted by a preeminent team of Korean researchers showed that the long-term use of BCAAs had pronounced benefits for individuals with liver disease.
At the study's conclusion, the Model for End-Stage Liver Disease (MELD) test scores of participants who took BCAAs had improved considerably in comparison to those in the placebo group. MELD scores determine the degree of severity of a person's liver disease based on blood levels of substances like creatinine and bilirubin.
In addition to the health benefits mentioned above, medical professionals have used BCAAs to treat:
- Lou Gehrig’s disease
- Brain conditions related to liver disease such as chronic hepatic encephalopathy and latent hepatic encephalopathy
- A genetic disease called McArdle’s disease
- A movement disorder called tardive dyskinesia
- Spinocerebellar degeneration
- Poor appetite in cancer and kidney failure patients
- Slow muscle wasting in bedridden individuals
How to Get the Best Results from BCAA Supplementation
Though BCAAs are one of the most popular supplements in the fitness community, they are also some of the most misused. BCAA amino acids can, without a doubt, help build muscle and boost performance, but when taken on their own, the much-coveted results associated with their use will be dampened at best and entirely absent at worst.
That's because taking a BCAA supplement containing solely the three BCAA amino acids (leucine, isoleucine, and valine) will have minimal effect on protein synthesis. In order for your body to build complete proteins it needs an infusion of all the essential amino acids in their appropriate concentrations. Taking only a BCAA supplement disrupts the balance of the amino acid pool. Rather than reaping the benefits known to be associated with an increased intake of leucine, isoleucine, and valine, you're likely to see only minimal gains, if any at all.
When paired with a complete amino acid complex, however, the results of BCAA supplementation can be quite dramatic. To learn more about best practices for BCAA supplementation, read this article by Dr. Robert Wolfe.