Branched chain amino acids, or BCAAs, are one of the most powerful supplements you can take for muscle recovery. These three compounds–leucine, isoleucine, and valine–form the building blocks of muscle fibers, and research shows that taking BCAAs as a supplement can boost your strength gains and speed your recovery after tough sessions in the gym. Want to make the most of your BCAA supplement? Read on to find out how to use the key benefits of BCAAs to your advantage.
1. BCAAs are a major building block for muscle fibers
Amino acids are your body’s basic ingredients for forming all of the proteins in your body. They are the most basic building blocks of life.
Among all amino acids, three of them are special—these are the branched chain amino acids, or BCAAs.
A scientific paper published in 2006 by Eva Blomstrand and others at the Karolinska Institutet in Sweden describes how branched chain amino acids boost your body’s muscle-building response to exercise (1).
According to scientific research, taking BCAAs soon after an endurance or resistance workout (i.e. cardio or weights) causes your body to activate its muscle-building pathways more strongly, increasing protein synthesis and boosting strength.
One study cited by Blomstrand et al. showed that a direct branched chain amino acid infusion after doing quadricep raises on a weight machine had a strong effect on three signaling pathways associated with muscle building.
Additional scientific evidence suggests that branched chain amino acids can reduce the breakdown of muscle fibers during exercise and decrease post-workout soreness, which is why BCAAs are found in pre and post workout drinks.
2. BCAAs can reduce soreness
A paper published in the Journal of Nutrition by Yoshiharu Shimomura and other researchers in Japan outlines an experiment in which branched chain amino acids had a substantial effect in reducing soreness in the days following a squat workout (2).
In a placebo-controlled trial, the scientists found that a 5 gram BCAA supplement taken before the squatting protocol reduced soreness over the course of four days when compared to a placebo. The critical point here is that the BCAA supplement was taken prior to the exercise.
Though the exact mechanism by which it prevents muscle soreness is unclear, Shimomura et al. hypothesize that branched chain amino acids reduced the actual breakdown of proteins in the muscles, while leucine in particular increases your production of muscle proteins after a workout.
Because leucine (which is itself one of the three branched chain amino acids) does “double duty” as both a stimulant for protein synthesis and a preventative factor against protein breakdown, BCAA supplements tend to supply relatively more leucine than isoleucine or valine, the two other branched chain amino acids.
3. It’s unclear what the best BCAA ratio is, but your BCAA supplement should contain all three
There are no solid comparative clinical trials on what the optimal ratio is—there are studies that show, for example, that supplements with a 2:1:1 leucine:isoleucine:valine ratio perform better than a placebo (a supplement containing no BCAAs at all), but nothing comparing, say, a 3:1:1 ratio to a 2:1:1 ratio.
The 2:1:1 ratio appears to trace its origins to the work of Dr. Francesco Saverio Dioguardi at the University of Milan, who was among the first to use branched chain amino acids to treat liver disease (3).
After studying the absorption characteristics of the three branched chain amino acids, he developed, ad hoc, the 2:1:1 ratio as his best guess for an optimal ratio.
As these things tend to go, this ratio was quickly enshrined as the optimal one.
It should be pointed out that the 2:1:1 ratio does seem to work pretty well—otherwise there wouldn’t’ be so many studies supporting it—but there isn’t a reason to believe it’s the only ratio that will work.
On the other hand, it’s important to remember that isoleucine and valine are important, too, so if you go too far in one direction (like taking a BCAA supplement that’s loaded up with lots of leucine but very little isoleucine and valine), that is not optimal.
4. BCAAs may help protect your heart
Much of the scientific literature on branched chain amino acids focuses on their ability to protect and repair muscle tissue, but it’s important to remember that your heart is a muscle too.
New research suggests that getting enough BCAAs can help protect your heart as well as your skeletal muscles. A scientific study published in 2016 in the journal Circulation highlighted the role that BCAAs play in repairing and protecting heart tissue (4).
The article notes that most research on heart tissue focuses on the role of fats and carbohydrates, so the role of BCAAs was less well-characterized. This study was able to demonstrate that an adequate supply of BCAAs can protect heart tissue after it is stressed, as occurs in heart failure.
They targeted BCAA levels by knocking out a specific gene, demonstrating that mice with BCAA catabolism suffered an increased amount of oxidative damage in the mitochondria in their heart tissue.
Though it’s not the same level of evidence as a controlled trial of BCAA supplements in humans with heart disease, the mechanism of staving off muscle damage does make sense given what we know about the other effects of BCAA on muscle tissue. Taking a BCAA supplement may well protect your heart as well as your leg and arm muscles.
5. BCAAs can boost your immune response after a tough exercise session
Difficult workouts are hard on your body—that should come as no surprise. In addition to the soreness and a transient decrease in muscle strength that follows a hard gym session, your immune system takes a beating too.
Fortunately, new research suggests that taking a BCAA supplement can help keep your immune system in good shape even after a hard workout. A study published in 2016 in the journal Amino Acids examined the effects of a ten-week BCAA supplementation on a group of trained cyclists (5).
The supplementation routine, which used a pretty heft twelve-gram per day dosage at a 3:1:2 ratio of leucine, isoleucine, and valine, was given to half of the subjects in the study, while the other half received a placebo. The researchers found that the BCAA supplement improves sprint performance, which would make sense based on what we know about BCAAs and their ability to stimulate muscle growth and repair.
However, the BCAA supplement group also experienced no increase in white blood cells, while the placebo group did. The research team interpreted this finding to mean that the BCAA supplement was boosting the immune function of the cyclists taking the BCAAs, while the cyclists taking the placebo were experiencing the well-documented phenomenon of decreased immune function following intense exercise.
So, BCAAs before, during, or after your workouts could do more than just boost your muscle recovery in the short term. BCAAs may also help keep your immune system strong when you are doing tough training sessions.
6. BCAAs can be used to improve liver health
While most sports research focuses on using BCAAs for strength gains, there’s an additional branch of research that looks at using BCAAs for treating liver disease.
BCAAs interact with specific cellular signalling pathways to reverse some amounts of damage to the liver, according to a recent paper published in the journal Hepatology (6).
These new results could make BCAAs more than just a strength supplement—they may even find a use as a detox supplement, though more work needs to be done to clarify exactly who can benefit from a BCAA supplement for liver health.
BCAA side effects
BCAAs are naturally-sourced, so they’re pretty safe. Since branched chain amino acids are found in abundance in natural foods like eggs, fish, and white meat, there is very little in the way of acute side effects.
One report by Marin Manuel and C.J. Heckman raises the possibility of a link between branched chain amino acid supplementation and a neurological disease called ALS.
They noticed a link between the effects of BCAAs on neurons and the symptoms of ALS, and also noted a higher-than-expected incidence of ALS among professional soccer and football players, who report consuming BCAA supplements quite frequently.
However, the authors admit there are a huge number of confounding factors: these athletes also suffer a lot of head injuries, they’re prone to taking illegal steroids and other powerful supplements, and so on. This is an interesting hypothesis that deserves further attention, but the evidence is not nearly strong enough to caution against BCAA use.
BCAAs are safely used at very high doses for medical interventions. Branched chain amino acids are used in medical settings to treat conditions like mania and liver disease, and these doses are far higher than what’s typical for a healthy adult: research on hepatic encephalopathy has used up to 25 grams per day, and research on mania has used up to 60 grams per day (7).
Most research uses 3-6 grams per day. When it comes to dosage of branched chain amino acids for health, fitness, and muscle-building, most scientific research protocols use doses of three to six grams, taken two or three times per day.
If you want to get really technical, you can get a scale and start measuring out your BCAA dosage against your body weight—often, studies will state their dosages as “0.1g/km,” meaning 0.1 grams of BCAA per kilogram of body weight. This takes into account the fact that larger people need more of a supplement to get the same effect.
BCAA benefits FAQ
Q: Are BCAAs bad for you?
A: BCAAs are naturally found in high amounts in foods that are high in protein, like fish, poultry, and beef. So, it should not be too surprising that BCAAs are quite safe.
There are a few theoretical detrimental effects of BCAAs; some studies have suggested that a high-BCAA diet over the course of several decades could expose neurons to abnormally high amino acid levels.
However, these are extrapolations from laboratory research on individual cells, not actual observational data from humans. No strong evidence exists to indicate that BCAAs are bad for you.
Q: How do BCAAs work in your body?
A: Amino acids are the building blocks of protein in your body, and BCAAs in particular are the building blocks of muscle fibers.
So, if you want to add muscle, gain strength, or repair muscular damage, you need a steady supply of branched chain amino acids. BCAAs work by supplying your body with the ingredients it needs to synthesize new muscle and to repair damaged parts of pre-existing muscle.
Q: Are BCAA supplements necessary?
A: If you are just going to the gym to stay healthy and fit, you probably don’t need a BCAA supplement. Like the pre-workout supplements and the post-workout supplements that often incorporate BCAAs, pure BCAA supplements work best for serious athletes.
If your training regimen is very challenging, or if you are training to try to beat your one-rep max, BCAAs can start making a difference. BCAAs assist with recovery, protect your muscles from damage, and can even help keep your immune system functioning at a high level when you are in a block of tough workouts.
If you’re just doing some leisurely walking on the treadmill, or some light lifting on Nautilus-style machines, BCAAs probably are not necessary for you.
Related: Our best BCAA picks
BCAAs help you consolidate strength and muscle mass gains, and are especially useful for jump-starting your recovery after very challenging training sessions. They’re also great for concentrated post-workout recovery when you’re looking to keep your total caloric intake low.
When looking for a BCAA supplement, aim for a balance of all three branched chain amino acids for best results, and shoot for a dose of three to six grams per day, split up into several doses.