BCAA Benefits: A Review of Branched-Chain Amino Acids

Branched-chain amino acids (BCAAs) are a group of three essential amino acids:

BCAA supplements are commonly taken to boost muscle growth and enhance exercise performance. They may also help with weight loss and reducing fatigue after exercise.

This article contains all the most important information about branched-chain amino acids and their benefits.

BCAAs consist of three essential amino acids:

These amino acids are grouped together because they are the only three amino acids to have a chain that branches off to one side.

Like all amino acids, BCAAs are building blocks your body uses to make proteins.

BCAAs are considered essential because, unlike nonessential amino acids, your body cannot make them. Therefore, it is essential to get them from your diet.

Summary

The three BCAAs are leucine, isoleucine, and valine. All have a branched molecular structure and are considered essential to the human body.

BCAAs make up a large chunk of the body’s total amino acid pool.

Together, they represent around 35–40% of all essential amino acids present in your body and 14–18% of those found in your muscles (1).

Contrary to most other amino acids, BCAAs are mostly broken down in the muscle, rather than in the liver. Because of this, they are thought to play a role in energy production during exercise ( 2 ).

BCAAs play several other roles in your body.

First, your body can use them as building blocks for protein and muscle (3, 4, 5 ).

They may also be involved in regulating your blood sugar levels by preserving liver and muscle sugar stores and stimulating your cells to take in sugar from your bloodstream ( 6 , 7 , 8 , 9 ).

What’s more, BCAAs may help reduce the fatigue you feel during exercise by reducing the production of serotonin in your brain ( 10 ).

Out of the three, leucine is thought have the biggest impact on your body’s capacity to build muscle proteins ( 3 , 11 ).

Meanwhile, isoleucine and valine seem more effective at producing energy and regulating your blood sugar levels ( 6 , 12 ).

Summary

Your body can use BCAAs to build muscle protein and produce energy. They may also have an effect on your brain that reduces fatigue.

Consuming BCAAs may help reduce physical and mental fatigue.

A study reports that consuming 20 grams of BCAA dissolved in 400 mL of water and 200 mL of strawberry juice 1 hour before working out increases time to exhaustion in participants ( 13 ).

In another study, it was found that participants reported up to 15% less fatigue in those given BCAAs during exercise, compared with those who were given a placebo ( 14 , 15 ).

In one study, this increased resistance to fatigue helped the BCAA group exercise for 17% longer before reaching exhaustion compared with the placebo group ( 12 ).

However, not all studies found that decreased fatigue caused improvements in physical performance ( 14 , 16 , 17).

Summary

In some people, BCAAs may help reduce exercise fatigue. Whether this improves exercise performance is still up for debate.

BCAAs may also help your muscles feel less sore after exercise.

One way they may do so is by lowering blood levels of the enzymes creatine kinase and lactate dehydrogenase, which are involved in muscle damage. This may improve recovery and provide some protection against muscle damage ( 18 ).

Various studies asked participants to rate their muscle soreness levels after performing certain strength-training exercises.

Participants who were given BCAA supplements rated their muscle soreness levels as much as 33% lower than those given a placebo ( 19 , 20 , 21 ).

In some cases, those given BCAAs also performed up to 20% better when they repeated the same strength-training tests 24–48 hours later ( 22 , 23 ).

However, effects may vary based on your gender or the total protein content of your diet ( 19 , 24).

Summary

BCAAs taken before or after strength training may reduce muscle soreness following your workout. However, the effects may vary from one person to another.

Some people who purchase BCAA supplements do so to increase their muscle mass.

After all, research shows that BCAAs do activate enzymes responsible for building muscle ( 25 ).

Some studies also show that BCAA supplements may be effective at increasing muscle mass, especially if they contain a higher proportion of leucine than isoleucine and valine ( 25 , 26 ).

However, there’s currently no evidence that getting your BCAAs from a supplement is any more beneficial than getting them from your diet or from a whey or soy protein supplement.

In fact, studies show that taking supplements with whole protein may, at least in some cases, be better for muscle growth than taking supplements with individual amino acids ( 27 ).

Summary

Getting enough BCAAs may boost muscle growth. You can get them from high protein foods in your diet or through supplements.

BCAAs may also help maintain normal blood sugar levels.

Leucine and isoleucine are thought to increase insulin secretion and cause your muscles to take in more sugar from your blood, thereby decreasing your blood sugar levels ( 28 , 29 ).

However, in practice, not all studies back up these effects ( 30 , 31 ).

In fact, some even report potential rises in blood sugar levels, depending on the type of diet participants followed. For instance, when BCAAs are combined with a high fat diet, consuming them in supplement form may lead to insulin resistance ( 32 , 33 ).

That said, many of these studies were done on animals or cells, which means that their results may not be totally applicable to humans.

In humans, effects also seem to vary between participants.

For example, in one recent study participants with liver disease were given 12.5 grams of BCAAs three times per day. In 10 participants, blood sugar levels were reduced, while 17 participants experienced no effects ( 34 ).

More studies are needed before strong conclusions can be drawn.

Summary

BCAAs may help promote blood sugar management, at least in some cases. However, more studies are needed to confirm their effects.

Branched-chain amino acids may help prevent weight gain and enhance fat loss.

In fact, observational studies report that those consuming an average of 15 grams of BCAAs from their diet each day may have up to 30% lower risk of becoming overweight or having obesity than those consuming an average of 12 grams per day ( 35 , 36 ).

However, it’s worth noting that those consuming fewer BCAAs also consumed around 20 fewer grams of total protein per day, which may have influenced results.

If you’re attempting to lose weight, BCAAs may help your body get rid of unwanted fat more effectively.

Competitive wrestlers consuming a high protein, calorie-restricted diet supplemented with BCAAs lost 3.5 more pounds (1.6 kg) than those given a soy protein supplement over a 19-day study period ( 37 ).

The BCAA group also lost 0.6% more body fat than the soy protein group, despite consuming equivalent calories and slightly less total protein each day ( 37 ).

In another study, weightlifters given 14 grams of BCAAs per day lost 1% more body fat over an eight-week study period than those given 28 grams of whey protein per day. The BCAA group also gained 4.4 pounds (2 kg) more muscle ( 38 ).

That said, these two studies have some flaws. For instance, they provide little information about the composition of the supplement and of the diet followed, which could have influenced the outcomes.

What’s more, studies examining the effects of BCAAs on weight loss show inconsistent results ( 39 ).

Summary

BCAAs may help prevent weight gain and enhance weight loss. However, more research is needed to determine whether supplements provide any added benefits over a high protein diet.

BCAAs may help reduce complications linked to liver failure.

One possible complication is hepatic encephalopathy (HE), which can lead to confusion, loss of consciousness and coma.

A 2014 review suggests that in patients with liver disease, BCAA supplements may be more beneficial than other supplements at reducing the severity of HE ( 40 ).

However, BCAAs did not improve overall survival rate, and they didn’t lower the risk of other complications, such as infections and gastric bleeding ( 40 ).

Another review of studies in patients undergoing liver surgery reported that BCAA-enriched solutions may help improve liver function, reduce the risk of complications, and decrease the duration of hospital stay ( 41 ).

BCAA supplements may also be effective at reducing fatigue and improving weakness, sleep quality, and muscle cramps in individuals with liver disease ( 42 ).

In cases of liver cancer, taking BCAA supplements may help reduce water retention and decrease the risk of premature death ( 43 ).

However, if you have liver disease, please speak with your healthcare team about using BCAA supplements before starting them.

Summary

BCAA supplements may be effective at improving liver function and decreasing the risk of complications in individuals who have liver disease.

If you’d like to start supplementing with branched-chain amino acids, you should speak with a healthcare professional to decide if it’s right for you and how much you should take.

Furthermore, there are no official recommended daily requirements for BCAA though there are studies that have suggested different amounts ( 44 , 45 ).

However, people who include sufficient protein-rich foods in their diets most likely do not need to take supplements.

The best time to take BCAA supplements is before and/or after your workout. Many people who are trying to gain muscle also take them in the morning and before bed.

However, whether the exact timing makes a big difference for this has not been studied properly. But you should follow the manufacturer’s instructions and do not exceed the maximum listed dosage.

Summary

There is no official recommended dose for BCAAs, and since a diet that is sufficient in protein-rich foods may be all you need, you should speak with a healthcare professional before supplementing.

BCAAs (Branched-Chain Amino Acids): Are There Health Benefits?

Branched-chain amino acids (BCAAs) play an important role in the building and repairing of muscles. They get their name from their chemical structure, which also affects the way the body uses them. The three BCAAs are leucine, valine, and isoleucine. They comprise three of the nine essential amino acids, considered essential because the body cannot make them but must get them from food.

Most amino acids are metabolized or broken down in the liver. BCAAs are mostly metabolized in muscle tissue. That makes BCAA supplements attractive to athletes and bodybuilders, but research doesn’t offer strong evidence for the use of BCAAs to increase muscle mass. BCAA supplements may be no better for muscle growth and recovery than BCAAs from dietary sources.

An inability to metabolize BCAAs causes several serious conditions. Treatment sometimes involves reducing protein intake.

Health Benefits

Since scientists discovered branched-chain amino acids in the mid-1800s, they have studied them intensively. They know that BCAAs are important for many body functions, but there is much more for science to investigate.

Some research supports these health benefits of BCAAs:

Muscle Building

Several studies suggest that BCAAs supplements may increase muscle mass and strength during training. The studies were short term and did not show that supplementing with BCAAs is superior to getting them from dietary sources.

Muscle Recovery

Some studies suggest that BCAAs may ease soreness and help with recovery following exercise. The effect may not be significant enough to warrant the use of supplements.

People with cirrhosis of the liver often have low levels of BCAAs, and supplementation may help. Adding BCAAs does not always improve symptoms, however, and those with cirrhosis should use BCAAs only under a doctor’s supervision.

Those who take certain drugs may have a condition called tardive dyskinesia that causes uncontrolled movements. Some antipsychotic drugs and some anti-nausea drugs can cause this condition. Some evidence indicates that supplements of BCAAs can reduce symptoms.

Health Risks

Branched-chain amino acid supplements are considered safe when taken in proper doses for short periods of time. As far as researchers have observed, BCAAs cause very few adverse effects. BCAAs may interact with medications, including thyroid hormones, drugs for Parkinson’s, and medicines for diabetes.

High Blood Pressure

One study has found that high concentrations of BCAAs are associated with an increased risk of high blood pressure in middle-aged men and women. This study had some limitations, so the topic needs further study.

Before Surgery

Research indicates that limiting amino acids before surgery could reduce the risk of complications. In particular, the risk of stroke and heart attack may be lessened.

Amounts and Dosage

A typical BCAA dosage for muscle enhancement is up to 20 grams a day taken in divided doses. This amount appears to be safe. If you are taking BCAAs for a purpose other than muscle growth, your doctor will specify the dosage.

You can get BCAAS from animal proteins such as meat, fish, eggs, milk, and poultry. You can also get them from plant-based foods when combined to offer all the essential amino acids. The body uses BCAAs found in food efficiently.