BCAAs (branched-chain amino acids): What You Need to Know

Woman weight lifter

There are thousands of different supplements available for your consumption – all of which promise the world (many of which, unfortunately, fail to deliver on that promise).

One supplement that has become a mainstay in the realm of health and fitness are Branched Chain Amino Acids (or BCAAs for short) – but are they all they are cracked up to be?

Here is what you need to know.

What are BCAAs?

man deadlifting

As I alluded to above, BCAA stands for ‘branched chain amino acid’ – which describes a specific type of ‘amino acid’.

An amino acid a type of compound that your body uses make proteins. They are ultimately the building blocks of all your cells, in which they are used to make pretty much everything in your body that has a physical structure.

Now, some of these amino acids are considered non-essential because they can be made within your body, while others are considered essential because they cannot be made in your body – and therefore must be obtained through diet.

BCAAs fall into the essential amino acid category.

There are three specific BCAAs – leucine, isoleucine, and valine.

Despite there only being three of them, BCAAs make up approximate 35% of all the muscle protein found in your body. As such, they also stimulate protein production in your muscle tissue, which is why they are commonly used by fitness enthusiasts to aid muscle growth and recovery.

What are the benefits of BCAAs?

As I alluded to above, they are commonly used to accelerate muscle growth aid recovery – but is this their only real benefit? And how effective are they?

Well, interestingly, there is evidence to suggest that BCAAs can be used to help several different aspects of health and fitness.

BCAA and weight loss

One of the supposed benefits of BCAAs is their ability to help promote weight loss – however this suggestion is not entirely accurate.

Consuming BCAAs increase muscle protein synthesis (which is the process your body uses to build new muscle tissue). While this does not have a direct impact on weight loss, it does have a benefit if your primary goal is to lose weight.

When people lose weight, they also lose muscle mass in the process. This is often considered to be unavoidable aspect weight loss, which simply comes with being in a calorie deficit.

Over time, this loss of muscle mass can cause a small reduction in your metabolism, which can make keeping the weight you have lost off harder.

However, supplementing with BCAAs appears to attenuate the loss of muscle mass that normally occurs during a weight loss phase – which can in turn, make maintaining a leaner physique easier.

Interestingly, this will also allow you to lose more weight over the duration of weight loss phase (Mourier, 1997).

BCAA and muscle gain

Weight lifting

Because of their ability to increase muscle protein synthesis, there is evidence to suggest that the supplementation of BCAAs will also increase muscle growth when combined with a progressive resistance training routine (Stoppani, 2009).

Interestingly, this benefit seems to be enhanced if someone is consuming a diet that is slightly lower in protein (like a vegetarian or vegan diet), or if they are in a calorie restricted state.

So yes, there is good reason as to why BCAAs are so popular in bodybuilding circles.

BCAA and recovery 

We have already established that BCAAs work by stimulating the production of muscle protein and preventing their breakdown – which has been shown to help promote muscle growth and aid muscle preservation during weight loss.

But what about recovery?

Well, the good news is there is a large body of evidence suggesting that supplementing with BCAAs around your workout will aid in post-exercise recovery. This often means less muscle soreness after training, combined with better exercise performance during subsequent training sessions (Osmond, 2019).

There is reason to believe that over time this will allow you to train at higher intensities across a long duration, which may increase your long-term progress.

Related Article: Does Protein Impact Trained Athletes Differently?

BCAA and brain health 

In the brain, BCAAs contribute to the production of two incredibly important neurotransmitters – being the excitatory glutamate and inhibitory gamma-aminobutyric acid (or GABA, for short).

Because of this interaction, they have been hypothesized to promote efficient brain health, improve cognitive function, and even repair brain tissue.

However, while this makes sense from a mechanistic perspective, there is very little research in the area.

In fact, in humans, the only real research has been conducted in people with liver disease who have also developed brain damage. In this populations, the supplementation of BCAAs has been shown help reverse brain damage and improve brain tissue health (Gluud, 2015).

While this does suggest the supplementing BCCAs may improve brain function, we need more research in the area before we can make a truly definitive decision.

BCAA and regulation blood sugar

Finally, BCAAs also appear to increase blood sugar uptake and promote its storage in the muscle tissue. In this manner, it has also been shown to reduce the breakdown of muscle carbohydrates, preserving it for use later (Doi, 2007).

While this may help improve exercise performance, its impact on health remains somewhat unclear.

There is recent evidence demonstrating that if people with Type II diabetes (and subsequently higher than normal blood glucose levels) reduce their dietary intake of BCAAs, they see an improvement in blood sugar control (Karusheva, 2019).

Although this does not suggest that BCAAs will cause type II diabetes, it does indicate that people with the disease may be best to avoid them until we have more research in the area.

Who should take BCAAs?

Well, in short, if you want to improve recovery, optimize athletic performance, enhance muscle growth, and promote more effective weight loss, then BCAAs are for you.

Additionally, as I alluded to above, their supplementation seems to become more effective in those individuals who don’t get a huge amount of BCAAs through their natural diet – and given that they are found in meat based products, this typically means those who follow a vegetarian or vegan way of eating.

If you do follow a plant-based diet, then BCAA supplementation may be a very useful strategy to optimize your health and performance.

When is the best time to take BCAAs?


Now onto one of the most common questions that come up when discussing this supplement – when to take BCAAs?

Research has shown that their effectiveness seems to increase if you take them both before and after exercise (~30-60 minutes before and after). This means that you will have adequate BCAAs available during and after your session to enhance recovery.

In terms of BCAA dosage recommendations, the literature suggests an intake of around 91mg per pound of bodyweight.

With this in mind, if you weighed 165 pounds, you would need to take about 15 grams of BCAAs around your workout for maximum effectiveness. This would be split into a serving of 7.5 grams before and after your training session.

Finally, it is important to note that while dosages of up to 35 grams per day have bene shown to be safe and tolerable, consuming too many BCAAs can have some negative effects.

BCAA side effects include:

  • Stomach discomfort
  • Impaired exercise performance
  • Worsened recovery after exercise

As such, sticking to the recommended dosing is integral to enhancing your results.

Related Article: How Much Protein Should You Eat?

Take Home Message

BCAAs are worth the hype.

With evidence to suggest that they improve recovery, promote muscle growth, and help during weight loss, it is highly likely they will be a useful addition to your supplement regime – especially if you eat a low-protein or plant based diet.


Mourier, A., et al. “Combined effects of caloric restriction and branched-chain amino acid supplementation on body composition and exercise performance in elite wrestlers.” International journal of sports medicine 18.01 (1997): 47-55.

Stoppani, Jim, et al. “Consuming a supplement containing branched-chain amino acids during a resistance-training program increases lean mass, muscle strength and fat loss.” Journal of the International Society of Sports Nutrition 6.1 (2009): 1-2.

Osmond, Adam D., et al. “The Effects of Leucine-Enriched Branched-Chain Amino Acid Supplementation on Recovery After High-Intensity Resistance Exercise.” International journal of sports physiology and performance 14.8 (2019): 1081-1088.

Gluud, Lise Lotte, et al. “Branched‐chain amino acids for people with hepatic encephalopathy.” Cochrane Database of Systematic Reviews 9 (2015).

Doi, Masako, et al. “Hypoglycemic effect of isoleucine involves increased muscle glucose uptake and whole body glucose oxidation and decreased hepatic gluconeogenesis.” American journal of physiology-endocrinology and metabolism 292.6 (2007): E1683-E1693.

Karusheva, Yanislava, et al. “Short-term dietary reduction of branched-chain amino acids reduces meal-induced insulin secretion and modifies microbiome composition in type 2 diabetes: A randomized controlled crossover trial.” The American journal of clinical nutrition 110.5 (2019): 1098-1107.

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