BCAAs: What Impact Do They Have on Muscle Growth, Athletic Performance, and What’s the Recommended Intake?

BCAAs: What Impact Do They Have on Muscle Growth, Athletic Performance, and What’s the Recommended Intake?

Few supplements enjoy as much popularity as BCAAs. During workouts, they are consumed by a variety of athletes, including weightlifting lovers, runners, cyclists, and other active individuals. They are most commonly taken to support muscle growth, improve recovery quality, or protect muscles during weight loss. At the same time, in recent years, we increasingly hear that taking BCAAs is completely unnecessary and that they belong in the trash instead of a shaker. Is their popularity justified, or is taking BCAAs not worthwhile at all?

In this article, you will learn about the impact of BCAAs on:

What are BCAAs?

The human body contains 20 amino acids, which are the fundamental building blocks of proteins. They serve to create and repair muscle mass and other body tissues. Moreover, our body also produces hormones and enzymes from them. Amino acids are therefore crucial for fundamental bodily processes such as digestion, nutrient absorption, and muscle growth and recovery. However, they need to be replenished regularly, as the body doesn’t store them in large numbers, unlike fats. They can be found, for example, in muscles, which may be broken down into amino acids, but that is certainly undesirable. [1]

Amino acids are divided into essential and non-essential. The main difference is that the body cannot produce essential amino acids (EAAs) on its own. These 9 amino acids (sometimes 8, as histidine can be considered semi-essential) have to be consumed through diet or nutritional supplements. To make it even more interesting, there are 3 amino acids that differ in their chemical structure, functions, and the way the body absorbs and utilizes them.

Most commonly they can be found under the abbreviation BCAA, which stands for Branched Chain Amino Acids. Specifically, these are valine, leucine, and isoleucine. These make up about 35–40% of all amino acids in the body and approximately 14% of amino acids in skeletal muscle tissue. [23]

What are BCAAs?

1. Leucine

Leucine is the most important BCAA. According to studies, it is the most effective activator of muscle protein synthesis. Body cells can recognize the level of leucine, and based on that, they send a signal to the mTOR protein complex, which can then initiate the entire muscle repair and growth process (MPS – Muscle Protein Synthesis). This is why many athletes monitor their intake of leucine through diet and supplements. For example, plant-based diets are low in leucine content, so supplementation may be necessary. [3]

2. Isoleucine

In terms of mTOR activation efficiency, isoleucine falls somewhere between valine and leucine. What it excels in is its ability to increase glucose (blood sugar) utilization and thus provide energy to muscles during athletic performance. It also has anti-catabolic effects (helps prevent muscle breakdown) that can be compared to the metabolite of leucine – HMB (β-hydroxy-β-methylbutyrate). [4]

3. Valine

The effects of valine are the least explored among these 3 amino acids. Perhaps that’s why it’s not considered as important as leucine and isoleucine. Like the other two BCAAs, it can activate the mTOR protein complex (Mammalian Target Of Rapamycin), which plays a key role in regulating muscle growth. [2]

Metabolism of BCAAs

Unlike other amino acids, BCAAs are not metabolized in the liver. This allows them to quickly enter muscle cells, where they can be almost immediately used for regeneration, growth, or as a source of energy. It is precisely their rapid usability that is one of the most valued properties of valine, leucine, and isoleucine. [5]

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7 Biggest Benefits of BCAAs

Thanks to their properties, BCAAs have something to offer to both strength and endurance athletes. How does science view their effects?

1. Muscle Growth

Larger muscles are the most common motivation for using BCAAs among bodybuilders, powerlifters, and regular gym-goers. They aim to provide the body with building material for muscle growth. Muscle mass in the body is subjected to continuous breakdown (catabolism) and formation (anabolism). If you want to grow, it’s desirable for anabolic processes to outweigh the catabolic ones. This can be best achieved through quality strength training combined with sufficient intake of amino acids from food (protein) or supplements[7]

Among all amino acids, the most effective in this regard, according to current science, is leucine. It can best activate mTOR, which triggers the process of muscle protein synthesis (MPS). However, isoleucine and valine also effectively contribute to this. Adding BCAAs or even just leucine to your post-workout protein shake can help increase the overall anabolic potential of the drink.

Is Taking BCAAs Alone Sufficient for Supporting Muscle Growth?

When building new muscle fibres, the body cannot do without all 9 essential amino acids. BCAAs alone make up only ⅓ of these building blocks. Just as when building a house, you can’t get by with just one type of material. For this reason, you should keep in mind the intake of comprehensive sources of protein (amino acids) such as meat, fish, dairy products, eggs, or whey protein. It’s also important to meet the overall daily protein intake, which for strength athletes should range from 1.4 to 2 g/kg of body weight. [6–7]

If you’re currently in the process of gaining muscle mass and want to know how to best support it through diet and training, check out some practical tips from the article 10 Nutritional and Training Tips for Maximum Muscle Growth.

What are the effects of BCAAs?

2. Maintenance of Muscle Mass

BCAAs can also be useful during dieting when you’re trying to lose fat while maintaining maximum muscle mass. With low energy intake from your diet, it’s common for the body to start burning muscle mass in addition to fat. This can be partially prevented by ensuring optimal daily protein intake and consuming BCAAs during demanding workouts. This way, the body won’t have to resort to using its own amino acid reserves in muscle tissue if needed. According to some studies, BCAAs can additionally inhibit (slow down) the degradation of muscle proteins by restricting the activity of the enzyme responsible for muscle breakdown. They also have an anti-catabolic effect. Therefore, people preparing for bodybuilding competitions, who want to maintain maximum muscle mass despite a low body fat percentage, often rely on BCAAs. [7–8]

If you’re interested in what’s important for weight loss, read our article Simple Fundamentals of Losing Weight: You’ll Be Surprised by What Really Matters.

BCAA and Maintaining Muscle Mass

3. Post-Exercise Muscle Soreness

If you engage in strength training, you’ve likely experienced that unpleasant muscle soreness, which usually occurs the day after a new or more intense workout. However, BCAAs can also help with that. Several studies have shown that their consumption during or after exercise can lead to reduced muscle soreness (DOMS – Delayed Onset Muscle Soreness). Moreover, it has been found that BCAAs can also decrease the level of creatine kinase, which is one of the indicators of muscle damage. As a result, they can help alleviate it. [9]

While the effect of BCAAs on actual recovery hasn’t been completely proven, simply reducing muscle soreness could mean that your next workout will be a bit more enjoyable.

You can read about other ways to support recovery in our article How to Support Recovery Using a Massage Gun and Other Tools?

4. Fatigue During Sports Performance

The combination of valine, leucine, and isoleucine can also help delay fatigue during training. This benefit is primarily due to the effect of BCAAs on reducing the level of the neurotransmitter serotonin. Serotonin begins to be produced in the brain during intense or prolonged exercise, leading to a sense of fatigue. However, the synthesis of serotonin requires tryptophan, which uses the same transporter as BCAAs for transfer to the brain. BCAAs can occupy most available transporters, preventing tryptophan from entering the brain.

As a result, serotonin production is reduced, and consequently, the sensation of fatigue is delayed. This allows you to train longer, harder, and extend both endurance and strength performance. [10–11]

If you’re still struggling with fatigue and don’t know why, our article Why Are You Always Tired? 7 Common Causes and Solutions might provide answers.

BCAA and Fatigue Reduction

5. Sports Performance

BCAAs are rapidly metabolized in the body and can almost immediately serve as an energy source for working muscles. They can effectively function as a supplement to an isotonic drink containing carbohydrates for maximum sports performance. When combined with the previous point regarding the reduction of fatigue, you can expect higher quality, more intense, and longer-lasting performance. Both strength athletes and endurance athletes can benefit from this. Endurance athletes can also gain from the potential positive impact of BCAAs on immunity, which can be weakened after a long training. [12–13]

BCAA and Sports Performance

6. Weight Loss and Maintaining Healthy Weight

As your meal portions decrease during weight loss, the importance of BCAA supplementation grows. During this period, it’s crucial to consume enough protein, and thus also enough amino acids, to prevent significant muscle loss. Additionally, BCAAs can serve as an energy source and protect muscle mass from being burned for energy during physical activity.

The consumption of valine, leucine, and isoleucine can also be beneficial for those who want to maintain a healthy weight. Several studies have shown that higher BCAA intake is associated with a lower incidence of overweight and obesity. [14–15]

To find out what else can make weight loss easier, read our article 10 Tips to Make Weight Loss Easier and Get in Shape.

7. Other Potential Effects of BCAAs

BCAAs are not only studied in relation to sports performance and weight. There are studies that mention their beneficial effects on liver function, especially in people with cirrhosis or other liver conditions. These amino acids are also used in clinical practice, especially after surgeries, when people have weakened immunity and are more susceptible to significant muscle loss. However, even in this case it’s crucial to have sufficient intake of all essential amino acids. [16–18]

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Sources of BCAAs

BCAAs are not something exceptional; you commonly consume them through normal foods such as meat, eggs, and dairy products. For instance, high-quality whey protein is a natural source of BCAAs. As concentrated supplements, they are most commonly found in the form of soluble powder, tablets, or drinks. [19–20]

Average BCAA Content in Foods and Supplements

Food (100 g)

Total BCAA Content (g)

Whey Protein19.8
Pea Protein17.9
Beef4.47
Chicken5.51
Canned Tuna4.56
Egg2.53
Greek Yogurt1.7

Recommended BCAA Intake

  • It’s generally recommended to consume a total of 20 g of BCAAs per day. [21]
  • Of which 2–10 g leucine.
  • Ideal isoleucine intake is around 48–72 mg/kg of body weight.
  • Optimal intake for valine is not yet determined.
  • Typically, meeting the overall daily BCAA intake (from food and supplements) is sufficient, and you’ll most likely also meet the recommended values for leucine, isoleucine, and valine.
  • In a single supplement serving, you should take 5–10 g of BCAAs.
  • Taking BCAAs is ideal before or during exercise for energy replenishment and muscle protection, or after exercise as part of your recovery drink.
  • They can also be taken throughout the day to increase the overall daily intake of these essential amino acids.
Dosing of BCAAs

How to Take BCAAs?

BCAAs can be taken in several forms:

  • Soluble Powder: All you need to do is to dissolve it in some water. It’s often flavoured, as pure BCAAs have a bitter taste. This form is suitable for consumption during training or as a way to diversify your fluid intake throughout the day.
  • Tablets: Take them before or after training, or anytime during the day. Always take them with a sufficient amount of water.
  • Ready-to-Drink (RTD) Drinks: These canned drinks often contain caffeine, selected vitamins, or minerals. They’re ideal before workouts when you need an energy boost. There are also caffeine-free options that can be consumed even in the evening.
  • Complex Amino Acid Products: BCAAs can also be supplemented through more comprehensive products containing all 9 essential amino acids.

BCAA Ratios in Supplements

If you’ve previously taken BCAAs, you might have noticed that the package indicated a ratio, such as 4:1:1 or 2:1:1. However, you might also encounter values like 10:1:1 or even 20:1:1.

This ratio indicates the proportions of individual BCAAs present in the supplement – leucine : isoleucine : valine. Considering that leucine has the most significant anabolic effect, it makes sense for it to predominate in the product.

  • Currently, the 2:1:1 ratio is considered ideal, which, according to studies, is the most comprehensive in terms of supporting muscle growth, providing energy, and reducing fatigue. [22]
  • However, even ratios like 3:1:1 or 4:1:1 won’t steer you in the wrong direction if your primary goal is maximizing muscle growth.
  • A higher leucine content, like 20:1:1, doesn’t offer any added value according to current studies and might not be as effective as, for instance, 2:1:1.
BCAAs Use

Who Should Use BCAAs?

  • BCAA supplementation makes the most sense for people who don’t get enough of them through their diet. This includes vegetarians, vegans, and others who restrict or eliminate BCAA-rich animal products. Supplements can help them increase the quality of amino acids in their diet.
  • Similarly, they can be very useful for performance athletes such as bodybuilders, fitness competitors, endurance runners, cyclists, and other active individuals who naturally have higher requirements for essential amino acids necessary for muscle recovery.
  • Moreover, those on a diet who are exercising intensively and want to maintain maximum muscle mass can also benefit from supplementing BCAAs.

If you’ve completely excluded animal products from your diet and are curious about which nutrients you might be lacking, you can learn about them in the article Which Nutrients Are Most Commonly Missing in a Vegan Diet and How to Supplement Them?

Side Effects of BCAAs

Valine, leucine, and isoleucine are amino acids found in common foods and are also part of the human body. These are completely natural substances that the body knows and that can be easily metabolized. At regular dosage, they do not cause adverse effects in healthy individuals. [24]

What should you remember?

BCAAs certainly can’t be considered a miraculous supplement that will multiply your results overnight. However, they definitely don’t belong to the bin. They can help you achieve better results in gaining muscle mass, train harder, delay fatigue during exercise, or reduce soreness in strained muscles. During weight loss, they can contribute to protecting muscle mass from being burned for energy. If these are your goals, food sources rich in these amino acids or BCAA supplements should definitely be a part of your daily diet.

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Sources:

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[7] Morse, T. Efficacy of BCAA supplementation for exercise performance and recovery: A narrative review.

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[9] The effect of branched-chain amino acid on muscle damage markers and performance following strenuous exercise: A systematic review and meta-analysis. – https://cdnsciencepub.com/doi/10.1139/apnm-2021-0110?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed

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[11] Gervasi, M., Sisti, D., Amatori, S., Donati Zeppa, S., Annibalini, G., Piccoli, G., Vallorani, L., Benelli, P., Rocchi, M. B. L., Barbieri, E., Calavalle, A. R., Agostini, D., Fimognari, C., Stocchi, V., & Sestili, P. Effects of a commercially available branched-chain amino acid-alanine-carbohydrate-based sports supplement on perceived exertion and performance in high intensity endurance cycling tests. – https://doi.org/10.1186/s12970-020-0337-0

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[13] Negro, M., Giardina, S., Marzani, B., & Marzatico, F. Branched-chain amino acid supplementation does not enhance athletic performance but affects muscle recovery and the immune system.

[14] Qin, L.-Q., Xun, P., Bujnowski, D., Daviglus, M. L., Van Horn, L., Stamler, J., He, K., & INTERMAP Cooperative Research Group. Higher branched-chain amino acid intake is associated with a lower prevalence of being overweight or obese in middle-aged East Asian and Western adults. – https://doi.org/10.3945/jn.110.128520

[15] Li, Y.-C., Li, Y., Liu, L.-Y., Chen, Y., Zi, T.-Q., Du, S.-S., Jiang, Y.-S., Feng, R.-N., & Sun, C.-H. The Ratio of Dietary Branched-Chain Amino Acids is Associated with a Lower Prevalence of Obesity in Young Northern Chinese Adults: An Internet-Based Cross-Sectional Study. – https://doi.org/10.3390/nu7115486

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[24] HOLEČEK, M. Side Effects of Amino Acid Supplements. – https://doi.org/10.33549/physiolres.934790

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