The Key Benefits of BCAA Supplementation for Athletes

UK Fitness Pro
UK Fitness Pro
· 12 min read
An image representing the benefits of BCAAs for athletes

Amino acids are often referred to as the "building blocks of protein", as proteins are basically complex arrangements of amino acids. 

Muscle tissue accounts for about 40% of the weight of a typical human body, and about 20% of this tissue is comprised of muscle protein. Therefore, a 100-kg individual contains about 8 kilograms of muscle protein (comprised of amino acids). Branched-chain amino acids (BCAAs; leucine, isoleucine, valine) are “essential” amino acids. This simply means the body is unable to synthesise them in sufficient quantities, and so they need to be consumed. 

Since BCAAs constitute 35% of the essential amino acids in muscle proteins (1), it’s perhaps unsurprising that amino acid supplements like BCAAs have been consistently linked to increased athletic performance. 

Cycling and the Benefits of BCAA Supplementation

In a study published in Amino Acids (2), researchers asked trained cyclists to consume either a BCAA supplement or a placebo, taken for 10 weeks at 12 grams per day. Before and after the 10-week period, the participants completed the Wingate test, an assessment of anaerobic power where the individual pedals as hard as they can for 30 seconds on a cycle erg. While no substantial improvements were seen in the placebo group, the BCAA group exhibited a 4% increase in mean power and a massive 20% increase in peak power                                   

Running and the Benefits of BCAA Supplementation

An image representing the benefits of BCAAs for runners

BCAAs seem to also benefit runners. Researchers in Taiwan (3) observed that national-level endurance runners ran significantly faster over 5,000 metres if, an hour before running, they consumed BCAAs (mean time: 17 minutes, 45 seconds) compared to a placebo (mean time: 18 minutes, 20 seconds). Likewise, they were significantly faster over 10,000 metres after BCAA supplementation (mean time: 34 minutes, 52 seconds) compared to placebo (mean time: 36 minutes, 15 seconds).                                        

Swimming and the Benefits of BCAA Supplementation

As well as endurance, BCAAs have been linked to improved performance when undertaking high-intensity interval training (HIIT). 

An article published in Nutrients (4) describes the effects of BCAAs on lap times among national- and international-level young swimmers. When the participants took BCAAs an hour before eight 50-metre sprints (with 3-minute rests in between), they were significantly faster than when they took a placebo. On average, laps completed after BCAA consumption were almost half a second faster. 

This might not seem like much, but in the 50-metre freestyle finals at the Rio Olympics, only a hundredth of a second separated silver from gold.                            

Tennis and the Benefits of BCAA Supplementation

BCAAs can also minimise the cognitive decline associated with fatigue. 

Researchers in Taiwan (5) assessed the effects of BCAAs on perceptual–motor skills among national-level tennis players. In tennis, these skills refer to “the ability to acquire information about the opponent’s body and racquet movements, then select and execute appropriate actions”. To measure this ability, the researchers had the player stand at one end of the court and placed an examiner and a serving machine at the other. Once a ball was served, the examiner randomly walked to one side of the court, and the player had to return the ball to the opposite side. When well rested, players managed this with near-perfect accuracy, regardless of whether they had taken BCAAs or a placebo. 

However, when tested again after two hours of match play, the accuracy of players who had taken the placebo plummeted (69%), while the accuracy of those who had taken BCAAs remained almost flawless (94%). 

Football and the Benefits of BCAA Supplementation

Additionally, BCAAs can benefit perceptual–motor skills among football players. 

An image representing the benefits of BCAAs for football players

An article in Applied Physiology, Nutrition, and Metabolism (6) describes how researchers had professional football players run for 90 minutes on a treadmill and respond, using hand-held buttons, to various stimuli presented at intervals throughout; if they saw a red light, they pressed the right button; if they heard a sound, they pressed the left; and if they saw a green or yellow light, they pressed neither. Compared to when they took a placebo, the players reacted to the stimuli 10% faster if they took a 7-gram BCAA supplement an hour before the test, suggesting BCAAs might help footballers respond more effectively to events when involved in real matches. 

This may be because BCAAs can reduce serotonin (a marker of central fatigue) in the brain (7). 

Strength Training and the Benefits of BCAA Supplementation

As well as endurance athletes, some of the latest research on BCAA supplements has looked at the benefits for those whose main focus is resistance training, including whether BCAA intake can promote recovery following muscle damage.   

For instance, in one placebo-controlled study, researchers from the UK and Australia (8) investigated the benefits of BCAAs for muscle recovery in resistance-trained athletes. Participants were given a BCAA dosage of 0.087 g/kg body mass, with a 2:1:1 ratio of leucine, isoleucine, and valine. The study involved a muscle-damaging exercise protocol consisting of 6 sets of 10 full squats at 70% of their 1RM. The research showed that acute BCAA supplementation led to an enhanced recovery in muscle strength, counter-movement jump (CMJ) height, and perceived delayed onset muscle soreness (aka DOMS) compared to a placebo group. These effects were particularly noticeable at 24 and 48 hours post-exercise, highlighting the efficacy of BCAAs in accelerating recovery post-strength training.

Consistent with this, a systematic review and meta-analysis published in Sports Sciences for Health (9) suggests that taking BCAA powder is associated with lower levels of post-exercise creatine kinase, which is a marker of skeletal muscle breakdown and damage. 

Bodybuilding and the Benefits of BCAA Supplementation

In a study published in the Journal of the International Society of Sports Nutrition (10) revealed significant benefits of BCAA supplementation for 36 strength-trained males focused on modifying their body composition (e.g., increasing their lean body mass). 

An image representing the benefits of BCAAs for bodybuilders

Participants, divided into three groups, received either 14 grams of BCAAs, 28 grams of a protein supplement (whey protein), or 28 grams of carbohydrates from a sports drink. Alongside a resistance-training programme, the BCAA group exhibited a notable increase in lean mass and strength gains. Specifically, they showed greater muscle growth and muscle mass improvement compared to other groups. BCAA supplementation led to more pronounced gains in body weight and lean mass and a reduction in body fat percentage. 

Additionally, strength improvements were significant in both the bench press and squat exercises, underscoring the effectiveness of BCAAs in enhancing muscle repair and building during bodybuilding activities.

The Benefits of BCAA Supplementation for Non-Athletes

While most of the studies referred to above have looked at how BCAAs can play an important role in the performance of competitive athletes, there's also considerable evidence that BCAA supplementation can help normal, healthy adults get the most out of their training sessions. 

BCAA's influence on fatigue

Research led by scientists at the University of Nebraska (11) has investigated the effects of essential amino acid (EAA) supplementation, including BCAAs, on untrained women. The sample consisted of 21 participants, randomly assigned to either a placebo group or an EAA supplementation group. Over six weeks, alongside aerobic and heavy-resistance exercise, the EAA group received an average daily dose of 18.3 grams of EAAs in pill form. The EAA group exhibited a significant improvement in treadmill time to exhaustion, suggesting enhanced aerobic muscular endurance. 

BCAAs and muscle damage: 

One study published in the International Journal of Sport Nutrition and Exercise Metabolism (12) focused on the effects of BCAA supplementation on markers of muscle damage following endurance exercise. Nine untrained men participated, performing three 90-minute cycling sessions while consuming a BCAA supplement, a carbohydrate drink, or a placebo. The study measured creatine kinase (CK) and lactate dehydrogenase (LDH) levels (markers of muscle damage). The results indicated that there was a significant difference between the BCAA group and the other groups with regard to CK and LDH levels at various post-exercise intervals (i.e., CK and LDH levels were lower in the BCAA group), suggesting that they can mitigate muscle damage and aid recovery after endurance exercise.

An image representing the benefits of BCAAs for non-athletes

Effects on perceived exhaustion: 

The same researchers (13) also examined the effects of BCAA supplementation on perceived exertion in untrained males. The study included nine participants who underwent three 90-minute cycling sessions supplemented with either BCAAs, a carbohydrate drink, or a placebo. The results showed that  BCAA supplementation led to a reduction in perceived exertion at specific time points during the exercise. 

BCAAs as an energy source: 

One study published in the Journal of Science and Medicine in Sport (14) explored the effects of BCAA supplementation on cycling performance in recreationally active men. The research involved eighteen participants who underwent a cycling time trial, consuming either BCAAs or a placebo. The findings indicated that BCAA supplementation led to a significant reduction in time-to-completion and perceived exertion. The improved performances in the BCAA group may reflect the body using BCAAs as a fuel source during exercise

BCAAs and muscle soreness: 

Researchers in Japan (15) have examined the effects of BCAA supplementation on muscle soreness and recovery. The research involved 12 untrained women who ingested either BCAAs or a placebo before performing squat exercises. The study focused on delayed-onset muscle soreness (DOMS), muscle force during contractions, and various blood markers. Results showed that BCAA supplementation led to significantly lower muscle soreness and less reduction in muscle force compared to the placebo. Additionally, BCAAs appeared to prevent the increase in blood markers of muscle damage typically observed after exercise. This suggests that BCAAs can reduce exercise-induced muscle damage and soreness, enhancing recovery.

Each of these studies contributes to understanding how BCAA supplementation can be beneficial beyond the realm of athletic performance, offering advantages in areas like muscle maintenance, energy production, immune function, and overall health.

Integrating BCAA Supplements into a Well-Rounded Diet

To maximise the benefits of BCAA supplementation for enhanced physical fitness and shorter recovery times, it's essential to incorporate them thoughtfully into a well-rounded diet comprised of real food. Here's how to do it:

Timing is Key: While there's no "right time" to take BCAAs, the best results are generally seen when they're consumed around your workout times. Taking BCAAs before or immediately after workouts can help fuel your muscles and minimise muscle protein breakdown. 

Combine with Protein-Rich Foods: While BCAAs are crucial, they should be part of a diet that includes complete protein sources like dairy products (e.g., cottage cheese), meat, and plant-based proteins. By getting enough protein through dietary sources, you can ensure that you have the type of balanced intake of amino acids required for effective muscle building. If you're struggling to meet your recommended level of protein intake, there are a wide range of protein supplements (e.g., wheypeasoyrice, and hemp protein powders). 

An image representing the integration of BCAAs into a balanced diet

Mind Your Dosage: Typically, 5-10 grams of BCAAs per serving are sufficient for anabolic effects. However, it's important to align your BCAA intake with your physical activity level and dietary protein sources to avoid unnecessary supplementation. For example, as whey protein powder contains BCAAs, there may be negligible effects on your rate of muscle protein synthesis associated with taking BCAAs at the same time as whey protein compared to just using whey protein. 

For Weight Management: If you're aiming for weight loss, BCAAs can help maintain muscle mass while you're on a calorie deficit. Include them as part of a diet that's rich in whole foods and balanced macronutrients.

Monitor Your Overall Health: Especially for those with medical conditions, it's crucial to consider how BCAAs fit into your overall dietary plan. There's evidence that BCAAs may be beneficial for certain conditions (e.g., liver disease including liver cirrhosis and muscle wasting conditions), though they could increase the symptoms of others (e.g., amyotrophic lateral sclerosis). Additionally, there's evidence that BCAA supplementation can entail positive significant changes in immune system functioning following intense exercise (16)

In summary, BCAAs should complement a diet that's already rich in diverse protein sources. By strategically using these supplements, you can support muscle protein synthesis, reduce recovery time, and maintain a high level of physical fitness.


The benefits of BCAA supplementation include increased anaerobic power, endurance, and perceptual–motor skills. 

Some of these benefits might be due to BCAAs activating enzymes that are key to muscle synthesis (17), while others could result from BCAAs minimising exercised-induced increases in serotonin in the brain, which are associated with fatigue (18). Whatever the precise mechanisms, it’s clear that BCAA supplementation can benefit a range of athletes in a number of ways. 

So, if you’re looking to improve your fitness level, reduce muscle fatigue, and get the most out of your workouts (while also adding a little flavour to your water), why not give BCAAs a try? 

If you liked this article, you might also be interested in this one on how creatine can benefit different types of athletes or this one on how the strongest men in the world use supplements like BCAAs. You might also like our articles on how BCAAs compare to EAAs, beta-alanine, whey protein powdercreatinepre-workout, and different amino acids (e.g., glutamine; reflecting the importance of this amino acid, it's often incorporated into other amino acid supplements, as in the case of G BCAAs and G leucine). We also have an article that compares BCAAs in powder form vs. pill form

About the Author

Dave Robinson, a co-founder of, has a background in psychology (BSc) and neuroscience (MSc, PhD). As well as strength training, he enjoys endurance challenges and has run ultramarathons, cycled across several countries, and completed the Three Peaks Challenge. When writing, he draws on scientific evidence to understand the pros and cons of different diets, supplements, and training regimes. 


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