BCAA vs Beta-Alanine Supplements: Which Should You Take?

UK Fitness Pro
UK Fitness Pro
· 12 min read
Beta-alanine and BCAA supplements

As someone who lifts most days, I've been taking branched-chain amino acids (BCAAs) for years. 

Since there's loads of evidence that they improve body composition, strength, endurance, and recovery, you can get them on Myprotein for a tenner, and they make water taste good, it's almost a no-brainer. On the other hand, I've only used beta-alanine during very long runs as it's best known for enhancing endurance. However, I'm planning to do some long runs this year (up to 100 km), so I wanted to learn more about beta-alanine and revisit studies on BCCAs and athletic performance. With a background in biological science (BSc, MSc, PhD), I really value looking at the scientific evidence rather than just accepting the claims made on health and fitness blogs. 

For that reason, as well as sharing what I've learned below, you'll find references to the studies I've read at the bottom of this article. 

What are BCAAs and Beta-Alanine?

The BCAAs are the amino acids leucine, isoleucine, and valine, essential nutrients found in protein-rich foods that play important roles in the human body, including in relation to muscle tissue repair, reducing exercise-induced muscle breakdown, and improving exercise performance. 

A BCAA supplement

Here's my 1-kg bag of BCAAs (tropical flavour). I usually have about 10 grams per day (two small scoops) when lifting or doing endurance training, so the bag will last a few months. I've got the 2:1:1 ratio (leucine, isoleucine, valine) version as it's a little cheaper than the 4:1:1 version. However, I might go for the 4:1:1 version next time, as the evidence suggests that leucine could be the main amino acid behind the athletic benefits associated with BCAAs

Beta-alanine is a naturally occurring amino acid (specifically, a beta-amino acid*) and popular dietary supplement known for its role in increasing muscle carnosine levels and potentially influencing nitric oxide production, which supports improved performance during high-intensity exercise by reducing lactic acid accumulation and enhancing power output. 

A beta-alanine supplement

Here's my 250-gram bag of beta-alanine

It looks like Myprotein and Bodybuilding Warehouse only have unflavoured versions of the powder. When I'm done with this bag, I might pick up the beta-alanine capsules on Bodybuilding Warehouse, as the flavour of supposedly unflavoured supplements is usually awful! When I next go for a long run, I'll mix some of this beta-alanine with the flavoured BCAAs. I see that Myprotein has put "Amino Acids: The Building Blocks of Protein" on the bag, which is usually accurate, but beta-alanine isn't one of the amino acids used to make proteins. 

This is arguably the main difference between BCAAs and beta-alanine. 

Body Composition

Supplementing with BCAAs has been linked to improvements in body composition. 

In a randomised, double-blind study (1) evaluating the impact of BCAA supplementation during an eight-week resistance-training programme, participants consuming 14 grams of BCAAs per day experienced greater improvements in body composition than those having 28 grams of carbs in the form of a sports drink. The BCAA group not only gained more lean mass but also showed a greater decrease in body fat. Furthermore, the BCAA-supplemented individuals exhibited superior strength gains in 10-rep max tests for both bench press and squat exercises.

An image representing lean muscle mass

Although a recent systematic review and meta-analysis suggested that beta-alanine does not have a positive effect on body composition (2), a study published in Nutrients found that combining beta-alanine with BCAAs led to a significant increase in fat-free mass among elite athletes (sprinters), suggesting that beta-alanine may enhance the effects of BCAAs on body composition (3i). 

So, can both BCAAs and beta-alanine be considered "muscle-building supplements"? It does seem that BCAAs play a role in building muscle, but it's not clear that beta-alanine increases lean muscle mass when taken by itself. 

Muscle Strength

As mentioned above, as well as improving body composition, BCAAs can increase strength (1), but what about beta-alanine? In one study (4), participants taking beta-alanine (6.4 grams per day), compared to placebo, showed significantly greater gains in strength over a five-week resistance training programme, as demonstrated in exercises like one-rep max back squat. Another study found that combining BCAAs and beta-alanine led to an 18% increase in one-rep max bench press compared to a 10% increase in the control group following an 8-week training programme (5). 

Muscle Protein Synthesis

Muscle protein synthesis refers to the incorporation of amino acids into muscle cells and plays a critical role in muscle growth. BCAAs, particularly leucine, activate molecular pathways that increase rates of muscle protein synthesis, especially after resistance exercise. However, the effect of BCAAs on muscle protein synthesis is less pronounced than that observed following ingestion of complete protein sources, like whey protein powder (6). Recent evidence from rodent studies suggests that combining BCAAs with vitamin B (B6) may further enhance muscle protein synthesis (7). 

With regards to beta-alanine, there doesn't seem to be evidence that this has a direct effect on muscle protein synthesis. 

Muscular Endurance

There's plenty of evidence that BCAAs and beta-alanine can help slow the onset of fatigue and maintain energy levels. 

A meta-analysis of 31 trials published in Sport Sciences for Health (8) found that BCAA supplementation reduced lactate and creatine kinase levels, which are markers of muscle fatigue and muscle damage, respectively. Regarding beta-alanine supplementation, 4–6 grams per day can enhance sports performance by attenuating neuromuscular fatigue, especially in older individuals (9). 

An image representing muscular endurance

Additionally, there's evidence that combining beta-alanine and BCAAs before exercise can significantly enhance lower-body muscular endurance and delay fatigue during an intense workout (10).

Thus, supplementing with either BCAAs or beta-alanine (or both) would be an effective way of experiencing less fatigue during exercise. 

Muscle Recovery

As touched on in the last section, there's also lots of evidence that BCAAs can minimise damage and recovery time. 

For example, in one study (11), it was observed that acute BCAA supplementation at a dosage of 0.087 g/kg body mass (e.g., about 7 grams for an 80-kilo person) significantly enhanced recovery in resistance-trained athletes following exercise-induced muscle damage and reduced perceived muscle soreness at 24 and 48 hours post-exercise compared to placebo. 

On the other hand, another study (12) found that beta-alanine supplementation did not improve muscle recovery following a single session of intense training with weights in untrained young adults, as indicated by similar outcomes in muscle function, soreness, and creatine kinase levels between the supplemented group and the placebo group. 

Athletic Performance

Both BCAAs and beta-alanine have been linked to enhanced athletic performance. 

For instance, one randomised controlled trial (13) found that BCAAs (0.17 g/kg; e.g., 13.6 grams for an 80-kilo person) 1 hour before testing significantly enhanced perceptual-motor performance and reduced central fatigue in male tennis players, resulting in higher accuracy and consistency in hitting balls after a simulated match compared to a placebo. Another study (14) found that beta-alanine supplementation over six weeks (6.4 grams per day) significantly improved athletic performance in young water polo players, as evidenced by enhanced ball-throwing velocity and 200-metre swimming performance

If you're interested in how supplements influence athletic outcomes, you might like our article on the benefits of creatine for different athletes.  

Immune System Function

Both BCCAs and beta-alanine have been linked to additional benefits less directly related to athletic performance benefits, such as improved immune function. 

A study published in Medicine & Science in Sports & Exercise (15) found that BCAA supplementation in elite triathletes maintained plasma glutamine levels post-competition, which contrasts with the decrease observed in the placebo group, suggesting an improved immune response by preventing exercise-induced glutamine depletion. This stabilisation of glutamine levels was associated with enhanced lymphocyte proliferation and cytokine production (IL-1), which could reduce the incidence of infection symptoms post-exercise,

Another study (16) found that beta-alanine supplementation (0.5 grams per day) for four weeks helped to maintain immune function after long-distance running by significantly reducing the level of the inflammatory cytokine IL-6 in male college students, compared to a placebo. 

Food Sources

As discussed at length in our article comparing egg and whey protein, both eggs and whey contain all essential and non-essential amino acids, so they are a good source of BCAAs. In fact, a single scoop of whey protein isolate or four eggs has at least as much of the essential nutrient leucine (the main ingredient in BCAA supplements) as a 5-gram scoop of a 4:1:1 BCAA powder. While soy protein isolate has a little less leucine than whey, it has similar amounts of isoleucine and valine (17). Other sources include milk, red meat, poultry, and rice (18). 

Eggs and whey protein

Similarly, beta-alanine is found in meat, poultry, and fish (19). However, unlike BCAAs, which are essential amino acids, beta-alanine is a non-essential amino acid that is synthesised in the liver (20). 

Potential Side Effects**

Exacerbation of Neurological Conditions?

BCAAs compete with other large amino acids to be transported into the brain. Since these other amino acids are precursors of important neurotransmitters (e.g., phenylalanine and tryptophan are precursors of dopamine and serotonin, respectively), BCAAs could influence neurotransmitter levels in the brain, which may exacerbate symptoms in conditions like schizophrenia (21) and amyotrophic lateral sclerosis. There is, however, no evidence that BCAA supplementation increases the risk of these conditions. 

Increased Insulin Resistance?

Higher BCAA levels in the blood are associated with an increased risk of insulin resistance, obesity, and diabetes (22). While it's possible that consuming more BCAAs increases the risk of such conditions, such as by increasing hunger (23), it's also possible that preexisting differences in how BCAAs are metabolised by those with such conditions lead to their accumulation (24). 

Tingling Sensation

In a study published in the International Journal of Nutrology (9), the only noted side-effect of beta-alanine was paraesthesia—itchiness or tingling in the skin that normally subsides within an hour. However, a systematic review of beta-alanine studies found that participants often weren't asked about side effects (25), so it's possible that these just haven't been undocumented. 

Artificial Sweeteners

Beta-alanine supplements are often unflavoured, in which case they're unlikely to contain artificial sweeteners. However, artificial sweeteners like sucralose and organic steviol glycosides (aka stevia) are among the most common ingredients in flavoured BCAA supplements. Research suggests that both of these sweeteners are safe (26, 27), though if you're concerned about these or other ingredients hidden in proprietary blends, you could opt for an unflavoured version. 

Different Supplements

I've also written about some of the other most common supplements and their evidence base, which might be of interest:


So, there's a decent amount of evidence that BCAAs and beta-alanine can play important roles in enhancing athletic performance, reducing fatigue, and supporting muscle recovery. BCAAs have been linked to muscle repair and reducing exercise-induced muscle breakdown, while beta-alanine increases muscle carnosine levels, helping to reduce lactic acid build-up during intense exercise. The combination of these supplements appears to offer synergistic effects, making them a powerful tool for achieving fitness goals like improving body composition and muscle strength. 

About the Author

Dave Robinson is a co-founder of ukfitness.pro and has a background in psychology (BSc) and neuroscience (MSc, PhD). As well as strength training, he enjoys endurance challenges and has completed marathons and 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. 

Foot Notes

*Essentially, beta-amino acids differ from alpha-amino acids in terms of their structure. The details of these differences are beyond the scope of this article, but there's a brief overview here

**Whether or not you have a medical condition, it's always best to talk to your doctor before starting a new supplement regime. 


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