BCAA for Runners: Should Runners Use Branched Chain Amino Acids?

Written by Ben Carlisle

Last updated on: Sep 18, 2022

Kimura Athletic may earn a small commission through our links. Learn more.

Branched chain amino acids (BCAA's) are a supplement that has been found to have numerous benefits for exercise and is especially popular for people trying to build muscle. However, should runners use branched chain amino acids? We have the answer!

image 1

BCAAs have been found to reduce fatigue by preserving your body’s glycogen stores, meaning that the fuels used by your body for running will be delivered to your muscles more efficiently. When used as a supplement with a carbohydrate heavy diet, they reduce post­race fatigue and inhibit cortisol.

If you’re a runner, your exercise goals are very different to those of someone who focusses on strength training, for example, which is where BCAAs are especially useful, due to their ability to promote muscle growth. So, if muscle growth isn’t your priority, but endurance and recovery are, what kind of effect will BCAAs have on your performance?

What Are BCAAs?

Branched chain amino acids are essential acids that are naturally used by your body, can be found in numerous food sources and can be taken as a supplement to reduce muscle pain, improve power output, increase stamina and lose weight.

The three BCAAs that are relevant for your exercise regime are leucine, isoleucine, and valine (1, 2), which stimulate protein synthesis and therefore muscle growth and recovery. They serve as a catalyst and oxidization process that elevates countless factors determining the results of your workout, primarily muscle signalling and activating metabolic pathways that influence the way that your body reacts to exercise and your dietary habits.

Benefits of BCAA’s

BCAAs are a highly effective supplement that have been scientifically proven to have a number of critical benefits that could make a huge difference not only in the gym, but for runners too.


Using BCAAs to supplement your fitness regime has been demonstrated to decrease serum concentrations of creatine kinase and lactate dehydrogenase after prolonged periods of exercise, which means that the muscle damage cause by endurance exercises like running is reduced (4).

Reduced Fatigue

BCAAs also help to regulate your body’s tryptophan levels and restores seratonin, which helps to reduce fatigue and improve your mental focus while running (5).

Muscle Maintenance

BCAAs also activate enzymes that maintain lean muscle mass, which means if you’re running on a caloric deficit, your body will burn carbohydrates and body fat, but will not breakdown muscle tissue (3).

Muscle Growth

Because BCAAs aid with protein synthesis, the method through which your body processes protein to build muscle, they have found to be an incredibly effective supplement for muscle growth. This could, however, hinder runners who are trying to retain a lean physique (3).

Can BCAA’s improve The Performance of Runners?

Many runners will be wondering how the benefits that BCAAs bring would improve their performance on the road (or track, or treadmill).

In a study conducted with 28 100km ultra-marathon runners, it was found that BCAAs had no observable effects on performance, skeletal muscle damage or renal function (6). Another study found that supplementing BCAAs over a seven day period was ineffective at preventing muscle damage (7). However, supplements with high concentrations of leucine were effective at improving blood amino concentration, but it did not have an effect on performance. However, another study found that it does aid protein synthesis in runners, allowing them to build more muscle mass in activated muscles (8).

Will BCAAs make you a faster runner?

Simply put, BCAAs, taken in isolation, will not make any difference to your running speed, but your times will improve due to the reduced levels of fatigue and the ability to run at a moderate pace for longer. It will also aid in muscle mass retention while losing weight, which could result in better performance in the long run (8).

To put it succinctly, BCAAs will not improve your performance overnight, but they will aid in the growth and maintenance of lean muscle mass, which will ultimately make you a stronger runner. They will also improve your fatigue, which will allow you to run at higher paces for longer.

BCAAs also reduce delayed onset muscle soreness (DOMS) and exercise induced muscle damage (EIMD) (5) which will allow you to recover after an exceptionally long run that would have kept you out of action for longer and therefore affect your results.

Are BCAA’s Suitable For Vegans and Vegetarians

The primary reason that BCAAs are so effective is because they activate and enhance protein synthesis. This, however, requires a high protein diet – which is very difficult to follow if you’re not eating any meat. Furthermore, most BCAAs will contain trace amounts of animal fur, feathers, and human hair for keratin.

However, there are some BCAAs that are vegan friendly and are sourced from soy or corn. But the tough part is that many plant-based BCAAs will contain GMOs and can trigger allergic reactions (9).

Some vegans swear by BCAAs, however, and insist that they need to be included in your diet, because there are far lower concentrations of all essential amino acids in plant-based diets, compared to a diet that contains regular servings of meat.

However, legumes, such as soy beans, lentils and chickpeas, and nuys are great sources for BCAAs and you should try to introduce them to your diet (9). Furthermore, you should supplement your diet with plant-based protein powder, so that your body has enough protein to synthesize.


It’s no wonder that  BCAAs have become such a popular supplement for athletes, considering the plethora of ways in which it can aid muscle growth and maintenance, reduce fatigue and shorten recovery periods.

However, when it comes to running, the effects that it has on your performance in the short term appear to be minimal. In the long-term, as a consequence of healthy muscle mass and improved endurance, your running performance may improve, but there’s not a lot of evidence to support this due to limited studies being available.

Nonetheless, there aren’t any downsides to runners using BCAAs and it’s certainly worth the effort to use their clinically proven performance enhancing attributes to your advantage and to get an edge over your competition.

Related Articles


1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5568273/

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1855657/

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5568273/

4. https://pubmed.ncbi.nlm.nih.gov/11125767/

5. https://pubmed.ncbi.nlm.nih.gov/25566428/

6. https://pubmed.ncbi.nlm.nih.gov/23007065/

7. https://pubmed.ncbi.nlm.nih.gov/24477835/

8. https://academic.oup.com/ajcn/article/94/3/809/4411863

9. https://pubmed.ncbi.nlm.nih.gov/29087622/

View More Articles