BCAAs in Endurance Fuels – A Suboptimal Solution

BCAAs in Endurance Fuels – A Suboptimal Solution

BCAAs in Endurance Fuels


As an endurance athlete, you’ve probably noticed that you’re starting to see more and more endurance fuels that contain BCAAs.  

It makes sense that endurance supplement companies are thinking of creative ways to incorporate BCAAs into their supplements. After all, BCAAs have been shown to have various benefits for endurance athletes, including;

  • Preventing excess muscle breakdown during endurance exercise (Fouré & Bendahan, 2017)
  • Preventing mental fatigue during endurance activity (AbuMoh’d et al., 2020)
  • Increasing time to exhaustion during endurance activity (AbuMoh’d et al., 2020)
  • Glycogen sparing (Monirujjaman & Ferdouse, 2014) and improved glycogen replenishment (Van Loon et al., 2000)
  • Reduces exercise-induced cortisol (Tsuda et al., 2020)
  • Improve BCAA: tryptophan ratio (Kephart et al., 2016) – thought to be a significant contributor to overtraining syndrome

That’s an impressive list of endurance-related benefits. It’s no wonder BCAAs are becoming more and more common in endurance supplements.

However, in my opinion, an endurance fuel is not the optimal approach to supplement BCAAs for endurance athletes.

The Problem with BCAAs in Endurance Fuels

The issue with BCAAs in endurance fuels is that I don’t believe that you’re ever going to take in ENOUGH BCAAs to optimally produce many of the previously mentioned benefits.

Let’s look at what the scientific literature says about BCAAs, and how much is required to accomplish the above benefits.

Study Example #1 – The study mentioned above on trained cyclists by Kephart et al. (2016) found that 12 grams per day of BCAA supplementation for 10 weeks improved the post-study BCAA: tryptophan ratios compared to the placebo group. This isn’t all that improved in the ten weeks either. Endurance performance was also improved, and the neutrophil response was blunted – likely resulting in improved immunity.

Study Example #2 – A systematic review by Fouré & Bendahan (2017) concluded that “BCAAs can be efficacious on outcomes of exercise-induced muscle damage.” But here’s the more significant point – Fouré & Bendahan (2017) went on to say that BCAA supplementation is most effective when taken DAILY and in high amounts, about 200 mg/kg/day*  for at least 10 days. Finally, they were especially effective when taken BEFORE damaging exercise.

*200 mg/kg would be about 13.5 grams of supplemental BCAAs (daily) for a 150 lb. athlete.  

Study Example #3 – 7 grams of BCAAs given before exercise improved the reaction time of soccer players after two 45 minute treadmill sessions (Wiśnik et al., 2011).

Study Example #4 – Blomstrand et al. (1997) performed a study on male endurance-trained cyclists. The cyclists performed 60 minutes of exercise at 70% of their V02 max, followed by 20 minutes of maximal effort. Perceived exertion of the BCAA group was 7% lower than that of the placebo group. Additionally, mental fatigue was 15% lower in the BCAA group. Lastly, the tryptophan: BCAA ratio was increased by 150% after exercise in the placebo group, while the BCAA group’s tryptophan: BCAA ratio was either unaffected or improved. The researchers used 90mg/kg of BCAAs in this study. Again, using a 150 lb. athlete, this amount would equate to about 6.1 grams of total BCAAs.

Study Example #5 – A high intake of BCAAs (20 grams) taken 1-hour before endurance exercise increased time to exhaustion in male long-distance runners (AbuMoh’d et al., 2020).  

There’s a lot more out there too, but I think you get the point. Looking at the body of evidence, I would conclude that BCAA supplementation has shown to be the most effective (all benefits included) for endurance athletes when taken in the following manners;

  1. When taken before damaging exercise
  2. When taken in amounts ranging from 7-20 grams
  3. When taken daily for periods of at least 10 days

So, with these things in mind, let’s look at a couple of different endurance fuel supplements that incorporate BCAAs. As always, I won’t mention names.

Examples of Endurance Fuels Containing BCAAs

Endurance fuel #1 – This fuel provides 250mg of BCAAs/serving (120 kcal/serving). If taken on the high-end of what most people can handle as far as calorie intake/hour (360 kcal) during endurance exercise, this would amount to about 750 mg of BCAAs/hour. So in a 4-hour endurance activity, one would acquire about 3 grams of BCAAs.

With this fuel, an endurance athlete is getting less than half of what studies show to be effective (and that’s at 4 hours of activity). Remember, NONE of these studies examined 4-hour endurance efforts (they were all shorter).

Endurance fuel #2 – Another endurance fuel provides 600 mg of BCAAs per 280 calorie serving. They recommend taking in one serving for every 60-90 minutes of exercise. If taken at the higher rate of 1 serving/hour, this would equate to less than endurance fuel #1.

Additionally, much of the BCAAs in endurance fuel #2 come from whey protein.  This is a little off topic, but I would never recommend using whey in an endurance fuel for a few reasons.  

First, MANY people are intolerant to whey, so including it in an endurance fuel is just asking for gastrointestinal issues during a time when the GI system is already overly sensitive. Second, complete proteins (like whey) can slow down the digestive process, which is why BCAAs are recommended rather than complete proteins.

Indeed, some complete protein is recommended in ultra-endurance length efforts. However, including it in an endurance fuel is not the answer. Instead, it’s best to have the ability to base it on how your stomach feels at the time.  It’s much more effective and easier on the stomach to supplement with BCAAs and take in a little bit of complete protein when tolerable – either in the form of real food or (my preference) a recovery formula like Terminus.

Am I saying that the amount of BCAAs in these endurance fuels is useless? No, of course not. I’m sure they slow things down a bit, but according to science, not even close to optimally. So why don’t they put more BCAAs in endurance fuels? Well, one reason is likely because of taste. If you’ve ever tried raw BCAAs, you know what I’m talking about – BCAAs taste (and smell) BAD.  

Two of the most significant issues relating to intra-workout nutrition in ultra-running and extended duration endurance sports are nausea and palate fatigue. The more BCAAs an endurance supplement company includes in an endurance fuel, the more “flavor” they have to include to mask the disgusting taste of those BCAAs. 

An endurance fuel should be mildly flavored to reduce the risk of palate fatigue. Too many BCAAs and too little flavor and it will taste disgusting, all but guaranteeing nausea.  Therefore, you see the dilemma.

Even IF an endurance fuel does somehow manage to include adequate amounts of BCAAs/serving and somehow make it taste good, the athlete is still 100% reliant on consuming that fuel to reap the benefits of BCAAs. 

Additionally, studies show that BCAAs work best when taken DAILY, not just during endurance exercise. It doesn’t make sense, nor is it recommended to take in endurance fuels outside of training, so this means you must find another source for BCAAs on rest and recovery days. This makes things overly complicated, in my opinion.  

A Better Solution for Endurance Athletes

A far superior way for endurance athletes to consume optimal amounts of BCAAs is to consume them separate from their fuel. There’s no substantial evidence to suggest that “spreading out” the intake of BCAAs is superior to taking larger doses less often. In fact, most of the studies on BCAAs for endurance athletes have used larger quantities of BCAAs taken less often and primarily before endurance exercise.  

Rather than the amount of BCAAs taken during endurance exercise being solely dependent upon how much fuel an athlete consumes, why not just take the optimal amount in prior, and if necessary (in the case of long-endurance sessions like ultramarathons), again during exercise?

Summary – BCAAs in Endurance Fuels

There’s not much doubt that BCAAs are an effective endurance supplement, but like any other supplement, they must be taken appropriately if you hope to reap the benefits.

Just including BCAAs anywhere and in any amount doesn’t cut it. The dose, timing, and frequency must be appropriate to reproduce the endurance-related benefits seen in the scientific literature. For this reason, taking BCAAs via an endurance fuel is suboptimal, in my opinion.  

The Best BCAA Supplement for Endurance Athletes – T-30


T-30 is the ultimate endurance supplement for serious athletes. T-30 contains 10 grams of vegan BCAAs and is meant to be taken daily and before exercise. As mentioned previously, this is a far superior way for endurance athletes to ensure they’re getting sufficient BCAAs and to take advantage of all the benefits BCAAs offer.

By the way, T-30 is A LOT MORE than a BCAA supplement – to learn more about the various benefits of T-30, check out T-30 – The KING of Endurance Supplements




AbuMoh’d, M. F., Matalqah, L., & Al-Abdulla, Z. (2020). Effects of Oral Branched‐Chain Amino Acids (BCAAs) Intake on Muscular and Central Fatigue During an Incremental Exercise. Journal of Human Kinetics, 72(1), 69–78. https://doi.org/10.2478/hukin-2019-0099
Blomstrand, E., Hassmén, P., Ek, S., Ekblom, B., & Newsholme, E. A. (1997). Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise. Acta Physiologica Scandinavica, 159(1), 41–49. https://doi.org/10.1046/j.1365-201X.1997.547327000.x
Fouré, A., & Bendahan, D. (2017). Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review. Nutrients, 9. https://doi.org/10.3390/nu9101047
Kephart, W. C., Wachs, T. D., Thompson, R. M., Brooks Mobley, C., Fox, C. D., McDonald, J. R., Ferguson, B. S., Young, K. C., Nie, B., Martin, J. S., Company, J. M., Pascoe, D. D., Arnold, R. D., Moon, J. R., & Roberts, M. D. (2016). Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists. Amino Acids, 48(3), 779–789. https://doi.org/10.1007/s00726-015-2125-8
Kim, D.-H., Kim, S.-H., Jeong, W.-S., & Lee, H.-Y. (2013). Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substances. Journal of Exercise Nutrition & Biochemistry, 17(4), 169–180. https://doi.org/10.5717/jenb.2013.17.4.169
Monirujjaman, M., & Ferdouse, A. (2014). Metabolic and Physiological Roles of Branched-Chain Amino Acids. Advances in Molecular Biology, 2014, e364976. https://doi.org/10.1155/2014/364976
Tsuda, Y., Murakami, R., Yamaguchi, M., & Seki, T. (2020). Acute supplementation with an amino acid mixture suppressed the exercise-induced cortisol response in recreationally active healthy volunteers: A randomized, double-blinded, placebo-controlled crossover study. Journal of the International Society of Sports Nutrition, 17(1), 39. https://doi.org/10.1186/s12970-020-00369-2
van Loon, L. J., Saris, W. H., Kruijshoop, M., & Wagenmakers, A. J. (2000). Maximizing postexercise muscle glycogen synthesis: Carbohydrate supplementation and the application of amino acid or protein hydrolysate mixtures. The American Journal of Clinical Nutrition, 72(1), 106–111. https://doi.org/10.1093/ajcn/72.1.106
Wiśnik, P., Chmura, J., Ziemba, A. W., Mikulski, T., & Nazar, K. (2011). The effect of branched chain amino acids on psychomotor performance during treadmill exercise of changing intensity simulating a soccer game. Applied Physiology, Nutrition, and Metabolism = Physiologie Appliquee, Nutrition Et Metabolisme, 36(6), 856–862. https://doi.org/10.1139/h11-110

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