Supplements · 4 min read ·

EAA: essential amino acids in a scoop

EAAs contain all nine amino acids the body cannot make on its own. Are they better than BCAAs — and worth it compared with ordinary protein?

EAA

In a nutshell

1What EAAs are

There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Three of them — leucine, isoleucine and valine — make up BCAAs, which have their own article.

Expert recommendation 0.7–3 g leucine The International Society of Sports Nutrition (ISSN): a 20–40 g dose of protein should contain 700–3,000 mg of leucine and a balanced mix of all essential amino acids. EAAs are what drives muscle protein synthesis, so foods with whole proteins are preferred.1

2Do they help muscles?

Moderate evidence — a randomised trial 10 g leucine Trained men eating 1.8 g of protein per kilo a day took 10 g of leucine daily during 12 weeks of strength training. Strength and muscle size grew just as much as with placebo.2
Moderate evidence A summary of studies in older people: leucine raised the rate of muscle protein synthesis but did not increase muscle mass compared with the control group.4
Weak evidence 39 studies A summary of 39 randomised trials with 4,274 older people with illnesses: protein and EAA supplements may have slightly improved muscle mass, strength and function. But the seven high-quality studies found no effect.3
Moderate evidence — a review of reviews 15 reviews A summary of 15 systematic reviews in people over 65: the best evidence is for leucine in people with muscle loss (sarcopenia) and for protein alongside strength training.5

3EAA or protein?

Weak evidence — one short study In a short-term study, a mix of free EAAs with whey raised protein synthesis per gram of product more than a whey drink did.6

For building muscle, 1.4–2.0 g of protein per kilo of body weight a day is enough for most athletes — from food or from protein powder.1

What to take from this

Sources

Written on , based on studies available at that date. Newer research may change the conclusions.

  1. Jäger R. et al. (2017). International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr 14:20. doi.org/10.1186/s12970-017-0177-8
  2. De Andrade I. T. et al. (2020). Leucine supplementation has no further effect on training-induced muscle adaptations. Med Sci Sports Exerc 52:1809–1814. doi.org/10.1249/MSS.0000000000002307
  3. Cheng H. et al. (2018). Systematic review and meta-analysis of the effect of protein and amino acid supplements in older adults with acute or chronic conditions. Br J Nutr 119:527–542. doi.org/10.1017/S0007114517003816
  4. Xu Z. R. et al. (2015). The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis. Br J Nutr 113:25–34. doi.org/10.1017/S0007114514002475
  5. Gielen E. et al. (2021). Nutritional interventions to improve muscle mass, muscle strength, and physical performance in older people: an umbrella review of systematic reviews and meta-analyses. Nutr Rev 79:121–147. doi.org/10.1093/nutrit/nuaa011
  6. Park S. et al. (2020). Anabolic response to essential amino acid plus whey protein composition is greater than whey protein alone in young healthy adults. J Int Soc Sports Nutr 17:9. doi.org/10.1186/s12970-020-0340-5
  7. Wolfe R. R. (2017). Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr 14:30. doi.org/10.1186/s12970-017-0184-9

This is general information and does not replace a doctor. Food supplements are not medicines; buy them from trusted sellers and talk to a doctor if you are ill or take medicines.