Athletes are constantly looking for the next big thing to help them up their game. Sometimes this search causes them to realize that the tried and true basics work best. The essential amino acids (EAAs) fall into the category of tried and true basics that work. EAAs have been a staple in the diets of hard training athletes for decades. An iconic scene from the movieRocky is of Rocky Balboa drinking raw eggs, and if you flip through the pages of old school bodybuilding magazines, many of the pros from the 60s and 70s used to swear by liver tablets. One thing that eggs and liver have in common is that they’re rich in EAAs. Here we’ll go over what EAAs are, what they do, and when to take them to optimize their results.
What are the Essential Amino Acids?
The EAAs consist of nine amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylethylamine, threonine, tryptophan, and valine. They’re called essential because our bodies can’t make them on their own but we need them to function, so they must be consumed from food or supplement sources. Food sources which are abundant in EAAs include beef, lamb, pork, tuna, poultry, eggs, yogurt, salmon, shrimp, soy, buckwheat, and quinoa. EAAs play a variety of roles in the body, including serving as building blocks for tissue growth. We’re going to focus on their role at promoting tissue growth, specifically muscle tissue.
What are the benefits of using Essential Amino Acids?
When it comes to athletes, their main intentions with EAAs is to aid in the building of new muscle tissue and emerging research shows it may even positively affect markers of recovery. It’s well-known that in order for the muscle to grow, the body must be in a positive muscle protein balance, which is where EAAs serve their purpose. Secondly, by supporting recovery, an athlete can be better primed to tackle their next training session.
Positive Muscle Protein Balance: When the rate of muscle protein synthesis is greater than the rate of muscle protein breakdown, our bodies are in a positive muscle protein balance. Being in a state of positive muscle protein balance is a favorable environment for building muscle. Researchers wanted to see the effects of EAA supplementation after a workout on net muscle protein balance. The researchers had subjects do a high-volume leg workout consisting of 10 x 10 leg presses and 8 x 8 leg extensions. The subjects supplemented with 6 g of EAAs, one and two hours after they trained. Blood samples were drawn from the subject’s legs and the researchers noted that EAAs favorably increased net muscle protein balance. 
A separate study was done examining the effects of EAA supplementation on muscle protein synthesis, except this time it was during steady state exercise. The researchers had subjects supplement with a leucine enriched EAA drink while they cycled for 60 minutes at 60% of their VO2 max. The researchers observed increased muscle protein synthesis and decreased muscle protein breakdown in subjects that supplemented with the leucine enriched EAAs compared to those who didn’t. 
Supports Muscle Recovery: Anyone who works out regularly understands the importance of recovery for achieving fitness goals. After a grueling workout, muscle strength and range of motion are decreased while muscle soreness is increased. All these factors combined can make it difficult to maintain the quality of your subsequent workouts. In a 2019 pilot study, researchers wanted to see if leucine enriched essential amino acids (LEAAs) could support muscle recovery. They had subjects perform an arm workout and supplement with 10.8 g of LEAAs daily for 7 days. Using blood tests, the researchers observed that LEAA supplementation suppressed exercise induced biomarkers of muscle damage. 
When should you take Essential Amino Acids?
After lifting: Taking EAAs after a workout has been shown to further augment the positive muscle protein synthesis effects of resistance training. After you weight train, your body is in a prime muscle-building state, and EAAs provide your body with the amino acids it needs.
During endurance workouts: Endurance training can be catabolic, and as a result many endurance athletes aim to feed their muscle mass by taking EAAs during long training sessions. Another benefit is that the EAAs are lighter on the stomach than consuming a complete protein source, like a whole food or a shake, easing the demands for digestion.
Between meals: Because EAAs can spike muscle protein synthesis, having a bolus of EAAs between meals can help promote a positive muscle protein balance throughout the day.
How many essential amino acids should you use?
Most research has shown 6-12 g of EAAs to be effective for muscle protein synthesis, in the absence of feeding.  These amounts have been used as a single dose as well as in split doses. An important point to note is that in studies, leucine enriched EAAs have been shown to be especially anabolic. When looking for an EAA supplement, you want to look for a formula that is leucine enriched. For individuals following vegan or vegetarian based diets who want to supplement with EAAs, look for essential amino acid products derived from vegan plant sources rather than animal by-products such as duck feather, pig fur or human hair.
If you’re looking to maximize your training and wish to support your body in muscle growth, EAAs, especially those enriched with leucine, are of value. Whether you wish to consume your serving in one dose or two, ensure you consistently use the supplement, paying attention to the post-workout timeframe.
, Borcheim, E., Tipton, K.D., Wolf, S.E. & Wolfe, R.R. (2002). Essential amino acids and muscle protein recovery from resistance exercise.Medicine & Science in Sports & Exercise, 34(5). doi:10.1097/00005768-200205001-01686
 Pasiakos, S.M., McClung, H.L., McClung, J.P., Margolis, L.M., Andersen, N.E., Cloutier, G.J., Pikosky, M.A., Rood, J.C., Fielding, R.A., & Young, A.J. (2011). Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis.The American Journal of Clinical Nutrition, 94(3), 809–818.
 Matsui, Y., Takayanagi, S., Ohira, T., Watanabe, M., Murano, H., Furuhata, Y., & Miyakawa, S. (2019). Effect of a leucine-enriched essential amino acids mixture on muscle recovery.Journal of Physical Therapy Science, 31(1), 95–101. doi:10.1589/jpts.31.95 Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger, R., . . . Kreider, R. B. (2018). ISSN exercise & sports nutrition review update: Research & recommendations.Journal of the International Society of Sports Nutrition, 15(1). doi:10.1186/s12970-018-0242-y