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Hands holding essential amino acid capsules and protein powder


No. Although essential amino acids (EAAs) are the building blocks of protein, there is no evidence that consuming free EAAs helps build muscle better in healthy individual than consuming "complete" or "high-quality" protein, that is, protein that contains all essential amino acids.

Many studies show that eating high-quality protein can increase muscle mass and strength when combined with resistance exercise; however, consuming EAAs alone (in free form rather than combined as protein) might not be as beneficial as protein. For example, a study among elderly adults involved in resistance training who supplemented with protein (in the form of a whey protein isolate) or free form EAAs showed that slightly more amino acids obtained from the protein were incorporated into muscle protein compared to EAAs from the free-form supplement (Kerksick, J Int Soc Sports Nutr 2018).

It should be noted that there is some evidence that EAAs may be somewhat more effective than protein at improving muscle strength in older adults with acute or chronic conditions not involved in exercise, such as those in nursing homes and hospitals (Cheng, Br J Nutr 2018).

Interestingly, while the ability of EAAs to promote protein synthesis has been largely attributed to three specific EAAs called branched chain amino acids (BCAAs), which consist of leucine, isoleucine, and valine, a study showed that taking free-form BCAAs was slightly less effectively than taking free-form EAAs (which included BCAAs along with other EAAs) in promoting protein synthesis (Moberg, Am J Physiol Cell Physiol 2016). Furthermore, although BCAAs may help reduce loss of muscle during long periods of muscle disuse in some settings, the evidence is mixed as to whether BCAAs boost muscle strength.

Information about the pros and cons of different types of protein found in supplements — including whey, casein, soy, and rice and their various marketed forms (such as concentrates, isolates, hydrolysates, and ion-exchange purified products) — is found in the ConsumerTips section of our Protein Powders, Shakes, and Drinks Review. The Review includes our tests and comparison of popular protein powders and our Top Picks among them. Also see our Protein Bars Review.

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September 22, 2020

My subscription to ConsumerLabs.Com has been one of the best decisions I’ve made with regard to mine and my family’s health. It’s an absolute plethora of information all at one site. I no longer have to scour the Internet for the latest information regarding supplements thus savIng time and money. I highly recommend Consumer Labs
September 30, 2020

Thank you for your kind words. We are glad you are enjoying the site!

September 20, 2020

What are most of these EAA supplements made from?
Are they synthetic or from plant or animal sources?
September 28, 2020

Great question! EAA supplements can be produced by several methods, including extraction from protein that has been broken down, fermentation, and synthesis (using either chemical reactions or enzymes). The pros and cons of each method are summarized in this article:

September 13, 2020

Your answer is only correct if one is getting about 3 g leucine per meal. Less than that and muscle protein synthesis drops off. To compensate for a low leucine diet, additional BCAAs with 5 g leucine can evidently help. See
September 28, 2020

The study you provided did show that a low-dose protein supplement fortified with leucine-enriched BCAAs can be beneficial for muscle protein synthesis, but it was not superior to high-dose protein (whey). However, as we note in our answer above, there are indeed situations (such as in elderly people who are hospitalized and undernourished) in which BCAA/EAA supplements providing about 2.5 grams of leucine might be more beneficial than protein.

September 13, 2020

I tried switching from protein powder (ON 100% Whey) to EEAs for a month - that resulted in a loss of muscle mass. Not a good thing for a 80 year old who strength trains and has lifted for 60 years. I'll stick with the protein powder. It works.

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