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All You Need To Know About EAA (Essential Amino Acids) Supplements

The word EAA, or essential amino acids, gets thrown around a lot in the health and fitness world. Even though these supplements keep spreading like wildfire, few people truly understand what they are taking and why it is important for their bodies. 

The thing is, once you gain an understanding of what essential amino acids truly are, you will also understand what to look for when you are buying an EAA supplement for yourself. 

Not only will that information be helpful in finding the best EAA supplement, but you will also avoid taking something your body doesn’t actually need. 

Let’s start with the basics: 

Essential Amino Acids Explained

Essential amino acids are a group of nine amino acids that cannot be produced by the human body (hence the name “essential”) and must be obtained through the diet. These amino acids are essential for protein synthesis and a variety of other bodily functions. 

The nine essential amino acids are:

  1. Histidine
  2. Isoleucine
  3. Leucine
  4. Lysine
  5. Methionine
  6. Phenylalanine
  7. Threonine
  8. Tryptophan
  9. Valine

These amino acids are considered “essential” because the body cannot produce them on its own, so they must come from food sources.

Unfortunately, a diet that lacks any of these essential amino acids can lead to a variety of health problems, including poor growth, muscle wasting, and impaired immune function.

So in short, you will not be your healthiest self.

Therefore, it’s really important to consume a balanced diet that contains all of the essential amino acids or to supplement your diet with EAAs to ensure that you are getting more than enough of them.

How many Amino Acids Are there?

There are 20 different amino acids that are commonly found in proteins and used by the human body. These 20 amino acids can be put into three different groups based on their chemical and structural properties:

Essential amino acids:

These are the 9 amino acids that cannot be produced by the body and must be obtained through the diet. 

Nonessential amino acids: 

Nonessential amino acids are the 11 amino acids that can be produced by the body and do not need to be obtained through the diet.

The nonessential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine.

Conditionally essential amino acids: 

Conditional amino acids are amino acids that are normally nonessential but may become essential under certain conditions, such as during periods of illness or stress.

The conditionally essential amino acids are ​​arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine. 

The 20 amino acids are:

  • Alanine
  • Arginine
  • Asparagine
  • Aspartic acid
  • Cysteine
  • Glutamic acid
  • Glutamine
  • Glycine
  • Histidine
  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Proline
  • Serine
  • Threonine
  • Tryptophan
  • Tyrosine
  • Valine

These amino acids are the building blocks of proteins, and the order and type of amino acids in a protein determine its structure and function.

How many Essential Amino Acids are there?

As mentioned above, there are 9 essential amino acids that the body cannot produce on its own: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. 

The so-called BCAAs (branch-chained amino acids) are particularly important for muscle building as they reduce protein breakdown and increase metabolism. You will see supplements for BCAAs and EAAs in a lot of health stores. 

EAAs and BCAAs are both types of amino acids, but they differ in their properties and functions. BCAAs (branched-chain amino acids) are a subset of EAAs that include three specific amino acids: leucine, isoleucine, and valine. 

They are called “branched-chain” amino acids because their chemical structure includes a branched chain of carbon atoms.

BCAAs are often used by athletes and bodybuilders to increase their muscle growth and improve exercise performance. Sometimes, they are also used in medicine to prevent muscle wasting (atrophy) in patients with certain conditions.

Now, while BCAAs are often marketed as a supplement to enhance athletic performance and muscle growth, sticking to only BCAAs may not be enough to support the body’s needs for protein synthesis and other functions. It’s better to consume a balanced mix of all nine EAAs to support overall health and fitness.

So, what do the 9 Essential Amino Acids do? 


Histidine is an essential amino acid which helps regulate the acid-base balance in the body. It also plays an important role in the formation of histamine, a neurotransmitter that is involved in immune response, digestion, and sleep-wake cycles. But that’s not all, it is also important for immune function, as it is involved in the production of white blood cells and antibody responses.


Isoleucine is an essential branched-chain amino acid. It is important for energy production, muscle building, the immune system, and wound healing. It is one of the three branched-chain amino acids (BCAAs) that are metabolized directly by muscle tissue, and it can be converted to acetyl-CoA, a molecule that is involved in the production of energy in the body. 


Leucine is an essential branched-chain amino acid. It is important for energy production, muscle building, and wound healing. One of the primary functions of leucine is to stimulate muscle protein synthesis. This process is important for muscle growth and repair, and it can help to prevent muscle breakdown.


Lysine is an essential amino acid important for the body’s absorption of calcium, immune system regulation, and regulation of hormones. Because of that, it is particularly important for the growth and repair of tissues, including bones and muscles.

One of the most well-known functions of lysine is its role in the prevention and treatment of cold sores. This is because lysine can help to suppress the replication of the herpes simplex virus, which is responsible for cold sores.


Methionine is an essential amino acid important for the body’s absorption of calcium and for the synthesis of certain hormones and proteins. It is a sulfur-containing amino acid and is involved in many metabolic processes, including the production of energy and the regulation of antioxidant activity. And the best part? It’s great for your hair, skin, and nails! 


Phenylalanine is an essential amino acid important for cognitive function, energy production, and the formation of new cells. It is used for chronic pain, ADHD, depression, and ageing skin, but unfortunately, the research does not yet support all its functions. 


Threonine is an essential amino acid  important for the synthesis of collagen, elastin, and other proteins. This amino acid is particularly important for the growth and repair of tissues, including bones and muscles. Threonine is also involved in the regulation of the nervous system.

On top of all that, this EAA is important for the metabolism of fats and can help to prevent the buildup of fat in the liver. It is involved in the synthesis of phospholipids, which are important components of cell membranes.


Tryptophan is an essential amino acid important for the production of serotonin, melatonin, and other hormones. Serotonin is a neurotransmitter that is involved in the regulation of mood, appetite, and sleep. You might know Melatonin as a regulator of the sleep-wake cycle. 


Valine is a branch-chained essential amino acid important for energy production, metabolism, and muscle growth. Just like some other Essential Amino Acids, Valine is also involved in the regulation of the nervous system.

Natural Sources of EAAs

Did you know that you don’t necessarily need to take a supplement to get all of your EAAs? There are some natural sources of essential amino acids

The best source of Essential amino acids will be found in animal proteins such as beef, poultry, or eggs. 

Do you already know the difference between complete and incomplete proteins? 

Complete proteins are proteins that contain all 9 of the essential amino acids. Some examples of complete proteins are:

  • Poultry
  • Beef
  • Pork
  • Fish
  • Eggs 
  • Dairy
  • Soy (Tofu, Tempeh, Miso, Edamame) 

Incomplete proteins contain a few, but not all of the essential amino acids your body needs. Some examples of those are: 

  • Nuts and Seeds
  • Legumes (Beans, Lentils, Peas) 
  • Vegetables
  • Whole Grains 

The good news is that you don’t have to stick to complete proteins, you can switch things up and complete all kinds of proteins for a rich, diverse diet. 

To give you a better idea of how much of the EAAs you can find in food, one serving (4oz) of ground beef contains 10.042 grams of Essential Amino Acids. 

If you eat one egg, it contains 2.8 grams of EAAs. Now, you might be already supplementing EAAs without being aware of it! You see, Whey protein powder, for example, consists of 43% essential amino acids! With a typical scoop size of 25 grams, that leaves you with more than 10 grams of EAAs per serving! This is a lot higher than plant-based alternatives. Oat protein, for instance, only consists of 21% EAAs. 

Essential Amino Acid Supplements

Okay, so after hearing all that information on Essential Amino Acids, why do you need a supplement? Well, for starters, it yields quite a few benefits, both as an athlete and also for your general well-being: 


  • Muscle growth 
  • Enhance recovery 
  • Improve athletic performance 
  • Improve mental focus 
  • Promote healthy digestion 
  • Help reduce fatigue 
  • Improve mood and sense of well-being

Recommended Dosage

When it comes to dosage, the standard dose is 3 grams, whereas the maximum recommended dose is up to 15 grams. However, there are more detailed recommendations on how much of each EAA you should consume: 

For every 2.2 pounds of your body weight, you should get the following: 

  • Histidine: 14 milligrams
  • Isoleucine: 19 milligrams
  • Leucine: 42 milligrams
  • Lysine: 38 milligrams
  • Methionine: 19 milligrams
  • Phenylalanine: 33 milligrams
  • Threonine: 20 milligrams
  • Tryptophan: 5 milligrams
  • Valine: 24 milligrams


Essential Amino Acids are important for the body, whether that’s on a normal day-to-day basis, to improve athletic performance, to increase muscle mass and help with weight gain, or to feel better and more energized.

You can get all of your essential amino acids through a healthy, balanced diet, but there are also a ton of essential amino acid supplements you can take to make sure you are hitting that goal every single day.

Anna Scheucher
Editor at The Fitness Tribe | + posts

Anna is our massage, recovery, nutrition, and training specialist. She holds a degree in Medical Massage Therapy from the Bergler Massage Institut and a Personal Trainer and Nutritionist degree from the OTL Academy. She is originally from Austria but lives in the U.S and when she is not writing science backed articles for you can find her globe trotting around the world.

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