Amino acids, often referred to as the building blocks of proteins, are compounds that play many critical roles in your body.

You need them for vital processes such as building proteins, hormones, and neurotransmitters.

Amino acids are concentrated in protein-rich foods such as meat, fish, and soybeans.

Some people also take certain amino acids in supplement form as a natural way to boost athletic performance or improve mood. They’re categorized as essential, conditionally essential, or nonessential depending on several factors.

In this article, Pritish Kumar Halder describes all the basics about essential amino acids, including how they function, food sources rich in essential amino acids, and the potential benefits of taking a supplement.

What are essential amino acids?

Amino acids are organic compounds composed mainly of nitrogen, carbon, hydrogen, and oxygen.

Your body needs 20 different amino acids to grow and function properly. While all 20 of these are important for your health, only 9 are classified as essential.

These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Although your body can make nonessential amino acids, it cannot make essential amino acids, so you have to get them from your diet.

The best sources of essential amino acids are animal proteins such as meat, eggs, and poultry. However, some plant foods, such as the soy products edamame and tofu, contain all nine essential amino acids. This means they are “complete” sources of protein.

After you eat protein, your body breaks it down into amino acids and then uses them for various processes, such as building muscle and regulating immune function.

essential amino acids

Conditionally essential amino acids

Several nonessential amino acids are classified as conditionally essential.

These are essential only under specific circumstances, such as during illness, pregnancy, infancy, or trauma. For example, arginine is considered nonessential, but your body can’t make as much as you need when you’re healing from a serious injury or fighting certain diseases, such as cancer.

That’s why, in certain situations, people may take arginine supplements to meet their bodies’ needs.

Additionally, certain amino acids, including glycine and arginine, are considered conditionally essential during pregnancy because a pregnant person needs more of these amino acids to support their own health and the health of the fetus.

Food sources and recommended intake

Because your body cannot produce essential amino acids, it’s important to get them through your diet. Many foods are rich in essential amino acids, making it easy to meet your daily needs.

Here are the daily required intakes for the essential amino acids, according to the World Health Organization. These are for adults per 2.2 pounds (1 kg) of body weight (29):

  • Histidine: 10 mg
  • Isoleucine: 20 mg
  • Leucine: 39 mg
  • Lysine: 30 mg
  • Methionine: 10.4 mg
  • Phenylalanine combined with the nonessential amino acid tyrosine: 25 mg
  • Threonine: 15 mg
  • Tryptophan: 4 mg
  • Valine: 26 mg

To find out how much you should consume per day, you can multiply the numbers given above by your weight in kilograms. For example, a person who weighs 60 kg (132 pounds) should consume 1,200 mg (1.2 grams) of isoleucine per day.

Meeting these requirements is very easy with most diets, so there’s usually no need to track your intake of individual amino acids. For example, one 174-gram piece of braised chicken breast provides 55.9 grams of complete protein, easily meeting or exceeding the needs listed above.

Food sources

Foods that contain all nine essential amino acids are referred to as complete proteins.

The following foods are complete protein sources:

  • meat
  • seafood
  • poultry
  • eggs
  • dairy products

Soy and pea protein are plant-based complete protein sources.

Other plant-based sources of protein, such as beans, nuts, and certain grains, are considered incomplete proteins because they lack one or more of the essential amino acids.

However, if you’re following a plant-based diet, you can still ensure proper intake of all nine essential amino acids by eating a variety of plant proteins each day.

For example, choosing a variety of plant-based proteins, such as beans, nuts, seeds, whole grains, and vegetables, can ensure that you meet your essential amino acid needs, even if you choose to exclude animal products from your diet.

How to supplement with essential amino acids

Most people get enough essential amino acids through their diet.

However, there are some benefits to taking essential amino acid supplements. For example, athletes often take them to enhance exercise performance and recovery.

One review that included 10 high quality studies found that doses of BCAAs of up to 115.6 mg per pound (255 mg per kg) per day could help reduce delayed onset muscle soreness in trained individuals after exercise.

Additionally, people may choose to take individual amino acids, rather than blends, to support certain aspects of health, such as mood.

A review that included 11 high quality studies found that taking 0.14–3 grams of tryptophan per day could help improve mood in healthy people.

As you can see, dosing varies depending on the type of amino acid you’re taking and what your goal is. Amino acid supplements are considered safe for most people. However, they’re usually not necessary if you’re getting enough protein in your diet.

Nonetheless, amino acid supplements may offer certain benefits for specific groups of people.

If you’re interested in taking essential amino acid supplements, speak with a healthcare professional who’s knowledgeable about dietary supplements, such as your doctor or a registered dietitian.

They can recommend specific dosing and tell you how best to take your supplement, depending on your health goals. Additionally, they can help you choose a supplement from a reputable brand that offers products tested by third-party organizations.