9 Essential Amino Acids: Why You Need Them and Where They Are Found

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In medical terminology, “essential” means that a substance is required for proper health but also cannot be produced by the body, such as with many vitamins, amino acids, digestive enzymes, and more. Some of these essential parts of a healthy diet and lifestyle are well known while others are more obscure.

Protein is a compound that the body needs, and it’s discussed frequently. What most people don’t know is that proteins are made up of amino acids—organic compounds that the body needs to help it process food, grow, and more. These crucial compounds deserve a closer look.

What Are Amino Acids?

Amino acids combine to form proteins. They’re often called the building blocks of life. They’re not just needed to create proteins, they also are necessary for the synthesis of hormones and neurotransmitters, and they can be used as energy.

There are 21 kinds of amino acids, and they are classified into three different groups.

1. Nonessential Amino Acids

These amino acids are necessary, but the body can make them itself, so they’re not needed in your diet. The name nonessential amino acid can be misleading or confusing. The six nonessential amino acids are:

♦ Arginine

♦ Cysteine

♦ Glutamine

♦ Glycine

♦ Proline

♦ Yrosine

2. Conditionally Essential Amino Acids

Under normal situations these amino acids are considered nonessential but under specific situations your body needs them to fight illness or stress. The six conditionally essential amino acids are:

♦ Alanine

♦ Aspartic acid

♦ Asparagine

♦ Glutamic acid

♦ Serine

♦ Selenocysteine

3. Essential Amino Acids

These nine amino acids cannot be made by the human body, so they need to come from other sources, typically they’re sourced from food. The essential amino acids are:


Much like the name suggests, histidine is necessary to produce histamine. While people with allergies may get frustrated with their body’s histamine responses, it’s actually vital in many ways.

Histamine is a neurotransmitter that’s key for immune response, digestion, sexual function, and sleep cycles. It also helps maintain the protective myelin sheath barrier around your nerves.

Found in: Red meat, cheese, white meat and poultry, seafood, soybeans, beans, legumes, chia seeds, buckwheat, and potatoes.


This is a branched-chain amino acid that is mainly found in your muscle tissue. It regulates muscle metabolism, plays a role in immune function, helps produce hemoglobin, and is an energy regulator.

Found in: Soy, meat and fish, dairy and eggs, cashews, almonds, oats, lentils, beans, brown rice, legumes, and chia seeds.


This amino acid helps build and repair muscles. It also regulates blood sugar, stimulates wound healing, and helps with growth hormone production.

Found in: Cheese, soybeans, beef, pork, chicken, pumpkin, seeds, nuts, peas, tuna, seafood, beans, whey protein, and plant proteins.


Lysine is very important in the synthesis of proteins, the production of hormones and enzymes, and the absorption of calcium. It’s also involved in immune function, the production of collagen and elastin, and the production of energy.

Found in: Eggs, meat. Poultry, beans, peas, cheese, chia seeds, spirulina, parsley, avocados, almonds, cashews, and whey protein.


This essential amino acid is vital for a healthy metabolism. It also aids in tissue growth and the absorption of zinc and selenium, which are both important for the health of your liver.

Found in: Meat, fish, cheese, dairy, beans, seeds, chia seeds, brazil nuts, oats, wheat, figs, whole grain rice, beans, legumes, onions, and cacao.


Phenylalanine is vital for the neurotransmitters tyrosine, dopamine, epinephrine, and norepinephrine. It also helps proteins achieve the right structure and function properly.

Found in: Milk and dairy, meat, fish, chicken, eggs, spirulina, seaweed, pumpkin, beans, rice, avocado, almonds, peanuts, quinoa, figs, raisins, leafy greens, berries, olives, and seeds.


Structural proteins need threonine for the production of collagen and elastin, which are primary components of your skin and connective tissues. This amino acid is also important in fat metabolism and immune function.

Found in: Lean meat, cheese, nuts, seeds, lentils, watercress and spirulina, pumpkin, leafy greens, hemp seeds, chia seeds, soybeans, almonds, avocados, figs, raisins, and quinoa.


This essential amino acid maintains proper nitrogen levels and is key in the production of serotonin. You’ve probably heard about this one due to its presence in turkey and how it can make you drowsy.

| Related: The Digestive Enzymes You Need for Better Fat Digestion |

Found in: Chocolate, milk, cheese, turkey, red meat, yogurt, eggs, fish, poultry, chickpeas, almonds, sunflower seeds, pepitas, spirulina, bananas, and peanuts.


Valine stimulates muscle growth and regeneration and is needed for energy production.

Found in: Cheese, red meat, chicken, pork, nuts, beans, spinach, legumes, broccoli, seeds, chia seeds, whole grains, figs, avocado, apples, blueberries, cranberries, oranges, and apricots.

The Bottom Line

Few people realize that protein is composed of amino acids and how important these organic compounds are, not only to protein building, but to the body as a whole.

There are nine essential amino acids that find their way into the body through food consumption and sometimes through supplements. These are vital to your health on many different levels and they underscore the importance of having a well-rounded, balanced diet so you can get all of these amino acids.

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