Amino Acids Explained

Table of Contents

Amino acids can be described as organic molecules that are the building blocks for proteins. Proteins are essential for a wide variety of functions in the body from neurotransmitters, DNA synthesis, and metabolic functions, to cell structure, transport in and out of cells, hormone production and regulation, antibodies in our immune system, and even responding to stimuli.

Stripped down to the very basics, proteins are long chains of molecules that are essential to life. And without their amino acid building blocks, proteins can’t form and perform as needed.

When you look closely at proteins, they’re made up of amino acids. There are hundreds of naturally-occurring amino acids, but the human body requires only about 20 of them. There are some that the body can make on its own, these are called non-essential amino acids. And there are nine amino acids that the body can’t make. These are called essential amino acids and it’s very important that we get them through our diet or with supplementation.

The structure of amino acids

All amino acids consist of carbon, hydrogen, nitrogen, and oxygen. These are assembled into molecules. When looking at the structure of an amino acid, you’ll note a basic amino group (1), and an acidic carboxyl group (2). These are joined together by a carbon bond and there is an organic side-chain that’s also known as the R-group (3), which is unique to every type of amino acid.

Amino acids explained through a diagram of amino, carboxyl and R groups

Depending on how the amino acid is structured, it is classified into alpha, beta, gamma, or delta groups and further classified as hydrophobic, basic, acidic, or aromatic, to name some examples. But we’re not going to go into organic chemistry here. If you want to know about this in more detail, here’s a great explainer video:

Where do amino acids come from?

Amino acids generally come from protein-rich food sources – remember, proteins are built up of amino acid chains. This means you can get a wide variety of amino acids from fish, meat, dairy, and eggs; or from protein-rich plants such as tofu, lentils, beans, soybeans, and nutritional yeasts, to give some examples.

In fact, certain plant-based proteins from foods like edamame, tofu, and soy contain all nine essential amino acids making them a “complete” protein source. Certain combinations of plant-based foods like whole grains combined with peanut butter, beans combined with seeds or nuts, and even lentils combined with rice provide all nine essential amino acids with no trace of animal products.

What are the nine essential amino acids?

There are nine amino acids that the body can’t synthesize. What are they and what do they do? Here’s a list and brief explainer. But for more detail, click on each one to discover lots more.

Histidine – If you think it sounds like histamine, you’re right. This amino acid is needed to produce histamine, which is a neurotransmitter linked to immune system responses. It’s also needed for your circadian cycle, keeping your nerves healthy, digestion, and even sexual function.
Isoleucine – found in large concentrations in muscle tissue, this amino acid is responsible for muscle metabolism, immune system function, energy regulation, and the production of hemoglobin in the blood.
Leucine – this amino acid is needed for growth, making proteins, and repairing muscles and wounds. It’s also important for regulating blood sugar and producing certain hormones.
Lysine – this is needed for calcium absorption, making certain hormones and enzymes, building proteins, and energy. Like threonine, it’s needed for elastin and collagen production and a healthy immune system.
Methionine – when it comes to metabolism and detoxification, this amino acid has a large role to play. It’s also needed for the absorption of minerals like selenium and zinc.
Phenylalanine – this is used primarily for neurotransmitters like dopamine, epinephrine, and norepinephrine.
Threonine – this is necessary for connective tissue and structural proteins in our body and skin like collagen and elastin. It’s also needed for fat metabolism and a healthy immune system.
Tryptophan – this is important in the synthesis of neurotransmitters that regulate sleep, mood, and appetite.
Valine – this is necessary for muscle growth and repair, as well as giving us energy

Amino acid deficiencies

In the modern world, it’s quite rare to have an amino acid deficiency because of the variety and quantity of foods available to us all year round. However, it’s clear from the above list of functions that amino acids play incredibly important roles in the body, and whether it’s because of stress, exertion, or illness, some people may benefit from increasing the amount of amino acids they consume through food, or consider introducing a supplement to help with problems associated with mood, sleep, recovery or wound healing, performance, or even improving immune function and energy levels.

To learn more about each of the essential amino acids, see our list below. You’ll discover what each one does, where you can get amino acids in your diet, what products you can buy for amino acid supplementation, and even how you can mix amino acids to meet your particular goals.

List of amino acids

Essential Amino Acids	Non-essential Amino Acids
Histidine	Alanine
Isoleucine	Arginine
Leucine	Asparagine
Lysine	Aspartic acid
Methionine	Cysteine
Phenylalanine	Glutamine
Threonine	Glutamic Acid
Tryptophan	Glycine
Valine	Proline
	Serine
	Tyrosine

Your health and protein consumption

Like any modifications to your diet or introducing supplements, it’s important to consult with your primary healthcare provider before you start. While there are many benefits to be gained from a diet rich in amino acids, there are health problems associated with consuming too much protein. These include dizziness, fatigue, headaches, constipation, and bad breath, in the short term, and potentially even colon cancer in the longer term.