What Are Nonessential Amino Acids?

The quest to eat a healthy diet can feel overwhelming. But some of what your body needs is already found within, including nonessential amino acids. Amino acids are what proteins are made up of — and there are different types, including nonessential and essential amino acids. In this explainer, we take a closer look at the non-essential type of amino acids and how your body uses them.

Amino acids are the components that make up protein, which your body needs to function. When people talk about amino acids, they usually mean a subset of 20 or so that are used by the human body. Most of these are proteinogenic amino acids, which are used to create proteins.

While the average person probably thinks of protein in relation to muscle-building, in your body proteins actually serve a wide variety of functions, including helping the immune system, providing structural support for cells and carrying small molecules throughout the body.

Nonessential amino acids are the amino acids that can be produced by the human body. There are 11 such amino acids.

Conditionally essential amino acids are usually not essential for humans, except during periods of stress or illness. These amino acids include arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline and serine. The average person doesn't need to worry about conditionally essential amino acids when they are healthy.

Essential amino acids cannot be synthesized by the human body and must be consumed in food, while nonessential amino acids can be created by the human body. There are nine essential amino acids.

The 11 nonessential amino acids are:

Despite being called "nonessential," these amino acids are still critical for various functions in the human body. You just don't need to get these from food.

Each amino acid has a different function, since they each build different proteins, which have their own diverse roles in keeping different biological processes going. For example, cysteine helps to create collagen and is important for skin elasticity, while it may also play a role in hair growth. Meanwhile, tyrosine is critical for many aspects of brain function, and helps to make a variety of substances in your body, including neurochemicals like dopamine and adrenaline.

Amino acids are critical for every person. If someone does not have an adequate intake of protein or amino acids, it can cause serious and long-lasting problems, including skin or hair loss, hormone imbalance, lesions and stunted growth. These symptoms are quite severe and unlikely to be experienced by individuals in developed nations. That's because they are usually a result of not having enough food to meet basic energy needs, rather than eating the wrong things. As long as you’re eating a variety of mostly plant-rich foods, you should be able to get the nutrition that you need.

There is no single process your body uses to make nonessential amino acids. Instead, your body uses a plethora of metabolic pathways and base chemicals to create amino acids.

Since amino acids come from protein, you can find amino acids in protein sources, both animal-based and plant-based. It's not necessary to worry about "complete" proteins. The notion that some proteins are better than others because they are "complete" and contain nine essential amino acids is a myth. Plants do contain all nine essential amino acids, some just contain less than others. It's not necessary to eat proteins that contain all nine in certain amounts. Eating a varied plant-rich diet will ensure you get enough of these vital nutrients.

There's not enough evidence to suggest that amino acid supplements are more effective than simply eating a variety of foods rich in amino acids.

A growing number of exercise professionals recommend what are called BCAA supplements, which contain three of the essential amino acids — leucine, isoleucine and valine. Despite the claims that these can improve athletic performance, stimulate muscle recovery and reduce muscle soreness, studies show the human body absorbs nutrients from food more efficiently than pills or supplements anyway.

Dietary supplements are also not regulated by the Food and Drug Administration (FDA) for safety and effectiveness. And because amino acid supplements can sometimes interact with medications, seek professional medical advice before taking this or any other supplement.

Amino acids come from any protein source, including plant-based proteins. As long as you are eating a reasonably healthy diet you will be getting enough essential amino acids from your food, whether your diet includes animal products or not — and for nonessential amino acids, your body does all the work for you.

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Björn Jóhann Ólafsson is an Icelandic-American writer who examines the psychology of eating animals, the environmental footprint of the meat industry, and the plant-based meat industry. He lives in Spain with his two lovebirds.