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What Is Cysteine?

Cysteine is mostly a non-essential amino acid. Non-essential means that the body can synthesize the acid itself. But in some cases, cysteine can be essential for infants, the elderly, and some people with certain metabolic diseases, making it a conditionally essential amino acid.

For the body to be able to synthesize cysteine, is it crucial that there is a sufficient quantity of the amino acid methionine. Cysteine has the same structure as the amino acid serine.

Benefits Of Cysteine

Cysteine is a conditionally essential sulfur-containing amino acid. (source đź——)

Cysteine is found in beta-keratin, an important component of skin, hair, and nails. (source đź——)

You can find other benefits of cysteine in Cysteine: 5 Research-Backed Benefits .

Cysteine In The Body

The human body uses cysteine to produce the antioxidant glutathione, as well as the amino acid taurine. The body can also convert cysteine into glucose for a source of energy. (source đź——)

Cysteine In Food

By eating enough protein in your diet, you get all of the cysteine and all other important amino acids you need. (source đź——)

If you are interested in a list of foods where you can find this nutrient. Go to our nutrition tool and check out cysteine.

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Sara Niemelä

co-founder Care Omnia, Head Content Creator


I’m a wife and a mother of three. I enjoy the outdoors, cooking, and spending time with my family. Nutrition is my passion. I have spent thousands upon thousands of hours reading, analyzing, categorizing and comparing research studies. Nutrition is the foundation you build a healthy and fulfilling life upon!