Other name(s):

a-amino-b-thiolpropionic acid

Unsubstantiated claims

Please note that this section reports on claims that have NOT yet been substantiated through scientific studies.

Cysteine may be beneficial in treating arthritis (L-cysteine), hardening of the arteries, and lung diseases such as bronchitis, emphysema, and tuberculosis. It may help protect the lungs from cigarette smoke.

Cysteine is believed to help protect the liver from alcohol, prevent hangovers, and prevent damage to brain cells from alcohol.

Cysteine is believed to play a role in the normal growth rate of hair. Cysteine may possibly help reduce the effects of aging on the skin, assist in healing after surgery or burns, and help protect the skin from radiation injury.

Cysteine is also claimed to help burn fat and increase muscle mass.

Recommended intake

Amino acids (AAs) are available as individual AAs or in proprietary AA combinations, as well as part of multi-vitamin formulas, proteins, and food supplements. The forms include tablets, fluids, and powders. However, adequate protein in the diet should provide a sufficient source of all amino acids.

There are no conditions that increase the nutritional requirements for cysteine.

Side effects, toxicity, and interactions

The use of a single amino acid supplement may lead to negative nitrogen balance, decreasing the metabolic efficiency and increasing the workload of the kidneys. In children, taking single amino acid supplements may also harmfully affect growth parameters.

Always avoid taking individual amino acids in high dosage for prolonged periods.

Women who are pregnant or breastfeeding should not use cysteine supplements.

Other conditions in which this nutrient should not be used include cystinuria (a rare genetic disorder resulting in the formation of cystine kidney stones) and diabetes, as cysteine may interfere with insulin function.

Additional information

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