Wizard of Vitamins

Cysteine Vitamin

What is Cysteine?

Cysteine is a nonessential amino acid (protein building block), meaning that cysteine can be made in the human body. Cysteine is one of the few amino acids that contains sulfur. This allows cysteine to bond in a special way and maintain the structure of proteins in the body. Cysteine is a component of the antioxidantglutathione. The body also uses cysteine to produce taurine, another amino acid.

Cysteine in Diets

The body can synthesize cysteine from methionine and other building blocks. Cysteine, the amino acid from which NAC is derived, is found in most high-protein foods.

Cysteine Medicinal Treatments

Known Consequences of Cysteine Deficiency

According to several studies, blood levels of cysteine and glutathione are low in people infected with HIV. Cysteine has a role in the proper function of the immune system, so a deficiency of this amino acid may either contribute to, or result from, immune suppression associated with HIV.

Cysteine Recommended Dosages

Most people do not need to supplement with cysteine. Almost nothing is known about appropriate supplemental levels, in part because almost all clinical research has been done with N-acetyl cysteine and not cysteine itself.

Cysteine Side Effects

No consistent adverse effects of NAC have been reported in humans. One small study found that daily amounts of 1.2 grams or more could lead to oxidative damage. Extremely large amounts of cysteine, the amino acid NAC is derived from, may be toxic to nerve cells in rats. Adequate amounts of methionine are needed in the diet, as the precursor to cysteine, to prevent cysteine deficiency. At the time of writing, there were no well-known drug interactions with cysteine.