What is Cysteine

Chemical Name: (2R)-2-amino-3-sulfanylpropanoic acid

Molecular Weight: 121.16

Structrual Formula:

Nitrogen Content: 11.56%

Cysteine (13,117)

  • L-Cysteine is a thiol-containing non-essential amino acid that is oxidized to form cystine
  • It is particularly abundant in skeletal and connective tissues, hair and digestive enzymes
  • The steps followed in the formation of cystine and cysteine, is from methionine to cystathionine and then to cysteine to cystine
  • Required for proper vitamin B6 utilization
  • Helpful in the healing of burns and wounds, breaking down mucus deposits in illnesses such as bronchitis as well as cystic fibrosis
  • Cysteine also assists in the supply of insulin to the pancreas, which is needed for the assimilation of sugars and starches
  • It increases the level of glutathione in the lungs, liver, kidneys and bone marrow, and this may have an anti-aging effect on the body by reducing age-spots
  • It has been shown as a detoxification agent to protect the body against damage of alcohol and cigarette smoking, and may be effective in preventing hangovers, as well as preventing liver and brain damage

Cysteine and immune system (127)

Cysteine provides resistance to the body against harmful effects by building up white blood-cell activity and it is essential for the proper functioning of the skin and helps in recovery from surgery

Cysteine and growth (136)

  • It promotes the formation of carotene which helps hair growth
  • The flexibility of the skin, as well as the texture, is influenced by cysteine as it has the ability to protect collagen, the connective tissue protein

Cysteine, smoking and alcohol (137)

  • Cysteine has been shown to protect the body against damage caused by alcohol and cigarette smoking
  • One report states that not only is it effective in preventing the side-effects of drinking, such as a hangover, but it prevents liver and brain damage as well
  • It also reduces lung damage such as emphysema, resulting from smoking

Cysteine and Cataract (138)

Cysteine and Obesity

  • Dr H. Ghadimi, Chairman of the Nutrition Committee at Nassau Country Medical Centre in New York, uses cysteine supplements to treat his patients suffering from obesity. He considers that there is a link between obesity and overproduction of insulin, and that cysteine supplements taken along with vitamin C at the end of a meal, somehow neutralise some of the excess insulin which is responsible for fat production.
  • He regards this amino acid as anti-cancer and anti-ageing, and claims that like vitamin C, cysteine protects the body from damage by oxidants

Cysteine Diabetes (6, 141)

Cysteine in Food

Cysteine can be found in whole grains, soya beans, leafy vegetables, Pistachio nuts, bananas, meat, eggs and milk

Deficiency of Cysteine (61)

In chronic diseases it appears that the formation of cysteine from methionine is prevented, resulting in a deficiency

Toxicity and symptoms of high intake (61)

People suffering from diabetes should be careful when taking supplementation, as it could inactivate insulin

Precaution (61)

  • Accumulation of free cysteine in the body tissues can lead to a rare disease known as cystinosis
  • This results in the appearance of cystine crystals in the cornea, conjuctiva; bone marrow, lymph nodes, leukocytes, and internal organs
  • Persons with diabetic tendencies should not use large supplemental doses of cysteine except under medical supervision, as it is capable of inactivating insulin by reducing certain disulphidebbrids which determine its structure
  • In order to avoid the conversion of cysteine to cystine, with possible consequences of the formation of kidney or bladder stones, an intake of three times the dose of vitamin C has been suggested to accompany the taking of cysteine supplementally


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