Cysteamine

Cysteamine is the chemical compound with the formula HSCH2CH2NH2. It is the simplest stable aminothiol and a degradation product of the amino acid cysteine. It is often used as the hydrochloride salt, HSCH2CH2NH3Cl (CAS#[156-57-0])

Biochemical and pharmaceutical applications
Under the trade name Cystagon, cysteamine is used in the treatment of disorders of cystine excretion. Cysteamine cleaves the disulfide bond with cysteine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria.

It is also used for treatment of radiation sickness.

Cysteamine is used in the body to form the essential biochemical Coenzyme A by combining with pantothenate and adenosine triphosphate.