 Cystamine is an unstable liquid and is generally handled as the dihydrochloride salt, C4H12N2S2·2HCl, which is stable to 203-214 °C at which point it decomposes.Cystamine is toxic if swallowed or inhaled and potentially harmful by contact.Cystamine is an organic disulfide which is formed when Cystine is heated as a result of decarboxylation.