Abstract In order to evaluate the influence of an amino acid conjugation (Sar, Ser, Phe, Pro, Thz) on S-acetylcysteamine, cystamine, N-(amino acid)-S-acetylcysteamine (14–18) and N, N′-bis (amino acid) cystamine (24–28) derivatives have been synthesized and evaluated as potential radioprotectors. Their toxicity and radioprotective activity, as the dose reduction factor (DRF) have been determined (in vivo; ip) and compared with cysteamine and ...