Abstract: Low-toxicity, highly-bioavailable, pharmaceutical antioxidant compositions for preferred oral administration to mammals are provided which have at least one amino acid-based compound of the general formula (I): A—N(Z)—CH(R1)C(O)—Q  (I) wherein A is represented by the formula: XO—[C(R2)2]n— wherein n is an integer of from 1 to about 3, X is selected from the group consisting of a hydrogen atom, an acyl group and a halogenated acyl group and each R2 is independently selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to about 3 carbon atoms, a hydroxyalkyl group having from 1 to about 3 carbon atoms, and CH2OX; Z is selected from the group consisting of a hydrogen atom, an alkyl group of from 1 to about 3 carbon atoms, and A; R1 is an amino acid side chain group or an amino acid side chain group which forms with R2 a single heterocyclic structure having a total of from 5 to 7 atoms in the ring; and wherein Q is a substituent s