Disclosed herein are compounds and methods of using such compounds for treating or suppressing oxidative stress disorders, including mitochondrial disorders, impaired energy processing disorders, neurodegenerative diseases and diseases of aging, or for modulating one or more energy biomarkers, normalizing one or more energy biomarkers, or enhancing one or more energy biomarkers, wherein the compound is a compound of Formula I or Formula II: wherein: R1 and R2 are independently hydrogen, (C1-C6)alkyl or —O(C1-C6)alkyl; or R1 and R2 together represent —CH═CH—CH═CH—; R3 is (C1-C6)alkyl; X is —CH═CH— or —C≡C—; m is 1-10; n is 1-5; k is 1-3, with the proviso that when k is an integer of 2 or 3, n is independently 1-5 in each occurrence of the —X—(CH2)n— group; Y is —OR4, —CN, —C(═O)OR5, —C(═O)R5, or —C(═O)N(R6)2; R4 and R5 are independently selected from the group consisting of hydrogen, —(C1-C6)alkyl, —(C1-C6)haloalkyl, —C(═O)—(C1-C6)alkyl, —C(═O)—(C1-C6)haloalkyl, —C(═O)—NH(C1-C6)alkyl, —C(═O)—N((C1-C6)alkyl)2, —C(═O)—NH2, and phenyl, wherein the phenyl group may optionally be substituted with a substituent selected from the group consisting of —(C1-C6)alkyl, —O—(C1-C6)alkyl, —(C1-C6)haloalkyl, and halo; each R6 is independently hydrogen or —(C1-C6)alkyl; and M is —H, —C(O)—R7 or —C(O)O—R7, wherein R7 is —(C1-C6)alkyl or phenyl; or a stereoisomer, mixture of stereoisomers, pharmaceutically acceptable salt, crystalline form, non-crystalline form, hydrate or solvate thereof.