A dietary supplement of mitochondrial nutrients is designed for relieving stress, preventing and improving stress-related disorders, such as chronic fatigue syndrome, diabetes, age-associated cognitive dysfunction and diseases (Parkinson's and Alzheimer's disease). The supplement composition has the following nutrients: B vitamins (cyanocobalamin 2-1,000 ug, thiamin 1-1,000 mg, niacin 15-2,000 mg, pyridoxine 1-1,000 mg, Pantothenate 5-150 mg, folic acid 400-40,000 ug), alpha-tocopherol 10-800 mg, ascorbic acid 50-10,000 mg, calcium 20-2,000 mg, vitamin A 200-10,000 ug, alpha-lipoic acid 100-1,000 mg, N-acetyl cysteine 100-3,000 mg, L-carnosine 100-9,000 mg, tyrosine 100-9,000 mg, vanillin 10-100 mg, phosphatidylserine 10-800 mg, resveratrol 10-50 mg, dehydroepiandrosterone 1-50 mg, and melatonin 0.1-3 mg, all of which have been individually used experimentally or clinically for relieving stress, preventing and treating age- and stress-related disorders and diseases but no combination of these compounds has been used. Many embodiments also contain at least one adjunct ingredient such as coenzyme Q 10-200 mg, acetyl-L-carnitine 100-2,000 mg, choline 50-1,000 mg, and creatine 100-2,000 mg.