Combining Glutathione and Vitamin C: How They Work Glutathione 500 mg Plus 21st Century Vitamins 21st Century Vitamins Understanding how to take supplements correctly can greatly enhance their effectiveness:, 1. Glutathione: For optimal absorption, take glutathione on an empty stomach. Pair it with vitamin C, as this Glutathione vs Vitamin C: Which is Best for Your Health? What Taking Glutathione Can Do for Your Body During Chronic Illness