Question: What are the best ways to optimize glutathione status for someone who has a G6PD deficiency?   Riboflavin was shown to be of benefit for normalizing oxidative stress in people who have glucose 6-phosphate dehydrogenase deficiency.   So for people who don't know what this is G6PD is, glucose 6-phosphate dehydrogenase is an enzyme that you use to take energy from glucose specifically, you can't take it from anything else, and you use it to recycle glutathione which is a master antioxidant of the cell.    You also need this to support the recycling of vitamin K and folate and you need this for synthesis of neurotransmitters among other things.   But the big problem with G6PD deficiency is that you can have a lot of things go sideways when you can’t use this pathway. Red blood cells become more vulnerable to hemolysis and that is a result of oxidative stress from poor glutathione recycling in the red blood cell.    One of the adaptive responses to having G6PD deficiency is the glutathione reductase enzyme -- which is the enzyme that uses riboflavin and niacin to recycle glutathione with the energy taken from G6PD.    That enzyme -- glutathione reductase -- it develops a voracious appetite for riboflavin that makes all the riboflavin that won't go anywhere else, get sucked up into that enzyme. So basically you become very dependent on riboflavin support of glutathione reductase because you have lost G6PD, the enzyme that's involved in passing the energy on to riboflavin in glutathione reductase.   There's probably no harm to starting at 400 milligrams of riboflavin a day, but if you feel like you want to be more cautious about it, I'd start at 5 or 10 milligrams a day, test the effect on glutathione status.   You know in this case I think you want to look at erythrocyte glutathione status, I don't usually recommend that test, but it might be a more relevant test specifically for this condition.    What I would usually recommend for glutathione status would be plasma levels of glutathione. I also think LabCorp does whole blood glutathione.  This Q&A can also be found as part of a much longer episode, here: https://chrismasterjohnphd.com/podcast/2019/02/24/ask-anything-nutrition-feb-17-2019/   If you would like to be part of the next live Ask Me Anything About Nutrition, sign up for the CMJ Masterpass, which includes access to these live Zoom sessions, premium features on all my content, and hundreds of dollars of exclusive discounts. You can sign up with a 10% lifetime discount here: https://chrismasterjohnphd.com/q&a