glutathione reductase with nadph NOX-like ROS production by The NADPH Link between the
Description
This will depend on your goals and current health

2002;12(9):117R125R

But success here depends entirely on the causes of your greying, and how much damage/depletion has occurred to hair follicle melanocyte stem cells
A number of assays are available to measure OS including chemiluminescence for ROS, total antioxidant capacity for antioxidants, and the malondialdehyde assay for post-hoc damage from lipid peroxidation [74, 75, 76]
