Hi Greetings. Reversing white hair to black is indeed among the tough results to show to a patient since this is a multifactorial problem. Since in most it's genetically mediated, it's tough to reverse or treat. It is also possibly mediated by stress and environmental factors. However there are certain peptides and newer molecules application of which may be worth a trial. It's also important to rule out hormonal irregularities and nutritional deficiencies. Increase intake of oral anti oxidants. Meet a qualified dermatologist near you for further advise. Hope this helps Caution: Make sure you see a qualified MD / DNB/ DVD dermatologist for all your skin and hair issues. Don’t be lured in by quacks. Know your treating doctor/ discourage quackery! Warm regards, Dr Govind Suresh Mittal. Bengaluru