How to reduce melanin from face naturally?

Avoid the sun... Melanin is produced in response to exposure to sunlight (or from tanning salon). Thus, the only way to reduce it naturally is to avoid exposure to sunlight (indoor household lights dont count). Topical bleaching cream (lustra--otc) may help, but will redarken on sun exposure. Laser treatments can be quite effective as well. Consult your doc. Good luck.