Buildup of dead skin cells and inferioir quality deodorants often can cause discolouration of underarms.
Potatoes have natural bleaching properties. Slice a potato thinly and rub it on your underarms. Leave it on for 30 minutes and rinse without soap. Repeat twice a day for best results.
Bare Essentials Volcanic Stone is a pumice stone made from volcanic lava. Continued use over a period of time will remove your dead cells and whitens your underarms. You may also try
Xtreme Brite Brightening Gel that contains glycerine and liquorice extract helps you get rid of skin darkening and pigmentation.