Is it bad for your health to use a lot of shampoo like half a handful sometimes it's because my hair is so dry it absorbs it quickly.

Yes: Soaps can cause dryness to the hair, some dermatologist only recommend washing the hair once a week. The natural oils of the hair are stripped when you wash too often. Hair will remain healthy without much upkeep. If you get dry hair or flakey hair you likely have dandruff and should use head and shoulders or neutrogena t-sal/t-gel. www.bmednyc.com