Next to each hair is a sebaceous gland which secrete sebum which lubricates the hair and provides each hair with an element of protection. If the sebaceous glands are overactive greasy or oily hair will result. If the glands are underactive dry hair may result including breakage.
Daily Hair Tip
A humectant hair product attracts moisture to the hair while an anti-humectant repels moisture. Use a humectant to combat static electricity and an anti-humectant to deal with humidity.