hello i am a 27 year old male.. i have had dry hair since the age of about 13 ...recently i have been doing research to find a internal cause..i was told that a Physiological causes = the sebaceous glands do not produce enough sebum...and that The secretions of the sebaceous glands are controlled by hormones circulating through the blood vessels in the scalp. Hormonal shock periods, such as puberty, adolescence, after childbirth and the menopause may greatly affect the condition and appearance of the hair. do you know anything about this..also is there anyway to correct this problem internaly..i have had several thyroid test tha came up negative...do you have any suggestions on where to find a expert in this area? can one get tested for this problem? do you know what i can do to correct the problem? thank you!