Re: Dry, brittle hair
It's a mistake to assume that every symptom that can be associated with hypoT is caused by hypoT. If you had no other signs of it then, like smaller than average stature, learning disabilities, lethargy, impaired immunity, constipation, etc... then you probably were not hypothyroid at that time and your dry hair was caused by something else.
HypoT can slow down almost every body system. Not every hypoT person experiences all of the possible symptoms, though. Oil glands can produce sluggishly, hence dry hair and skin. Hair falls out excessively because the hair growth cycle is interrupted, making the older hairs fall out sooner while the new ones are slower to replace them.
Interesting to note... There is credible evidence that having only one gray hair before the age of 30 means that person is predisposed to low thyroid later in life. My best friend found a gray hair among my auburn ones when we were only in 4th grade.