My younger daughter (16) says her hair has become noticeably thinner
in recent years--not in the sense of balding, but in the sense of
losing "body." Since she was 12 or so, she has straightened her hair
about twice a week with a "flat-iron" type appliance, and she wonders
about a few related questions: (1) Could this have caused the thinning
of texture--or could that thinning be a possible normal change, after
childhood? (2) Should she stop doing the straightening? (3) If she has
harmed her hair, what should she do to make it thicker again?

I mentioned "younger" daughter because her older sister, 21, also used
that straightening appliance but has not noticed thinning in her own hair.

Only a very partial response posted as a comment. 

Disclaimer: Comments provided on Google Answers are general
information, and are not intended to substitute for informed
professional medical advice.

Other than common sense answers - see below - there is very little
information on the web concerning this topic.

Your daughter should mention it to her primary care physician the next
time she sees him in any event.


1) Could this have caused the thinning of texture--

Yes.  In the absence of other contributing factors, (does she also dye
her hair or use caustic chemicals to bleach, etc.), the flat-iron type
device should be considered as a possible contributing factor.


2) Should she stop doing the straightening? 


Yes, or use a less damaging method.  This will allow you to determine
whether the thinner hair was due to the straightening - or possibly
due to an underlying medical problem.


2) or could that thinning be a possible normal change, after
childhood?

3) If she has harmed her hair, what should she do to make it thicker
again?


Let it heal naturally over time.  

Second disclaimer:  If after a few months it has not recovered,
schedule an appointment with a doctor as it may be a symptom of some
other medical problem.  And of course if there are other medical
problems/symptoms your daughter presents, you should not wait, but
schedule an immediate medical appointment.  And she should mention
this problem to her primary care physician during her annual check up
in any event.


------------------------------------
A commercial web site - with well written information.  
Read the information, don't buy the products.


Skin Biology Aging Reversal  
Chapter 10. Hair Biology, Hair Care, and Loss 

http://www.skinbiology.com/hairbiology,care&loss.html

Alternatively, intense heat can also reset hair bonds, allowing curly
hair to be straightened by ironing with a regular electric iron and an
ironing board or flat surface covered with a smooth towel. This
technique was very popular in the "long-hair" times of the 1960's and
70's. It is best to have someone else iron your hair straight to avoid
the danger of burns.

        Conair makes a product that helps straighten hair without the
dangers of burns to the skin or hair damage. It is called Straight
Styles, #SS6 that produces steam which straightens the hair as you
comb through the hair. It is sold in Sears and Service Merchandise
stores or can be ordered directly from Conair $33.99 plus shipping and
handling by calling Conair's number at 1-800-326-6247, Monday -
Friday, 8:30 am - 4:30 pm EST.

To amalik-ga
Many thanks for this helpful and informative posting. I'm sure my
daughter will follow your suggestions (I'm going to e-mail the posting
to her, and we'll talk about it, I'm sure.) That was a lot of valuable
information....And written with a precision that suggests you're a
doctor. In any case, thoughtful and much appreciated.
bbb-ga