I feel for your daughter. My mother was hypothyroid, and so I was tested several times in my teen years. They always said I was borderline and should "get tested again in a year". My TSH levels stayed around 4 or 5 for a long time and no one treated me. They did, however, treat my symptoms with Zoloft, Wellbutrin, Prozac, Paxil... (not all at the same time :) I was always a little heavy and suffered from bad mood swings. I'm being treated for real now, and I am fine and well adjusted... bla bla... But being overweight even though you go to the gym and eat what your friends do is really traumatic for a teenage girl. I never felt normal.
I wonder why they won't treat her? Is it because of her age? Are there endos that specialize in teenagers? It must be so frustrating for you!
Any TSH over a 2.5 should be followed carefully.
What is her TSH?
If at least 1 result was over the limit, she should more than likely be treated.
Have they tested her for thyroid antibodies? Is there a family history?
Have you seen an endo?