BrittleD-I have been on forteo now for about a year. I have had hair loss and eyebrow thinning, but I believe this is due to being hypothyroid and synthroid the drug I am taking for being hypothyroid. Have you been tested for low thyroid? My hair really started falling out when I started the thyroid treatment which was about 6 weeks before starting the forteo. Doctors have told me whenever your metabolism changes while on the thyroid med, that is whether your tsh goes up or down , the movement can result in hair loss.And, this has happened to me. So, in the end I am thinking that for me it doesn't have to do with the forteo but the thyroid situation.