There are a few potential explanations for why thyroid medicine might cause hair loss. One possibility is that the medication causes your body to produce less of the hormone estrogen, which can in turn lead to hair loss. Another possibility is that the medication stimulates your thyroid gland too much, which can also lead to hair loss. Finally, it’s also possible that the medication itself damages hair follicles, leading to hair loss.
If you’re experiencing hair loss after starting thyroid medication, be sure to speak with your doctor about whether there might be an alternative medication that would work better for you. There are a number of different thyroid medications available, and each person may respond differently to different medications. There might also be other ways to help manage