But if you notice that your eyebrows have thinned, and in particular, if the outer edge of the eyebrows have thinned — or even disappeared — that’s a sign that it’s time to have your thyroid checked.
This loss of hair in the outer edge of the brows is one of the very unique signs that point specifically to an underactive thyroid – known as hypothyroidism.
But any old thyroid check will not do. It’s not enough to just have the standard Thyroid Stimulating Hormone (TSH) test. At minimum, you will want bloodwork to check TSH, Free Thyroxine (Free T4), Free Triiodothyronine (Free T3), Thyroid Peroxidase Antibodies (TPO), and Ferritin levels.
Results need to be interpreted by an integrative physician or practitioner who is knowledgeable about hormone balance. If you are clinically or even subclinically hypothyroid — or you have evidence of Hashimoto’s disease, which often picked up by elevated TPO antibodies — you may have this eyebrow thinning or eyebrow loss as a symptom.
Once you are properly diagnosed, treated, and optimized, it’s likely that your eyebrows will slowly grow back in. (But be patient — it can take months to see results!)