Thyroid disorders and hair loss

The thyroid controls the body's metabolism, and the hair follicles are sensitive to disturbances. Both an underactive (hypothyroidism) and an overactive (hyperthyroidism) thyroid can therefore cause hair loss, usually a diffuse thinning across the whole head rather than a clear pattern. A classic extra sign is that the outer third of the eyebrows thins out.

This type of hair loss resembles telogen effluvium: a large proportion of follicles enter the resting phase, and the shedding is often noticed only a few months after the imbalance began. Because hair grows slowly, it can also take a while before you see improvement after the thyroid has been treated.

The good news is that thyroid-related hair loss is almost always reversible. Once the thyroid values (TSH, T4, sometimes antibodies) have been investigated and normalised with the right medication, the hair usually returns to normal growth. That is why the first step is always a medical investigation, not a hair treatment.

At Hair TP Clinic we often see patients who believe they have hereditary hair loss when an untreated thyroid is the real cause. At a free consultation we do a trichoscope assessment and recommend blood tests if the pattern points to an underlying thyroid disorder. PRP can be used as support to stimulate the follicles during recovery, but it never replaces treating the thyroid itself.