7. Hair Loss
Both hypothyroidism and hyperthyroidism can be detrimental to hair quality and growth. When too little hormone is produced by the thyroid, increased numbers of hair follicles enter into “resting mode,” leading to hair loss and dry, brittle strands. This hair loss is not restricted to the scalp alone but also occurs on other parts of the body, including the limbs, underarms, and even eyebrows. Hyperthyroidism, on the other hand, tends to affect only the scalp, but hair loss there is often more severe and noticeable than in hypothyroidism. Fortunately, full hair growth can be restored with appropriate treatment.