What is the Origin of Thyroid and Hair?

This clinical relationship is well-documented in endocrinology and dermatology, where hair changes are a classic, though often subtle, sign of thyroid dysfunction. The hair follicle is recognized as a target organ for thyroid hormone action.

What is the Mechanism of Thyroid and Hair?

Thyroid hormones regulate the basal metabolic rate and cellular proliferation throughout the body, including the highly active cells of the hair follicle. T3 acts on nuclear receptors within the hair follicle cells to modulate gene expression critical for growth and differentiation. In hypothyroidism, the slowed metabolism prematurely terminates the anagen (growth) phase, leading to increased telogen (resting) hairs and subsequent shedding. Conversely, in hyperthyroidism, the accelerated metabolism can also disrupt the cycle, often resulting in fine, soft hair texture and increased

Thyroid and Hair ∞ Area

Thyroid and Hair

Meaning

The connection between Thyroid and Hair refers to the direct and critical influence of thyroid hormones, specifically triiodothyronine (T3) and thyroxine (T4), on the health and growth cycle of the hair follicle. Both hyperthyroidism and hypothyroidism can disrupt the hair cycle, leading to diffuse hair thinning or loss. Maintaining euthyroid status, meaning optimal levels of circulating thyroid hormones, is therefore essential for supporting the proliferative activity and structural integrity of the hair matrix.