Loss of body hair
A thinning or loss of hair on the body — such as underarm, pubic or facial hair — as distinct from scalp hair loss. It can be a sign of low sex hormones or an underactive pituitary or thyroid, so a gradual, unexplained loss of body hair is worth checking.
What it means
Loss of body hair means a reduction in the hair on the body — underarm, pubic, chest or facial hair — rather than the more familiar loss of hair from the scalp. Body and sexual hair depends heavily on the sex hormones, particularly androgens (male-type hormones present in both sexes), so a loss of this hair often reflects a fall in those hormones. Causes therefore include low testosterone in men (hypogonadism), a fall in adrenal androgens, and, importantly, an underactive pituitary gland (hypopituitarism), where reduced pituitary signals lower both the sex-gland and adrenal hormones — loss of body hair can be one of its quieter clues. An underactive thyroid also thins hair, including body hair and the outer eyebrows. Other causes are certain skin and autoimmune conditions, some medications, poor nutrition, and normal ageing, where body hair naturally thins. Because the sexual and body hair is a visible readout of hormone status, a gradual, unexplained loss — especially alongside low libido, fatigue or other hormonal symptoms — can be a useful pointer to a treatable hormonal cause.
Common causes
- Low testosterone (hypogonadism) — in men, thinning of body, facial and pubic hair.
- Hypopituitarism — reduced sex-gland and adrenal hormones; body hair loss can be a clue.
- Underactive thyroid — thinning hair, including the outer eyebrows.
- Normal ageing — body hair naturally thins over time.
- Skin or autoimmune conditions — such as alopecia affecting body hair.
- Some medications and poor nutrition.
Lab work-up approach
When loss of body hair is gradual and unexplained, especially with other hormonal symptoms, blood tests target the likely causes: testosterone (and LH, FSH) for low sex hormones, thyroid function (TSH and free T4) for an underactive thyroid, and, if a pituitary cause is suspected, the pituitary hormones and cortisol read together. The pattern — low target-gland hormones with low or normal pituitary signals — is what points to the pituitary. A skin examination assesses local causes. Mediora.AI can surface a low-testosterone or thyroid pattern, or the pituitary picture, from your results to help identify a treatable cause; the interpretation belongs with your doctor.
Tests Mediora.AI can interpret
Related conditions
Panels to consider
When to see a doctor
A little thinning of body hair with age is normal and needs no action. See a doctor if loss of body hair is noticeable, progressive or unexplained, and especially if it comes with other symptoms — low libido, erectile dysfunction or loss of periods, fatigue, cold intolerance, or low blood pressure — which together can point to a hormonal cause such as low testosterone, an underactive thyroid, or an underactive pituitary, all of which are treatable. Loss of body hair after a pituitary problem, head injury or radiotherapy also deserves assessment. Mediora.AI helps flag the sex-hormone, thyroid and pituitary contributors so the pattern is visible; progressive or unexplained loss of body hair is assessed by your doctor.