There are a lot of myths out there about balding men. One of them is that men with MPB are more virile and have higher levels of testosterone. This isn’t necessarily the case. Men with MPB may actually have lower circulating levels of testosterone but higher levels of the enzyme that converts testosterone to DHT. Alternately, you may simply have genes that give you hair follicles that are highly sensitive to testosterone or DHT.
There are numerous diseases that can affect the hair and scalp. Hair loss can be caused by a variety of conditions. Diseases such as alopecia areata, anemia, male/female pattern baldness, and infections of the scalp can all cause significant difficulty and loss of daily well-being. Stanford Dermatology has established a special clinic focusing on the diagnosis and treatment of these disorders of the hair.
Thyroid hormone receptors were detected in both dermal and epithelial compartments of the human pilosebaceous unit.[48] T4 and T3 decrease the apoptosis of hair follicles and T4 prolongs the duration of anagen in vitro.[49] Thyroidectomy delays initiation of anagen. Administration of thyroxine advances anagen, initiation of which is however delayed once toxic doses are given. Therefore, ratio of telogen to anagen hairs is increased in hypothyroidism as well as hyperthyroidism.[50] Thus, the hair follicles are affected in thyroid disorders, and madarosis is caused due to disturbances in hair cell kinetics. Hypothyroidism is associated with generalized hair loss probably due to coarse, dull, and brittle hair with reduced diameter.[51] The eyebrows and eyelashes may also be lost. Loss of lateral one-third of eyebrows known as Hertoghe sign[38] is a characteristic sign of hypothyroidism.[52] Some people also refer to it as Queen Anne's sign,[53] after Anne of Denmark whose portrait with shortened eyebrows has been interpreted by some as indicative of the presence of goiter, even though such a fact has not been proved by any known sources of information. Madarosis may even be the presenting sign in hyperthyroidism.[21] In hyperthyroidism, there is thinning with breaking off and shortening of hair.[54] Madarosis can also occur in hypopituitarism, hypoparathyroidism,[21] and hyperparathyroidism.[55]