CHENNAI: Testosterone is often blamed for hair loss in men, but the hormone itself is not a direct cause of baldness. Medical evidence indicates that male pattern hair loss is more closely linked to dihydrotestosterone (DHT), a potent hormone formed when testosterone is converted by the enzyme 5-alpha-reductase.
DHT acts on genetically susceptible hair follicles in the scalp. Over time, it can shorten the hair-growth phase and cause progressive follicle miniaturisation. The affected hairs become thinner and shorter before eventually disappearing in areas such as the temples, frontal hairline and crown.
However, having high testosterone does not automatically mean that a man will lose his hair. Men with normal or even relatively low testosterone levels may also develop male pattern baldness if their follicles are particularly sensitive to DHT. Conversely, some men with higher testosterone levels may retain a full head of hair.
Serum testosterone is not a reliable predictor of male pattern hair loss. The important factors are genetic susceptibility, local DHT activity and the sensitivity of androgen receptors in the scalp.
Low testosterone is also not considered a direct cause of classic male pattern baldness.
Men with low testosterone may experience general health problems, fatigue, nutritional deficiencies or illness, which can trigger diffuse shedding known as telogen effluvium. This pattern differs from the gradual recession and crown thinning typical of androgenetic alopecia.
Routine testosterone testing is therefore not usually necessary for men presenting with a typical pattern of hair loss.
Doctors may consider hormonal or other blood tests when the shedding is sudden, widespread, unusually rapid or accompanied by symptoms such as sexual dysfunction, unexplained weight changes or other signs of endocrine disease.
Treatment for male pattern hair loss generally focuses on reducing the effect of DHT on vulnerable follicles and supporting hair growth.
Medications such as finasteride and dutasteride reduce the formation of DHT, while minoxidil can help prolong the growth phase and improve the size of miniaturised follicles.
Other treatments, including microneedling, platelet-rich plasma, low-level laser therapy and hair transplantation, may be considered depending on the extent and cause of the hair loss.
Men receiving testosterone replacement therapy or using anabolic steroids should discuss hair-loss risks with a qualified doctor, particularly if they have a strong family history of baldness. Such treatment should not be started, stopped or modified solely to prevent hair loss without medical supervision.
The central message is this: male pattern baldness is primarily a matter of DHT action and genetic follicle sensitivity, not testosterone levels alone.
—The writer is a plastic and hair transplant surgeon, heading the team at Follicle Hair Clinic