For as long as I can remember, I’ve always had a thick shock of wavy brown hair. Through the years, I couldn’t help but wonder how long my hair will last before it thins and eventually leaves my scalp entirely. My father is almost entirely bald, and I certainly wouldn’t be able to rock that look as well when I get to that stage of life. Thus, I’m looking to examine what factors in genetics and natural human balding patterns may play into when I start losing/lose my hair, because it will likely be an inevitable part of my development into adulthood.
Let me start out by explaining the hair growth cycle for the average person. Generally, each hair on one’s head grows for 2 to 6 years before falling out if left uncut. The fallen hair is replaced by a new strand of hair, from the same follicle. Eventually, the hair producing follicles become smaller, leading to a decrease in thickness and length of hairs, before ceasing to grow any strands. The follicles begin to close up due to a genetic sensitivity towards Dihydrotestosterone (DHT).
The most common balding pattern among men is aptly named Male Pattern Baldness (MPB) (Androgenetic alopecia). Generally, MPB is found in 20% of Caucasian men (like myself) aged 20 years old, and follows the same rule as men age: 30% at age 30, etc. Baldness is hugely influenced by genetics. A case study showed that between 476 monozygotic and 408 dizygotic male twin pairs with ages ranging from 25 to 36 years, there is a hereditability of 0.81 (95% Confidence Interval, 0.77 – 0.85) concerning MPB. This study shows that twins are more likely to have similar hair loss results, likely resulting in genetic similarities from their parents.
This graphic expresses the Hamilton-Norwood standards of classification, giving a pictoral explanation as to how to classify baldness. The higher the Roman Numeral denotes the higher severity of the baldness. In a study of 2029 males aged 25-36, the frequencies of each type of baldness are as follows:
No hair loss: 61.2%, I: 6.5%, II: 14.2%, IIa: 2.9%, III: 4.3%, IIIa: 1.5%, IIIv: 3.8, IV: 1.6%, IVa: 1.0%, V: 0.8%, Va: 1.1%, VI: 0.4%, and VII: 0.5%.
Earlier I noted that my father is bald; he fits into the VI category of Hamilton-Norwood standards. A study was done on 410 men experiencing premature loss of hair. This case determined that 236 of the men had irrefutable genetic evidence that their fathers’ genes had played a part in determining the baldness of the sons.
It is still unknown exactly what percentage of hair loss can be attributed to genetics and ethnicity because every man has a different hair loss experience. However, there is evidence to provide the assumption that I myself may go through balding at some time in my 20’s, due to both genetic predispositions and natural male balding patterns.