Male pattern baldness, scientifically known as androgenic alopecia, is a common condition that affects millions of men and women. It is characterized by the shrinkage of hair follicles, which leads to the thinning and eventual loss of hair. This process is influenced by hormones and specific genes. The National Institutes of Health (NIH) estimates that around 50 million men and 30 million women in the United States alone experience male pattern baldness.
Testosterone exists in various forms within the body. Free testosterone refers to the hormone that is not bound to proteins and is readily available to act within the body. Another form of testosterone is bound to albumin, a protein found in the blood. However, the majority of testosterone is bound to sex hormone-binding globulin (SHBG) protein and remains inactive. When SHBG levels are low, there may be a higher concentration of free testosterone in the bloodstream.
Dihydrotestosterone (DHT) is a potent hormone derived from testosterone through an enzymatic process. DHT is primarily utilized by the body in the prostate, skin, and hair follicles. In fact, it is the actions of DHT and the sensitivity of hair follicles to DHT that contribute to hair loss.
Male pattern baldness follows a distinctive pattern. It typically begins with a receding hairline, especially at the temples, forming an "M" shape. As the condition progresses, the crown of the head, known as the vertex, also experiences hair loss. Eventually, these two areas meet, creating a characteristic "U" shape of hair around the sides and back of the head. Interestingly, male pattern baldness can even extend to other areas of the body, such as thinning chest hair.
Dihydrotestosterone (DHT) plays a significant role in hair loss. This hormone, derived from testosterone, acts on the hair follicles and can cause them to shrink over time. While DHT contributes to hair loss, it also serves important functions in the body, particularly in the prostate. Without DHT, the prostate does not develop normally. On the other hand, excessive levels of DHT can lead to conditions like benign prostatic hyperplasia (enlarged prostate).
Research suggests a potential connection between male pattern baldness and other health conditions. For instance, studies have found that men with vertex baldness, a specific pattern of hair loss, have a higher risk of developing prostate cancer compared to those without bald spots. Additionally, the risk of coronary artery disease is elevated in men with vertex bald spots. Ongoing investigations are exploring the relationship between DHT levels and metabolic syndrome, diabetes, and other health conditions.
Contrary to popular belief, it is not the amount of testosterone or DHT that directly causes hair loss. Rather, it is the sensitivity of hair follicles to these hormones that determines the likelihood of hair loss. This sensitivity is largely influenced by genetic factors. The AR gene, for instance, produces receptors on hair follicles that interact with testosterone and DHT. Individuals with highly sensitive receptors are more prone to experiencing hair loss, even with relatively low levels of DHT. Other genes are also believed to contribute to male pattern baldness. Furthermore, having close male relatives with male pattern baldness increases the risk of developing the condition.
There are several myths surrounding balding men and their testosterone levels. One common misconception is that men with male pattern baldness are more virile and have higher levels of testosterone. However, this is not necessarily true. In fact, men with male pattern baldness may have lower circulating levels of testosterone but higher levels of the enzyme that converts testosterone to DHT. Alternatively, genetic factors may dictate the sensitivity of hair follicles to testosterone and DHT, rather than the actual hormone levels.