Miniaturization is when the hair follicle shrinks in diameter, causing the hair to appear thinner. In miniaturization, the hair follicle experiences a shorter anagen phase, so it is immediately distinguished from within, unless neighboring hairs also undergo the same kind of physical change. Eventually the diameter of the hair follicle shrinks to the point where new hair no longer grows. Miniaturization is an important identifier when visually inspecting the scalp for signs of hair loss. It almost always means that hair loss can be expected in the future. Miniaturization can also be defined as shorter, spindly hairs with a curly or “curly” appearance, although this is not standard in all cases.
What Causes Miniaturization?
Miniaturization is caused by a male sex hormone called dihydrotestosterone (DHT). Although DHT is classified as a male sex hormone, it is also produced by women, albeit in much smaller amounts than men. Therefore, it can also be observed in women. In both men and women, it can accumulate in large concentrations within the tissue of the scalp itself. This heavy concentration of DHT can eventually become so intense that it blocks the hair follicle from the scalp’s blood supply. In the absence of blood supply, the follicle itself lacks the nutrients to grow healthy terminal hairs and, as a result, begins to miniaturize. As the hair follicle miniaturizes, the hairs become less mature and appear more fluffy. Eventually, the hair follicle shrinks completely and goes completely dormant.
What Are Some Ways to Treat Miniaturization?
One of the most popular ways to solve this problem is to use medication. The goal is to reduce the amount of DHT in the body until it blocks the follicle’s access to its blood supply. Because DHT is created when testosterone is metabolized by an enzyme called 5 alpha reductase (5aR), a special type of medication called a 5aR inhibitor can prevent this enzyme reaction from occurring. 5aR inhibitors ultimately reduce the amount of DHT in the system, which prevents DHT from accumulating in the hair follicles and causing further hair loss.
Another way to overcome miniaturization is to have a hair transplant. Hair on the occipital scalp, that is, hair in the posterior head area between the ears, tends to be naturally resistant to the effects of DHT. Therefore, hair continues to grow when we remove the follicular units from the occipital scalp and transplant them to other areas experiencing hair loss, as we do in hair transplantation. Although the same amount of DHT is still present in the tissue of the scalp as before, newly transplanted follicular units are not affected, shed, as they are typically resistant to DHT at the cellular level due to genetics.
Is Everyone Sensitive to DHT?
No, not everyone is susceptible to hair loss even if they have plenty of DHT. An individual’s sensitivity to DHT is entirely dependent on their genetics. In addition, this gene itself can also become age-dependent, meaning that susceptibility to DHT does not manifest until adulthood. Simply put, some people experience hair loss due to miniaturization, and some never. This does not mean that DHT is the only determining factor for the development of alopecia. A person who is not vulnerable to DHT may experience hair loss due to a number of other unrelated conditions.