How Does Hair Loss Occur in Androgenetic Alopecia?

Androgenetic alopecia is that common form of hair loss that is generally part of the aging process. In men, it’s called male-pattern hair loss...

It’s caused by several genetic and environmental influences in ways that are not totally understood. What we do know is that those influences change the hormonal environment of the hair follicle causing the follicle to become smaller and thinner with less blood supply. These changes are called miniaturization of the hair follicle.

So, what is miniaturization?

To understand miniaturization, you need to first understand the different stages that hair follicles go through. Hair has four stages, anagen, catagen, telogen, and exogen phases. So, normally hair can spend years in the anagen or growth stage. Then it spends months in the catagen or resting phase.

During the exogen phase, the hair falls out. Then the hair growth cycle starts again. During miniaturization, these phases speed up and hair spends less time in the anagen phase. This is one reason why older individuals often cannot grow hair as long as they did when they were young—hairs go into the catagen phase faster than they used to.

Also, the physiology of the hair follicle changes. The hair follicle has tiny blood vessels that nourish it and a muscle at the base. As miniaturization continues, both the blood vessels and the muscle shrink and pull away from the follicle. Where this little muscle, called the arrector pili muscle, is normally attached to the follicle, it is eventually replaced with fat.

During this miniaturization process, the hair growing out of the follicle becomes thinner, more fragile, and shorter, until there is no hair left in the follicle at all. Eventually, the follicle stops growing hair.

Several hairs grow out of each follicle, called a follicular unit. And each hair within the same follicular unit may be in a different stage of growth. But, obviously, as the whole follicular unit changes its structure, all the hairs within the unit are affected.

Some follicular units on the head seem to be immune to this miniaturization. These are the follicles toward the back and base of the head. Sometimes these hairs don’t even turn grey like on the rest of the head.

For a whole host of reasons, during miniaturization hair follicles seem to be more sensitive to or cued by the hormone, dihydrotestosterone (DHT), in the scalp--which is present in both men and women. So, some of the treatments for hair loss are aimed at DHT, blocking it or minimizing its presence in the scalp.

Hair loss is complicated, and as we said at the beginning, not fully understood. There is not one cause, but several causes likely working together to make hair fall out. But there is new research all the time, and there are currently several different types of treatments that really work. Hair regrowth is more effective when your follicles are still producing hair, so don’t hesitate to talk to us about treatment, and let us help you regrow your hair.

Anyone suffering from sudden and significant hair loss should see his or her family doctor, but we are here for you when you’re ready to start treatment for hair loss. If you have any questions about treatment for hair loss or any of our products, we encourage you to call us directly at (844) 280-4680.

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