I know you get bombarded with inquires and can not answer each one. I figured I’d give it another shot. You answered my general inquiry about what is a “follicular unit” (1-4 terminal hairs including 1-2 permanent vellus hairs). This isn’t really another question, more a clarification on some of your other blog posts.
On your site you stated non-balding men and women have miniaturized hairs, and these hairs fall out eventually and a new hair grows in its place that most likely will be miniaturized as well. The percentage of these miniaturized hairs in non-balding men and women are low (under 20%). And if one looks at these hairs they are the vellus (short hairs) found in the follicular unit. Further.., (In every hair follicular unit there are one or two vellus hairs which are short and thin. They go through the hair cycle like their big brothers in that follicular unit.)
1.) I was curious.., say the < 20% miniaturized hairs in the FU for non-balding men / women, “Example (10% – 15%)”. Given the average 100,000 scalp hairs for an individual, a non-balding person would have 10,000 – 15,000 vellus hairs within their follicular units…give or take? Using the (10%-15% example) being less than 20,000 -20% figure.
2.) I also read on your blog in response to another inquiry that these “FU vellus hairs will always stay as vellus hairs”. Why would propecia / finastride not have an affect on these FU vellus hairs? Are they just genetically programmed to only grow to 1cm-2m? I know what it is supposed to do to the factors it is to affect. I didn’t know if the drug caused all hairs to grow and thicken / strengthen.
And by vellus hairs Im assuming this is what you referring per the definition from adermatology website (vellus hairs are in 1-2 cm length, light colored, occasionally pigmented and tiny shaped. They either have no pigments or have a little). Ranging in length of between a few mm – 2cm or so.
Vellus hairs are present in all follicular units, as are miniaturized hairs. As you stated, that vellus hairs do not grow long, have less bulk, and are without sebaceous glands attached to the upper shaft, typical of the “terminal hairs” that are the majority of hairs in the follicular unit.
There are many things I just don’t know about the subjects you raised. I don’t know what the effects of finasteride are on vellus hairs, but I do know that when the follicular units dies under the influence of the apoptotic “death” of genetic balding, the vellus hairs go with it. Miniaturized hairs cycle from anagen to telogen and will regrow, but the cycle is longer and the miniaturized hairs are those that are most impacted by the balding process. I see some miniaturized hairs in normal people, but the total count of these hairs is under 20% of the total. Many miniaturized hairs, when they go into telogen, just never return into another anagen cycle when genetic balding is present.
Under the influence of finasteride, I believe the miniaturized hairs return stronger with more bulk, particularly in younger men. When miniaturization is reversed in the few patients where I have seen almost full reversal of the balding process, the miniaturized hair must have gone through a hair cycle and come back as strong terminal hairs, but these converted miniaturized hairs probably will eventually suffer their final fate and die. When this happens, the vellus hairs almost certainly come back with the rejuvenated follicular unit under the influence of finasteride. I believe that whatever happens to the terminal hairs, happens to the vellus hairs and the miniaturized hairs in the presence of finasteride in the young man.
Generally, balding can be assessed with a good examination by a knowledgeable doctor by the time you’re 35 years old. Most advanced balding patterns appear in a man’s early 20s, and stability of the patterns are evident by the mid-thirties.