New hair growth question

[Follicle1984]

Hi all.

I just wondered if anyone could help me with this question.

If a hair falls out after the resting telogen phase and a new hair starts to grow (in the anagen phase), how thick will the new hairs shaft be? Do all terminal hairs start out in appearance as tiny colourless vellus hairs when regrowing?

I'm trying to work out, if on a new hair treatment one starts to see new terminal hairs, could this be the start of new terminal hairs? Or are they likely just miniaturised hairs which will unlikely get any thicker? 

I know in androgentic alopecia they say there is progressive miniaturisation of the hair follicle and with each subsequent hair cucle the hair is slightly thinner in its shaft and shorter in length. If this process is reversed by a treatment, how quickly does a hair revert back to the thickness and diameter of a terminal hair unaffected by androgenetic alopecia? 

Sometimes you see pictures of an amazing (and quick...matter of months) transformation where seeming empty hair zones now are filled with terminal hairs. I presume they have haven't had time for multiple hair cycles for this hair to gradually thicken up...so does the follicle just beef up quickly and then the next hair is pre-androgentic alopecia size and thickness?

But I guess my original question is...even at first with any terminal hair (even in a male completely unaffected by androgenetic alopecia)...if you looked at a brand new strand of an anagen follicle's terminal hair...would this appear like a vellum hair when it popped out of the scalp and was only afew mm long? It's obviously different to if you just shaved your head and then the new hairs shaft is already at a thick (and stubble like) diameter isn't it? Or should all new anagen terminal hairs start out thicker and with colour? 

I hope that's clear. Difficult to articulate.

Cheers

Edited February 19, 2023 by Follicle1984

[Dr. Guncel Ozturk]

If a hair falls out after the resting telogen phase, a new hair will start to grow in the anagen phase, which is the active growth phase. This new hair can be either a vellus hair or a terminal hair, depending on the individual's hair growth pattern.

Vellus hairs are typically finer and lighter in color, while terminal hairs are thicker and have a more noticeable color. When hair regrows after a shedding phase, it is possible for vellus hairs to transform into terminal hairs over time. However, this process can take several hair cycles and may not occur in all individuals. Androgenetic alopecia is characterized by the progressive miniaturization of the hair follicle, causing the hair to become thinner in shaft diameter and shorter in length. If a treatment is able to reverse this process, it is possible for the hair to revert back to its pre-androgenetic alopecia thickness, although the rate of this process can vary greatly depending on the individual and the treatment.

In general, new hair growth can be seen as thicker and with more color, but it can also start out as a fine vellus hair.