Bronco said:
Hello all,
So I realize the topic of how to reverse the greying process has been beaten to death with no clear solutions yet. However, my question is whether any drugs have been shown to cause the greying process in hairs, with no stem cell side effects.
Anyone?
Well I don't know about any drug but I do have a hypothesis as to what causes premature grey and what can reverse it. I've shared it on another thread, but it had no replies. All the smart cookies on the board probably thought it was silly, so I'll turn it up a notch to make it "more serious" this time. Here goes:
First, the biological perspective.
Hair fibers are made of keratin, much like finger and toe nails. The hair keratin, much like finger and toe nail keratin, is essentially transparent (whitish when diffuse). Hair derives its color from a pigment that's produced in the base of the hair follicle that coats the outside of the keratin (naturally white) composed hair shaft. The pigment produced in the hair follicle is synthesized by specialized cells called melanocytes. So, grey hair is actually "nearly pigment free" hair, while white hair is "absolutely pigment free" hair. Thus, the greying of hair results from the melanocytes ceasing the production of pigmentation in the hair follicles. So, the question of how to restore how color is directly related to the question of how to reactivate the synthesis of pigmentation in the hair follicles, or more simply how to get the melanocytes to start working again.
The number of melanocytes, as a local percentage of the total cell population in the hair follicle, has been shown to decrease with age. But, their number never goes to zero.
Melanocytes are also responsible for skin color, by injecting the same type of pigmentation into the skin. Thus, hair color and skin color are very similar biological processes.
Second, the physiological perspective.
So the next question is why does the body need hair color at all? The answer is trivially obvious since the answer is known when it comes to skin coloration. Natural selection drove the evolution of skin and hair color as an adaptation to improve survivability in response to the local "photo-environment". Simply put, it's been shown that skin color variations in indigenous populations around the world maximally correlates to annual UV exposure levels for the local area. To much UV is just as bad as not enough UV, otherwise natural selection would have eliminated the caucasian races by now.
Lastly, the hypotheses:
(A) Simply put, melanocytes in the hair follicles are sensitive to UV exposure just like the melanocytes in the skin. In other words, increasing the hair follicle melanocyte's UV exposure levels triggers an increase in their pigmentation activity just like it does in the skin, where the process is called tanning. The amount, duration and frequency of UV exposure required to induce a change in the activity level would likely be different given their different physiological roles.
Many might view (A) as a "new hypothesis" that needs to be proven. Maybe so, but no more so than what any critic is implicitly arguing. Let's call this (B):
B. Simply put, melanocytes in the hair follicles are INSENSITIVE to UV exposure unlike the melanocytes in the skin. In other words, increasing the hair follicle melanocyte's UV exposure levels will NOT trigger an increase in pigmentation like it does in the skin, where the process is called tanning. The amount, duration and frequency of UV exposure has no effect on hair follicle melanocyte's pigmentation activity.
If one takes the time to objectively consider how many assumptions goes into (B), it will be seen how equally unsupported, and actually less plausible, it is compared to (A).