Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

White/Grey Hair: Twist

  1. Jul 12, 2008 #1
    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.

  2. jcsd
  3. Jul 24, 2008 #2
    According to


    "Drug treatment and alternative medicine. Several drugs can cause growing hair to stop its growth cycle and fall out. For example, drugs such as lithium (used to treat manic depression) and methotrexate (used to treat some forms of arthritis and cancer) can contribute to hair loss, revealing more gray strands. Interestingly, some cancer patients, whose gray hair falls out as a result of chemotherapy, experience regrowth of the lost strands in their original color. This phenomenon suggests that melanocytes that are producing less melanin can be stimulated to make more, although how this occurs remains a mystery."
  4. Jul 26, 2008 #3
    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 similiar 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).
  5. Sep 4, 2008 #4
    Reality_Patrol, funny you would write that, as just yesterday I was showing my husband how I only have grays where they show (and are presumably exposed to UV light). Maybe the melanin-producing cells get used-up over time when overstimulated by UV light?
  6. Sep 5, 2008 #5

    I'd have to know the locations on the scalp you have in mind to be certain. But from my observations, on the public at large, grey hairs first develop in locations that can be seen but that aren't exposed to UV light. Some examples: hair under the chin in men's beards, hair above the ears on the scalp. Both of these areas are "easily seen" but are least exposed to UV light from the sun.

    Of course you may have other areas of the scalp in mind.
  7. Sep 5, 2008 #6
    Point taken. Still, 15 years after first having those first few grays above my ears, my grays show at temples, along the top of my head where hair splits, and a lot in the back/top where the hairt naturally parts to reveal some skin, but not muchwhere else.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: White/Grey Hair: Twist
  1. Hair questions (Replies: 6)

  2. Hair growth. (Replies: 2)

  3. White/grey hair (Replies: 19)