The old gray hair, she ain’t what she used to be


Look, I hate to be the one to break it to you, but you’re growing older. Every second. Even worse, so am I.

There are many manifestations of the aging process, most of which are far too depressing to go into, especially on a morning in late February. Still, we must all face facts sooner or later, and for many of us, the “sooner” arrives when we look in a mirror and notice…a gray hair.

It’s the advance scout of an army of pale invaders to our scalp, and it’s been the focus of speculation and research for a long, long time.

Now a new paper has been published that claims to have solved the mystery of why we go gray. The culprit, it seems, is none other than hydrogen peroxide.

“But wait!” I hear you cry. “I’ve never bleached my hair. Why am I going gray?”

Ah, you misunderstand. The fault lies not in the hydrogen peroxide applied from without, but hydrogen peroxide that arises from within.

Or, as Gerald Weissman, editor-in-chief of the Federation of the American Societies for Experimental Biology (FASEB) Journal, which published the study, puts it succinctly, “All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot. We bleach our hair pigment from within, and our hair turns gray and then white.”

Normally, hair is pigmented as it’s produced by hair follicles. Your exact hair colour is determined by how much of two pigments, eumelanin and phomelanin, are present. Eumelanin determines the range from blonde to black. If you just have a little, you’ll have light hair; if you have a lot, you’ll have dark hair. Phomelanin determines how red your hair is. So if you have very little of either eumelanin or phomelanin, you’ll be blonde; if you have very little eumelanin but lots of phomelanin, you’ll be a red-head; if you have lots of eumelanin and lots of phomelanin, you’ll likely have dark brown hair, and so on.

But gray hair is something else: it’s an absence of pigment. As hair follicles age, they stop producing pigment, and no one has been entirely sure why, though there have been lots of theories.

In the new study, a group of European researchers examined cell cultures of human hair follicles to see exactly what happens to them as they age. The loss of pigmentation turned out to be a complicated process.

Normally, an enzyme called catalase breaks hydrogen peroxide into water and oxygen, but as the hair follicles aged, that enzyme decreased. As a result, hydrogen peroxide began to build up. Two other enzymes, MSR A and B, normally repair the damage caused by hydrogen peroxide–but their levels also decreased as the follicle aged.

Not only that, but high levels of hydrogen peroxide and low levels of MSR A and B disrupt the formation of yet another enzyme, called tyrosinase, that leads to the production of hair pigments.

So while it’s hydrogen peroxide that causes your hair to turn gray, it’s not like it’s bleaching it white after it’s grown, the way an external application of hydrogen peroxide does: rather, it prevents the hair from getting any colour to begin with.

Which is all very well, but is only of academic interest if it turns out that, like the weather, graying hair is something everyone talks about, but nobody can do anything about.

The researchers have hopes that their research might actually point the way to an effective treatment for graying hair, however.

They suggest that it might be possible to do something about the loss of MSR A and MSR B, enabling the hair follicle to continue to repair the damage caused by hydrogen peroxide, allowing it to continue proper pigmentation of the hair it produces. “A corrected repair offers certainly an interesting target for the graying hair,” is the concluding, if somewhat Yoda-like, sentence of their paper.

Or as the aforementioned Weissman puts it, “This research…is an important first step to get at the root of the problem, so to speak.”

In the meantime, do what I do: avoid brightly lit bathroom mirrors.

It’s amazing how easily one can learn to shave in the dark.

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    • Janet on February 23, 2009 at 3:13 pm
    • Reply

    I have found hairs of my own that were brown at the root and white further out. I guess the body sometimes rallies its resources or something and reestablishes the younger chemical balance.

    In my case, not for enough hairs…

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