Chris Gummer believes a single strand of hair can be devastating.
"One gray fiber is enough to shatter a life," said Gummer, a senior research fellow at Procter & Gamble labs in London, U.K. "Even if someone has 20 million dark hairs on her head, this single strand can create a tremendous cascade of grief."
Someday soon, Gummer and others say, gray hair may be forever postponed by taking a pill that would prevent the estimated 110,000 hairs on the average head from going gray.
"It could be like using toothpaste to prevent tooth decay," said Gummer.
Turning White Mice Black
The possibility of tinkering with the scalp's genes to prevent the onset of graying gained momentum four years ago when scientists made an albino mouse turn black in one patch.
Kyonggeun Yoon and Vitaly Alexeev of Jefferson Medical College in Philadelphia created molecules of DNA that, when introduced to the mutant DNA within the albino mouse's hair follicles, corrected the mutation and restored pigment to its hair.
"The mutation was corrected," said Alexeev. "The hair turned black."
For Yoon and Alexeev, the experiment was exciting because it presented a new method that doctors could use to treat painful genetic skin disorders, such as epidermolysis bullosa, a condition that creates open sores and blisters on the skin's surface.
"As a localized treatment, it might lessen the pain and perhaps ease this very painful disease," said Yoon.
For cosmetic scientists, meanwhile, it offered a different kind of potential. If the gene therapy could make the white hair of an albino mouse turn black, it should also help banish gray hair — without dyes.
"I do think we'll achieve it within 10 years, but the challenges in delivering it will be quite hard," said Gummer.
In fact, most agree there are some formidable hurdles yet ahead since the target is a complex one.
About 85 to 90 percent of a person's some 110,000 hairs are actively growing while the remaining are dormant. Each strand grows for three to five years and then falls out after about four months, says Gummer. People generally shed about 50 to 100 strands of hair daily.
Each strand of hair is made of the protein keratin and grows out of a follicle in the scalp's skin that has cells filled with melanin. As a strand grows, these cells donate a little color to the hair cells in the form of tiny granules of melanin. One form of melanin, called pheomelanin, creates blondes and redheads, while another, eumelanin, colors the hair of those with brown or black hair.
The problem is these pigment cells gradually stop producing melanin and without the chemical, our hair turns white or gray. This generally starts happening around age 30 in men and age 35 in women. And because the pigment cells start failing one by one, we also grow gray hairs one by one — producing the salt and pepper look.
In some rare cases, people under great stress or with some forms of illness appear to "go gray overnight." Researchers believe what really happens in these unusual cases is all of the person's pigmented hair falls out, leaving only the gray strands on their head.
Some studies have shown that poor health, anemia, thyroid problems and possibly smoking can cause hair to go gray sooner. But graying is normally a gradual process and scientists don't yet understand why the pigment cells stop producing melanin. In fact, the cells always contain melanin's building blocks, melanocytes and melanosomes — just not melanin, itself. Somehow the melanin production system goes dormant.
Could Yoon and Alexeev's method be used to coax these damaged pigment cells back to life? Possibly, says Gummer, but there are hazards.
Tip-Toeing Around Skin Cells
"There are all these pigment cells waiting to be turned back on," he said. "But the skin itself contains a lot of pigment cells. So you could end up with a dark scalp as well. That would look horrible, obviously."
Because melanin is important in protecting the skin from sun damage, scientists need to be careful not to tweak nearby cells so they lose their melanin. There's also the trick of ensuring that the pigment cells, if turned back on, continue to stay on. In the mouse experiment, for example, the repaired pigment cells produced black hair for just two months before going white again.
"The target cells — epidermal stem cells — are not very well understood right now," said Yoon. "We need to understand these cells better or the field will not advance."
In the meantime, people can find color in a box or bottle — or regard their gray a dignified sign of maturity.