Could science put an end to bad hair days?

Effects of repeated dyeing
Minerals such as calcium, magnesium and copper cling to your hair every time you wash it with tap water. Calcium and magnesium are relatively benign; copper is not. In the highly alkaline environment of ammonia-based hair dye (normally a pH of 10 or 11), Marsh and her colleagues found that copper can combine with hydrogen peroxide to form the über-reactive and indiscriminate assailants known as hydroxyl radicals.

Repeated dyeing can strain and chip away the cuticle — leaving hair harder to control even as determined brushers become unwitting accomplices in destroying more of the unstable shingle-like cells. And with less of the cuticle to stop them, the radicals are free to attack the protein fibers wound up within the cortex by forcing apart their structural supports and fraying their ends. Hence, those nasty split ends. “Yeah, I could get great color, but my hair will be a mess by the end of it,” Marsh said.

“It’s a bit of a vicious cycle,” added Neuser. “Even if you don’t color your hair, you have a small amount of copper from the tap water.” With every dye treatment, the hydroxyl radicals poke holes in the hair’s waterproofing and make it increasingly porous, allowing more copper to get in during your next shampoo. People who repeatedly color their hair, in fact, end up accumulating significant copper levels and compounding the damage.

So how can regular dyers stop the buildup? One strategy is to take out the mineral by binding it to something else. With far more calcium and other minerals around, that binding compound would have to be fairly choosy. “You have 100 times more calcium in the water and as a result, in your hair,” Neuser said. “If you had something that would react with both, it would react with all the calcium before it saw any of the copper.”

A few years ago, P & G researchers discovered that an inscrutably-named compound abbreviated EDDS has little taste for calcium but eagerly gloms onto copper, leaving it unavailable for radical mischief-making. After five colorings and 12 shampoos, clumps of human hair showed far less copper-induced damage to their cuticle layers. Salon volunteers likewise noticed a difference. Buoyed by the success, the company added EDDS to its Nice 'N Easy line of dyes.

A new recipe
Another solution has been to try a kinder “bleaching engine,” one the company is calling AminoGlycine. Instead of using pungent ammonia to react with the hydrogen peroxide, the researchers are using a well-known alternative called ammonium carbonate, which does its job at the milder pH of 9. The new mix works well for delivering dye, though it can’t be used on its own because it does little to curb the damage from those radicals. After testing about 50 compounds, however, the chemists found that adding glycine (a building block for proteins) gobbles up many of the troublemakers.

Similar “radical scavengers,” as they’re known, have been sought out for anti-aging and anti-pollution formulas. For dye jobs, the new scavenger-rich recipe has meant less bother in about 10 minutes, giving the resulting product its name: Perfect 10.

Trefor Evans, a hair expert at the New Jersey-based TRI/Princeton nonprofit research organization, said he wasn’t familiar enough with Procter & Gamble’s radical-reducing methods to comment on their merits. But Evans, whose nonprofit organization has worked with the company on other projects, said anything that can reduce a dye’s pH is “definitely a good thing to do.”

A high pH, he said, causes the hair’s cortex to swell considerably, which can unduly strain the surrounding cortex layer. “Think of it like the shingles on the roof of a house,” Evans said. “If all of a sudden, the house swelled by 20 percent, then those shingles would be put under a lot of stress.” Eventually, the house will return to its normal size, he said, “but the shingles won’t be in a pristine condition.”

Proctor & Gamble is far from alone in trying to refine the art of the permanent dye job. And despite the new solution, there’s still plenty of room for a completely hair-friendly process, Marsh said. “Ultimately, you’d want one that won’t damage it at all” — the Holy Grail of the industry. In the meantime, the two company chemists are not shying away from their own creation. “I just used it a couple of weeks ago,” Neuser said. “I looked in the mirror and I could see my roots.”

Ash blonde to the rescue.

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