The new science of cosmetics: skin creams no longer merely cover up blemishes and wrinkles; now they help slow the process of aging.

Byline: Tara Pepper And Karla Adam

Though she's just 27 years old, with a flawless complexion, account manager Bianca Bailey is on the hunt for scientific skin care in the beauty hall of Harrods. When it comes to aging, Bailey isn't taking chances. She grills several statuesque assistants before settling on Estee Lauder's DayWear for [pounds sterling]28, six times the cost of her regular moisturizer. She's not interested in the best-smelling cream or stylish packaging or something that promises to hydrate her skin. She's after antioxidants. "Who wants to look old if they don't have to?" she says.

Resurrecting and preserving a youthful complexion has been the holy grail of beauty since Cleopatra stepped into her legendary bath of milk more than 2,000 years ago. But until recently, most skin treatments were dubious, pricey creams and lotions that did little more than cover up blemishes and discolorations or add a healthy glow. Others were extreme and invasive, involving injections, operations or lasers. Now a new generation of skin-care products is drawing on the same genomics revolution that has transformed cancer research and agriculture. Scientists are using a greater understanding of how the genetic machinery of skin cells works to influence the aging process. Now when those fancy creams claim they can save Bailey's youthful appearance, they may be right.

The key area is the dermis, a layer of skin sandwiched between the outer epidermis and the deep hypodermis. The dermis contains blood vessels that nourish the skin, and proteins called elastin and collagen that keep it taut. As we age, our bodies struggle to replenish stores of collagen and elastin, and some people are genetically primed to break these down faster than others. Scientists can now measure an individual's genetic susceptibility to such rapid skin aging. For instance, Dermagenetics, a U.S. firm, can analyze your DNA and tell you what problems you're likely to face as you age. It distributes a self-test kit that involves swiping the inside of your cheek 10 to 12 times. The firm's scientists analyze the samples for the propensity of your skin to suffer collagen breakdown as well as its ability to handle oxygen and hydrogen free radicals (unpaired electrons that can damage DNA and proteins), environmental pollutants and mild irritation.

Scientists can then create a bespoke cream for each client's skin, using a combination of active ingredients selected to compensate for particular deficiencies. These were pinpointed after nearly three years of research in conjunction with Arch Chemicals, a Connecticut-based research firm, and include copper enzymes, superoxide dismutase (an antioxidant), and plant extracts such as red algae or clover. "We can't change your genes," says John Souza, a spokesman for Dermagenetics. "The only thing we can do is, if we know you don't handle hydrogen free radicals well, for instance, we'll give you something to help youwith that." The initial test costs [pounds sterling]135, then the cream--which lasts around two months--is [pounds sterling]125.

Such exclusive creams are just the tip of the iceberg when it comes to new, science-based products. Heavyweights like Procter & Gamble, Estee Lauder, L'Oreal, Unilever and Johnson & Johnson, which already employ thousands of researchers, are expanding their labs in an effort to capitalize on the latest science. P&G researchers, for instance, discovered that glucosamine, known in medical circles for its effects on arthritis, also blocked the production of melanin, which is responsible for those annoying brown spots. They then tested glucosamine in the ...