The New Science of Perfect Skin

ONE Skin 101 Along with the rest of the body, human skin has evolved over roughly 7,500 generations, give or take a few. These genetically driven changes have been fueled over the millennia by selection for what is optimal for one thing and one thing only: sex. Yes, that's right: sex, as in human reproduction. Biologically speaking, skin has the same ultimate purpose as the rest of the human body: contributing to the continuation of the species. As a result, the genes that were passed down to you and everyone you know are the good ones that produced healthy and glowing skin, protected the body, and, most of all, attracted a mate. The bad skin genes that caused disease, weakened the individual, and turned off potential partners didn't get passed on and were eventually lost from the gene pool. The way people look during the different stages of life fits in with this biological imperative. A baby's skin is soft and smooth to encourage its mother to care for it. During puberty, skin may look aggravated, angry, and out of sorts-which it is. But it's just adapting like the rest of the body to the surge of hormones and physical changes that transform children into adults. (This is, not surprisingly, little consolation to a teenager who suddenly develops terrible breakouts!) From a biological point of view, the childbearing years are when skin really counts, as people who look their best are much more likely to attract a mate. Those with clear, radiant skin get the highest marks in the gene-pool competition, so it's no wonder that the skin's genetic program is designed to reach a crescendo of health and fitness during the courtship and reproduction years. In most cases, skin in the twenties and early thirties doesn't require much more than cleansing, moisturizing, and daily protection from the sun. Remember, these are the years that generations of human evolution have selected for maximum health with minimum maintenance. Skin genes controlling shape and texture are not the only determining factor of who beds down with whom, of course, but during the mating ritual, they provide, often unconsciously and in a single glance, an enormous amount of information. A man looking at a woman will make instant judgments about her overall health, fitness, and the degree to which she possesses the "it" factor known as sex appeal. At the same time, a woman is also gathering vital information from her instant judgment about a man's looks. This was proven by a recent study at the University of California, Santa Barbara, which found that women can identify those men with higher testosterone levels and select those with high paternal quality and those who especially like infants just by looking at photographs of the men's faces. Bottom line: Skin was built for sex. Skin health peaks during the reproductive years; after that, we need help. THE SKIN YOU'RE IN Your skin is a whole lot more than an inert overcoat, or something you might think of as cellular Saran wrap. It's a living thing-the largest organ of your body and one that changes dynamically over the course of your lifetime. Like most organs, skin has two main layers: the dermis, the thick layer on the bottom; and the epidermis, the thin layer of cells on the surface above. The living dermis is mainly comprised of cells called fibroblasts. These fibroblasts are surrounded by collagen and elastin fibers to form the stretchy supporting structure of the skin. The dermis is also infused with blood vessels to supply nutrients and take away waste, as well as nerves for exquisitely delicate sensation. Hair and oil and sweat glands are all anchored in the dermis and poke or wind their way out to the surface. Perched on top of the dermis is the epidermis, a layer no more than about twenty cells deep. The cells making up this layer are called keratinocytes. They divide rapidly, but they only growYarosh, Daniel B. is the author of 'The New Science of Perfect Skin' with ISBN 9780767925396 and ISBN 0767925394.