Another day, another theory on wrinkle prevention.

The first long-term study measuring the speed of wrinkle development was published in the June issue of the British Journal of Dermatology. It found that women with well-hydrated skin developed wrinkles at a slower rate than those with parched skin.

The eight-year study, which followed 122 females aged ten to 72 and was funded by Olay, showed that for a typical 28-year-old woman with dry skin, the amount of visible wrinkles increase by 52 percent by the time she reaches 36. Her wrinkles would increase by just 22 per cent by the same age if she had well-hydrated skin.

Now, you may find it pretty convenient that a moisturizer-touting study was commissioned by a major moisturizer manufacturer, but other recent studies have also supported this theory.

We recently wrote about a Consumer Reports test on anti-wrinkle serums which found most of the products ineffective and concluded,"Consumers should focus on getting back to the basics like moisturizing and shielding skin from the sun. Beyond that, if you want to try an over-the-counter anti-wrinkle product, realize that the results may be minimal if any," said Jamie Hirsh, Associate Editor at Consumer Reports Health.

According do the Daily Mail, the Olay-funded study took photographs of the participating women eight years ago, with their faces in a neutral expression and then smiling, with the hope of establishing whether expression wrinkles - the ones that appear when your face creases up into a smile - become persistent wrinkles. The hydration levels of each woman's skin at the time was also measured and noted. Eight years later, they re-took photographs of the women and had the images examined by expert graders.

While this study would have you believe that purely using moisturizer will dramatically help prevent wrinkles, experts agree wearing sunscreen is the single most important thing you can do to help prevent the signs of aging, with exfoliation and moisturization as additional helpful steps.

Check out summer's best new sunscreens.