Women smiling(Photo: Gabrielle Revere, Courtesy of Prevention)

THE TREATMENT: Ayurvedic Medicine

This system of traditional Indian healing relies on techniques such as diet changes, breathing exercises, and botanical medicine to treat patients based on their dosha, or "body type."

"The doshas seem to line up with skin types we're familiar with," says Jasmina Aganovic, an MIT-trained chemical and biological engineer and founder of the Stages of Beauty skin-care line. "The Vata dosha typically coincides with dry skin; Pitta coincides with sensitive; and Kapha, with oily or combination skin." Even so, there's no scientific evidence that treating your skin based on your dosha is beneficial, says Susan Stuart, MD, a dermatologist in San Diego.

However, there is proof that many of the plant-based ingredients used topically in Ayurvedic medicine can help you look younger. For example, "research shows that turmeric and ginger, both used frequently in Ayurvedic medicine, can reduce wrinkles," says Shyam Gupta, PhD, a chemist and founder of Bioderm Research, a cosmetic research company in Scotts-dale, AZ. And several studies show that grapeseed extract, another Ayurvedic ingredient, protects against photodamage.

BOTTOM LINE: Try products with ingredients like turmeric and ginger, but don't overhaul your beauty regimen based on your dosha just yet.

More from Prevention: 6 Botanicals for Younger-Looking Skin

THE TREATMENT: Alkaline Diet

A few studies have shown acidity can be damaging to the body, so it's thought by some that eating mostly alkaline-forming (acid-lowering) foods like fruits and vegetables may slow skin aging.

There's no research proving this theory. (Our bodies do a good job of regulating acidity regardless of diet.) But there is anecdotal support: "My clients who eat 80% alkaline-forming foods notice fewer lines and more hydrated skin in weeks," says nutritionist Kimberly Snyder.

BOTTOM LINE: The diet won't erase wrinkles, but eating more fruits and veggies improves overall health -- and that can only be good for skin.