Vaseline can be used in a variety of skin-care products.

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If someone told you that a miracle skin cream exists that can lock in natural moisture, heal wounds, soothe irritation and prevent wrinkles -- and that on top of that, it costs just pennies per ounce -- would you run out to the store to buy it? Chances are you don't have to; it may already be in your home. We're talking about good old petroleum jelly, or, as it's known by its most popular brand name, Vaseline.

Supermodel and television host Tyra Banks has sworn by Vaseline's anti-aging powers; in 2006 she famously gave each studio audience member a tub of the greasy goop while jumping up and down and screaming about her "biggest beauty secret ever." [Source: YouTube, TreSugar] And she's not the only one who loves it; dermatologists recommend it too!

"It's actually an excellent product -- probably our safest product -- because it's incredibly rare for it to irritate anyone's skin or cause an allergic reaction," says Chris Adigun, assistant professor of dermatology at NYU Langone Medical Center in New York City. "That's why it's so great for persistent dryness or dry spots around the eyes or the lips."

Jeffrey Benabio, MD, a dermatologist with Kaiser Permanente in San Diego, recommends Vaseline to his patients with severely dry skin, eczema, or psoriasis. The fact that it's so inexpensive means that people are less hesitant to use a lot of it, he adds.

"People think they have to go buy really expensive eczema cream, for example, but then they don't want to use a lot because they paid so much," Benabio explains. "But because Vaseline is so economical, they can get into good habits of really using a lot, which is what you need to do to see improvement."

A study published in 1993 discovered that petroleum jelly does more than just seal in moisture – it also repairs fat cells impaired by dry skin [Ghadially].

Because it's derived from petroleum, people may be concerned about absorbing toxic, oil-based chemicals into the body. But research has shown that the jelly form used in cosmetics is too thick to seep into the skin, and is only dangerous if ingested. [Source: Go Ask Alice!] In fact, Vaseline can also be used to seal and treat minor wounds and burns, and is safe to use on cracked, chapped, or irritated skin. (In cold weather, it also acts as a shield against windburn for this same reason.)

The only obvious downside to using Vaseline (besides its slippery, shiny, and sometimes messy texture) is the fact that it's made from fossil fuels, rather than sustainable, renewable resources. For eco-conscious consumers who want other options, says Adigun, there are also beeswax or plant-based alternatives that will form a similar type of barrier on the skin and can be used in the same way.