Is Slugging the Secret to Hydrated, Healthy Skin?

Coppola stresses that it's important to remember that petroleum jelly is not a moisturizer. It is a barrier agent that helps lock in moisture by preventing water loss. It also locks in other products, which can be good and bad.

"Some of the side effects from skin care products may be exacerbated by applying petroleum jelly on top because they aren't exposed to the air, leakage is limited and the natural vehicle within which they are formulated to deliver the active ingredients to the skin is altered," says Coppola. "Caution should be exercised to determine tolerance for the increased concentration of skin care products layered underneath the petroleum jelly."

Slugging should always be the last step in a routine. If you've experienced sensitivity with any skin care product previously, don't apply them during a slugging session. Do a patch test your first time slugging and always monitor your skin for any adverse reactions.

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