Run an online search for snail essence , and youll find a whole host of skincare products that feature snail secretions yes, the goo that comes out of a snail as a key ingredient.

Used as a skin treatment in ancient Greece , the substance has made a big comeback in recent years as a Korean-based beauty trend . Brands like Tony Moly and Missha sell moisturizers , masks , makeup creams and serums with snail slime in them, and a snail-infused EscarGlow facial has made its gooey mark on New York City.

New York City dermatologist Tabasum Mir told HuffPost exactly where snail secretions come from.

When snails are agitated, they excrete a thick fluid as a means to protect themselves, Mir said. When concentrated, this slimy snail mucin is said to aid human skin by hydrating, preventing aging and improving wrinkles and scars .

Popular products generally run between $6 (for a snail gel mask by Missha) to $60 (for Tony Molys timeless ferment snail essence set ).

So, is it worth it?

Likely not: Snail mucin is packed with nutrients , but theres no guarantee itll be effective as a skin treatment, Marie Jhin , a dermatologist at California Pacific Medical Center, told HuffPost.

The slime is not consistently concentrated and [benefits] may depend on the type of snail and amount excreted, she said. The way the slime is processed is not easily done and universal, thus the formulation of the slime may not be the same [across products].