What are they?
Emollients are supple, lubricating agents that form a layer over the epidermis. There are both synthetic emollients, such as squalene and mineral oils, and natural emollients such as lanolin and cocoa butter.
What are they used for?
Emollients help to keep skin hydrated by locking in moisture, either by forming a barrier on the surface of the skin to prevent water evaporation (occlusive emollients) or by attracting and holding moisture in the upper layers of the skin (humectant emollients). Medically they are used in products for sufferers of eczema and psoriasis due to their moisture-promoting properties, but in skincare are widely used to increase hydration - particularly for drier skin types and for products designed for use in cold weather. Think of the almost painful chill of a New York winter - emollient creams are unbeatable at providing a barrier between your skin and the elements and reducing dryness and flaking.
What are the pros and cons of using them?
By creating that barrier over the epidermis, emollients prevent moisture from getting out, and environmental aggressors from getting in. Those with dry complexions will find them useful in protecting their skin, keeping it soft and smooth, and reducing redness. However, this same barrier function may cause problems for easily congested skin, contributing to blocked pores in cases where the product is too rich. Irritation can also occur in some instances.
Which products can I find them in?
Since their main function is to promote moisture, emollients are generally found in rich creams designed for drier skin types. Try Kiehl's Ultra Facial Moisturizer, Ren Vita Mineral Emollient Rescue Cream or Lanolips 101 Ointment.