Moisturizing creams contain more oil than water and, as a result, are also very effective. These also may feel a little greasy, but less so than ointments or petrolatum. Lotions are the most popular moisturizer, but because they contain more water than oil, they are not as effective. Humectants are a class of moisturizers which do not contain oil and may be classified as oil-free. These contain glycerin, propylene glycol, urea, hyaluronic acid, glycolic acid, and lactic acid.
Humectants are also extremely effective.
Some, such as alpha-hydroxy acids , actually improve the skin's ability to retain moisture. Things such as collagen, elastin, and keratin may add a little to the moisturizer, but they also drive the price of the moisturizer up more than it is worth. One important tip in the use of moisturizers is to apply to damp skin. This helps trap more moisture in the skin, keeping it better lubricated. This product is often applied before the regular moisturizer.