Moisturizers prevent and treat dry skin, protect sensitive skin, improve skin tone and texture, and mask imperfections. Moisturizers hold water in the outermost layer of skin. They also act as a temporary barrier, allowing damaged surface cells time to repair themselves. Moisturizers contain many ingredients, please see below.

• Humectants (urea, glycerin, alpha hydroxyl acids, lactic acid). These are substances that absorb water from the air and hold the moisture in the skin. They need very high humidity levels, in order to be effective. These are also useful in softening thickened or scaly skin.
• Emollients (butyl stearate, glycerin, lanolin, mineral oil, petrolatum). These fill in the space between the cells in the skin, helping replarce lipids and thus smoothing and lubricating rough skin. They are either oil or water based. Oil-based creams leave a slight residue on the skin and have more staying power than water-based creams do. Water-based creams are easier to apply and don’t leave much of a residue.
• Fragrances. Most moisturizers include fragrances, which give the product a fresh, pleasing odor and cover up the smell of other ingredients.
• Preservatives. Any product that contains water and oil must contain one or more preservatives to help prevent bacterial contamination after the product is opened. These ingredients can cause skin reactions.

Moisturizers can also include other ingredients as well, such as vitamins, minerals, plant extracts, sunscreens, and sunless tanners. Some also contain ingredients that claim to boost your body’s production of collagens and elastin, diminish stretch marks, smooth out wrinkles, unblock pores, and exfoliate dead skin cells. Many of these claims are unapproved. Moisturizers are cosmetics, so the Food and Drug Administration regulates them differently than they do drugs, which means products don’t undergo rigorous testing for safety and effectiveness.

The type of moisturizer depends on many factors, including skin type, your age, and whether or not you have specific conditions.

Getting the Most Out of Your Moisturizer:

• Find a moisturizer that fits your skin type and makes your skin look and feel good.
• Remember that cost does not have a definite relationship to effectiveness.
• Apply moisturizers immediately after bathing.
• Apply moisturizer to your hands and body as needed.
• Do not use heavy creams on your face, unless your skin is very dry.

Source: “Moisturizers 101: The basics of softer skin.” (Mayo Clinic)