Skin Moisturizer Basics

Skin moisturizer ingredients can be divided into three categories: humectants, emollients and preservatives. Humectants, such as urea, glycerin and alpha hydroxy acids, help absorb moisture from the air and hold it in the skin. Emollients, such as lanolin, mineral oil and petrolatum, help fill in spaces between skin cells, lubricating and smoothing the skin. Preservatives help prevent bacteria growth in moisturizers. Other ingredients that moisturizers may contain include vitamins, minerals, plant extracts and fragrances [source: Kraft].

The emollient part of moisturizers can be oil-based or water-based. Oil-based emollients are heavier and may leave a residue on your skin, so they're best for people who have dry skin that needs intensive moisturizing. Water-based emollients, on the other hand, are lighter and less greasy, which make them ideal for people with normal, oily or acne-prone skin [source: Bruno].

If you want to avoid using moisturizers made from animal-based additives, such as animal fat, beeswax and milk protein, look for vegan or environmentally friendly skincare lines that contain synthetic moisturizers or vegetable glycerin [source: Carpenter].

Now that you understand how moisturizers keep your skin soft and smooth, read on to learn about the different types of moisturizers.

Many people with oily skin avoid using moisturizers because they think it'll just make their skin oilier. However, the oil on your skin seals in moisture -- it doesn't replace the moisture you lose, especially as you age [source: Bouchez]. In addition, many people with oily skin also have acne -- which occurs when oil and dead skin cells clog pores -- and acne treatments can often dry out skin [source: WebMD]. If you want to maintain a clear complexion and keep your skin moisturized, use an oil-free, noncomedogenic moisturizer [source: WebMD].

Noncomedogenic moisturizers won't clog your pores and are less likely to cause acne breakouts than regular moisturizers. Their name comes from the word "comedones." Comedones are hair follicles that enlarge when they fill with dirt and oil -- they appear as blackheads or whiteheads on the skin. When comedones become inflamed, they can turn pink or red and fill with pus -- these are the pimples normally associated with acne. Noncomedogenic moisturizers may also be called nonacnegenic moisturizers, especially if they're specifically designed to treat acne [source: SkinCareGuide.com]

Noncomedogenic moisturizers have a lighter feel than regular moisturizers, and many are oil-free, so they won't leave additional oil on your skin. Most labels will advertise if a moisturizer is noncomedogenic or oil-free. If you have acne, doctors recommend using all noncomedogenic products, including moisturizers, cleansers, shampoo, makeup and sunscreen.

Moisturizers help keep skin smooth and healthy, but they also provide protection from harmful irritants in the environment. Read on to learn how moisturizers protect your skin.

In a way, all moisturizers work to protect your skin: They add moisture to the stratum corneum, and they form a thin barrier designed to retain that moisture. Still, there are some moisturizers that are more effective at creating that protective barrier. As the outermost layer of your skin, the stratum corneum protects your skin from irritants such as chemicals, free radicals and the sun's ultraviolet rays. This part of your skin works hard to protect you, and using a protective moisturizer can help keep your stratum corneum healthy [source: Elias].

Protective moisturizers often contain occlusive emollients, antioxidants and sunscreens. Occlusive emollients are ingredients that add a layer of oil to the top of the stratum corneum to prevent water loss and protect skin [source: New Zealand Dermatological Society]. Antioxidants fight free radicals, the unstable molecules that occur from sun exposure and pollution that can destroy skin's collagen [source: Bouchez]. Protective moisturizers typically contain sunscreen with a sun protection factor of at least 15 to protect skin from the sun's UV rays [source: Clark]. These rays can cause sunburn, wrinkles and skin cancer.

Keep reading to learn about specialized moisturizers you can use to treat wrinkles, stretch marks and other skin problems.

Whether you want to fight wrinkles, fade stretch marks or fake a sun-kissed glow, there's a moisturizer for you. One of the most common specialized moisturizers is anti-aging cream. Anti-aging creams typically contain collagen and elastin, which are proteins that help keep your skin toned and flexible [source: Mayo Clinic]. While these products may temporarily plump up wrinkles, topical creams can't replace the collagen and elastin from your skin's deeper layers.

Other ingredients designed to help smooth out wrinkles include alpha-hydroxy acids, retinoids, vitamin C, copper peptides and coenzyme Q10. Alpha-hydroxy acids help lift the top layer of dead skin cells to reduce the appearance of fine lines, and these acids may also stimulate collagen production. Retinoids reduce wrinkles and repair sun damage, and vitamin C can increase collagen production and protect skin from UV rays [source: Bouchez]. Copper peptides stimulate collagen production, and coenzyme Q10 reduces fine lines and provides protection from sun damage [source: Mayo Clinic].

Many of these anti-aging ingredients can also be found in toning and firming lotions. Coenzyme Q10 is used to improve skin's texture and reduce cellulite, and studies show that copper peptides smooth and firm skin [source: Cleveland Clinic]. Lotions that contain dimethylaminoethanol can also help firm skin and fight wrinkles by fighting free radicals and lifting sagging skin [source: Schwartz].

Although there are over-the-counter moisturizers that claim to get rid of stretch marks, doctors say they're not particularly effective [source: WebMD]. However, some research shows that creams containing tretinoin, an acid that rebuilds collagen, may improve the appearance of stretch marks that are less than six weeks old and still pink in color [source: Mayo Clinic]. If you're serious about banishing your stretch marks, you may want to look into stronger treatments like dermabrasion, chemical peels and laser treatment -- but always talk to your doctor first.

If you're looking to get a summer glow without exposing yourself to the sun's harmful UV rays, there are also skin-darkening moisturizers. These lotions give skin just a hint of color with the first use, and the color increases gradually with each application. The active ingredient usually found in these moisturizers is dihydroxyacetone, also known as DHA. It's a colorless chemical that produces a brown tone when it reacts with amino acids on the outermost layer of the skin [source: Mann]. Because skin is constantly shedding dead cells on the skin's surface, the color lasts about five days. Erythrulose is a skin-darkening ingredient that's often used as an alternative to DHA -- DHA can give skin an orange tint -- but DHA is the only FDA-approved sunless tanning ingredient. [source: Mayo Clinic].

Check out the links on the following page for more information on skin moisturizers.