What are ingredients to look for in a cleanser?

The key to choosing the best cleanser for your skin is understanding what certain soap ingredients do. Most soaps contain the following ingredients: detergents, moisturizers, fragrances and preservatives [source: Draelos]. Detergents are designed to remove dirt and oil from the skin. Moisturizers lubricate the skin and help it retain moisture, and humectants, such as glycerin, attract water into the epidermis -- making skin soft and supple. Fragrances give the soap -- and your body -- a scent, and preservatives prevent bacteria growth [source: New Zealand Dermatological Society].

Soap's main purpose is to remove dirt and bacteria from your skin, which is why soaps contain cleansing agents called surface-active agents or surfactants. Nonionic surfactants -- such as polyethylene glycols and acyl-polyglycoside -- and silicone surfactants are gentle detergents that help skin retain moisture [source: New Zealand Dermatological Society]. Syndets, synthetic cleaning agents, are another beneficial soap ingredient. They contain chemicals such as sulphur trioxide, sulphuric acid and ethylene oxide, which are gentle on sensitive skin. These soaps often have added lanolin and paraffin -- moisturizers that can benefit dry skin [source: New Zealand Dermatological Society].

If you're concerned about body odor, look for deodorant soaps that contain antiseptics and disinfectants -- such as triclosan and parachlorometaxylenol -- that can help reduce bacteria [source: New Zealand Dermatological Society]. Acne-prone skin can benefit from cleansers that contain benzoyl peroxide and salicylic acid -- these ingredients gently exfoliate the skin's surface and remove oil that can clog pores and cause pimples [source: Web MD]. If you need a cleanser that can reduce fine lines and wrinkles, look for products with antioxidants, alpha-hydroxy acids, retinoids or vitamin C [source: Bruno].

Using a cleanser that contains the right ingredients can bring out the best in your skin; however, when you wash with the wrong cleanser in the wrong place, you could irritate your skin. Keep reading to find out which ingredients to avoid.

Harsh soap has long been the culprit of dry, irritated skin -- many soaps contain strong ingredients that are far from skin-friendly -- but knowing which cleanser ingredients to avoid can help prevent skin irritation.

Steer clear of soaps that list anionic surfactants as ingredients -- they contain carboxylate, sulfonate and sulfate ions that can severely irritate skin [source: Skin Care Guide]. And if you have dry or sensitive skin, avoid cleansers that contain sodium lauryl sulfate -- this common soap ingredient can cause dry, flaky skin [source: Bruno]. Medicated soaps that help fight acne or treat body odor often contain benzoyl peroxide, sulfur or resorcinol antibacterials like triclocarban and triclosan. These ingredients can cause skin irritation, so don't use cleansers that contain them unless you have oily or acne-prone skin [source: Draelos].

In addition to causing dry, irritated skin, some soap ingredients can also cause allergic reactions. Some common offenders include chamomile, preservatives such as quaternium-15, and fragrances [source: New Zealand Dermatological Society]. Fragrances are found in most skin care products and are the ingredients that are most likely to elicit an allergic reaction. If scented products irritate your skin, look for products labeled "fragrance free" or "without perfume" [source: American Academy of Dermatology].

For more information on cleanser ingredients and how they affect your skin, take a look at the links on the following page.