Cleanser and Soap Basics: Why Cleanse?

Why Cleanse the Skin?

Skin cleansing is necessary for skin health, hygiene and well being. Without effective cleansing, your skin’s surface can accumulate debris, sweat, air pollution, excess oil and bacteria. Cleaning the skin also helps to reduce the growth of microorganisms and reduce infection.

Washing with water alone will rinse some of the dirt and debris away, alone it’s not quite enough. Plain tap water will only remove about 65 percent of the oil and dirt on your skin, and will not effectively remove makeup. Skin cleansers, however, work as emulsifiers and help remove dirt, excess sebum (natural skin oils), bacteria, cosmetics and exfoliated surface skin cells.

Cleansers are especially important for those who use cosmetics, have sensitive or irritated skin, or use topical skin treatments.

Where Dirt and Debris Collect

When we cleanse our skin, we’re targeting the outermost layer of the skin called the epidermis. This outermost layer of the epidermis is composed of a tough protein-fat structure that produces a protective outer film, the skin moisture barrier. Part of the function of the epidermis is to waterproof the skin. While this film shields skin cells from the environment, it also traps and holds dust, pollutants, smoke, bacteria, cell debris, sweat and cosmetics.

Washing the embedded dirt off of your skin also removes some of this outer protective film and can irritate your skin, although mild cleansers have been developed to restore and maintain this protective covering.

The Disadvantages of Soap

Soap is the simplest type of surface-active agent - surfactant - and works by making fat and oil water-soluble and easily removed by wiping or washing. Made from fatty acid salts, soaps clean by reducing the surface tension of your skin with anionic agents such as carboxylate, sulfonate and sulfate ions which are potenial irritants.

At one time, it was thought soaps caused irritation by removing only fat from the outermost layer of the skin, but research indicates that soaps damage affects both the fat and protein structures of this top layer. This can cause unpleasant skin reactions and lead to a rougher skin texture. More bad news: the soap salts that emulsify dirt and oil are by nature alkaline and will raise the skin’s acidic pH as well as provoke swelling of the skin surface. Some studies have shown long-term use of a neutral or alkaline surfactant, such as soap, can increase the amount of bacteria on the skin, while swelling can lead to cellular damage or even breakage. Soap salts can also remove natural moisturizing factors and disrupt the skin’s protective barrier. The fatty acids in soap can have harmful effects too, by plugging follicles (pores) and causing acne.

Soaps may also contain fragrance (often to mask the strong odours of surfactants) and sometimes dyes or pigments. These ingredients can be irritating for people with sensitive skin.

Cleansing History

Today many people use the term “soap” to refer to any cleaning agent regardless of its chemistry. Traditionally soap is a simple combination of fats, oils and salt with a history stretching back to the ancient Romans. In fact, the word “detergent” is derived from “to wipe off” in Latin.

Soaps as we know them were first used about 600 BC by the Phoenicians who combined goat fat, water and potassium carbonate ash to form a solid soap.

More recently, in 1878, Harley Procter developed a new type of soap in collaboration with his cousin, James Gamble. They whipped air into a solution and created Ivory Soap, a product still sold today.

How to Cleanse Your Skin

1. Technique

Most mild, liquid cleansers can be used to clean the whole body, and some can be used without water. Lightly rub the cleanser over your skin to loosen cosmetics, debris and dirt, then rinse well with warm water or wipe off the excess with a clean dry cloth/tissue. Those with very sensitive skin should take special care to remove all the cleanser, as some ingredients could be irritating if left on the skin.

2. Frequency

Mild cleansers can be used once or twice a day on sensitive skin, depending on your preference and your doctor’s advice.

3. Moisturizers

Humans have moisturized their skin for thousands of years, and for good reason. Moisturizers increase the hydration of your skin by trapping and holding water as well as helping maintain and repair the skin barrier. Moisturizers also play a role in preventing contact dermatitis and can soothe inflammation in damaged or irritated skin. Avoid using too rich moisturizers, however, as these can lead to breakouts.

Skin Cleansers Aid Sensitive Skin

Skin cleansers may be an important adjunct to the regimen of those who use cosmetics, have sensitive or compromised skin, or utilize topical therapies. Cleansers emulsify dirt, oil and microorganisms on the skin surface so that they can be easily removed. During cleansing, there is a complex interaction between the cleanser, the moisture skin barrier, and skin pH. Cleansing, with water, soap or a liquid cleanser, will affect the moisture skin barrier. Soap will bring about the greatest changes to the barrier and increase skin pH. Liquid facial cleansers are gentler, effecting less disruption of the barrier, with minimal change to skin pH, and can provide people with a cleanser that is a combination of surfactant classes, moisturizers and acidic pH in order to minimize disruption to the skin barrier.

Skin cleansers are surface-active substances (i.e., emulsifiers/detergents/surfactants/soaps) that lower the surface tension on the skin and remove dirt, sebum, microorganisms and exfoliated corneum cells in an emulsified form. The ideal cleanser should do this without irritating, damaging or disrupting the skin and the moisture skin barrier. Water alone removes approximately 65% of oil and dirt from the skin, but is less effective at removing oils of cosmetic import and some environmental insults. Soaps are the oldest surfactants, and are chemically defined as the alkali salt of fatty acids with a pH of 9.5-10. Synthetic detergents vary in composition and surfactant types (i.e., anionic, amphoteric, cationic, non-ionic, and silicone) and pH. In modern usage, the term “soap” generally refers to any cleansing agent regardless of chemistry.1

Skin cleansers consist of the following:
• Water
• Surfactants (to emulsify the debris)
• Moisturizers (to hydrate the skin and maintain the skin barrier)
• Binders (to stabilize the formulation)
• Lather enhancers (found in some products)
• Fillers (generally used to harden bar soaps and cleansers)
• Preservatives (to prevent the growth of microorganisms)
• Fragrance (generally used to mask the odour of surfactants)
• Dyes or pigments (found in some products)

Skin cleansing may disrupt or disturb the moisture skin barrier, affect the skin surface pH, and irritate the skin. The moisture skin barrier protects against transepidermal water loss, chemical insult and xenobiotic penetration while preserving water to moisturize and maintain the smoothness and flexibility of the skin. A compromised barrier has been correlated with psoriasis, ichthyoses, and atopic dermatitis.2 Moisturizers, both emollients and humectants, within cleansers can maintain skin hydration as well as maintaining and restoring barrier function.3 Emollients impair evaporation of skin moisture by forming a film on the skin surface to impede water loss. Humectants attract and bind water, drawing it up from the dermis into the epidermis. The acid mantle of the skin plays an integral role in skin barrier function as well as regulating bacterial flora.4 Studies have shown that skin barrier regeneration/repair proceeds more slowly at neutral pH (7.2) than at physiological pH 5.5.5 Cleansers may also cause irritant or allergic contact dermatitis and this effect is enhanced if the skin barrier is compromised.

Conclusion

The choice of facial cleanser is important for people with normal skin, as well as for those people with sensitive skin and skin diseases such as atopic dermatitis, acne vulgaris. Liquid facial cleansers are the best choice for facial cleansing as they have an acidic pH, moisturizers and high rinsibility. Within the liquid cleanser category, the least irritating cleanser will contain non-ionic/silicone-based surfactants combined with moisturizers, as they will cause the least disruption to the moisture skin barrier and the normal skin flora.

B. L. Kuehl, PhD1 , K. S. Fyfe, H BBA2, N. H. Shear, MD, FRCPC3

1Scientific Insights Consulting Group, Mississauga, Ontario Canada
2GlaxoSmithKline, Consumer Healthcare, Oakville, Ontario Canada
3Departments of Medicine (Divisions of Dermatology and Clinical Pharmacology), and Pharmacology, University of Toronto Medical School; and Division of Dermatology, Sunnybrook & Women’s College Health Sciences Centre, Toronto, Ontario, Canada