Surfactants and the Skin

When a cleanser, or any other surfactant product, is rinsed from the skin, slight deposits of surfactant tend to remain. Even some of the less aggressive surfactants can cause a temporary disruption of the keratin protein, eventually leading to increased water loss from the stratum corneum. Repeated surfactant exposure leads to increased water loss. Some surfactants can also damage the lipid structures or even strip them out. This also interferes with the barrier function of the skin so that significant amounts of water may be lost, and the skin can become dry and even flaky.

People with sensitive, type I skins are particularly vulnerable to irritation by harsh surfactants, particularly around the delicate skin of the eyes.  

People like this, who have sensitive type I skins, may be particularly vulnerable to skin irritations to surfactants.

Personal cleansing products are now formulated by leading cosmetic manufacturers to be mild but still effective. They are provided in forms that can be used at the sink or in the shower, and often incorporate moisturising ingredients that are deposited on the skin while showering.

Modern skin care products combine gentle cleansing agents (syndets) with moisturising ingredients. Application in the shower using a 'puff' has a mildly exfoliating action and forms an increasing part of body care for many people.

Skin care cosmetic ingredients dictionary

INCI name Function Water Solvent Sodium laureth sulfate Mild cleansing and lathering Glycine soja Moisturizer/occlusive Sodium lauroamphoacetate Mild cleansing and lathering PEG-6 caprylic/capric glycerides Moisturizer/emollient Palm kernel acid Thickener/skin conditioner Magnesium sulfate Thickener Glycerin Moisturizer/humectant Cocamide MEA Mild cleansing and lathering Citric acid Adjusts pH Maleated soybean oil Moisturizer/emollient/occlusive Fragrance Fragrance Polyquaternium-10 Skin conditioner and emollient Disodium EDTA Chelator Sodium benzoate Preservative DMDM hydantoin Preservative

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Typical formulation of a cleanser with moisturising ingredients. The use by consumers of this kind of product in the shower is increasing.

Measuring the mildness of cleansers

A recognised method of assessing whether a product will irritate the skin is the Forearm Controlled Application Test (FCAT). 

This involves using an exaggerated washing procedure to measure irritation for five consecutive days. The dryness and/or redness of the skin is recorded on day 1, using a standardised scale, and again on day 5. Measurements of skin hydration are taken at the same time.

The results can be compared with the results for a known mild surfactant product.