Soft surfactants in shampoos

To begin with, we note that the lipid barrier of our skin has a slightly negative charge.
When any surfactant interacts with the epidermis, there is a “swelling” of the stratum corneum and an increase in its permeability to active components. At the same time, this process leads to disruption of the barrier functions of the epidermis. The mechanism of this action is associated with the effect of surfactants on skin lipids.
The irritating effect of surfactants is due to the destruction of proteins and inactivation of enzymes. As a result, the skin feels dry, irritated and red.

Anionic, negatively charged surfactants weakly interact with the surface of the skin (minus and minus, as is known, repel). Therefore, anionic surfactants are dermatologically quite safe for human skin.
Anionic surfactants include sodium lauryl sulfate, ethoxylated sodium, magnesium and ammonium lauryl sulfate, sulfated castor oil - “Turkish red oil”, sodium dodecyl sulfate, TEA Layril Sulfate (TEA lauryl sulfate), TEA Laureth Sulfate (TEA laureth sulfate).

The mechanism of action of anionic detergents is interesting.
The molecule of anionic surfactants contains a water-soluble (hydrophilic) part, which is negatively charged, and a fat-soluble (hydrophobic) part, which is neutral. The fat-soluble part of the molecule binds and envelops dirt particles and sebaceous gland secretions. The water-soluble part of the molecule is oriented away from the hair, which carries a negative charge, as a result of which dirt particles connected to the surfactant are rejected by the hair, dissolved in water and removed.

Cationic, positively charged surfactants form stronger bonds with negatively charged functional groups of proteins, lipids, phospholipids and other compounds of the human lipid biolayer (minus and plus, as is known, attract). Cationic surfactants are used less frequently in cosmetics and mainly in water-rinsed cosmetic products.

Nowadays the demand and need for mild cleansers is increasing, and the requirements for a clean environment are also increasing. All this encourages the search for biodegradable surfactants that are harmless to nature and safely cleanse the human body.

Non-ionic surfactants have less irritating properties.
Non-ionic surfactants include mono and diglyceric fatty acids - often oleic, linoleic, alkyl glycoside (cocoglycoside).

Amphoteric surfactants (capable of carrying both positive and negative charges) have the mildest dermatological effect. They can be used to wash even the smallest children.
Representatives of amphoteric surfactants such as betaines are more often found in detergent compositions.
The first to appear on the market were cocamidopropyl betaine and lauryl sulfobetaine, and later the more effective cocoamphoacetate and cocoamphodiacetate, amidobetaine. The raw materials for the production of such amphoteric surfactants are fatty acids from coconut, sunflower, soybean and rapeseed oils.

In modern cosmetology, combinations of various surfactants are used. In many cases, even small additions of a mild surfactant can cause a very significant improvement in the dermatological properties of the compositions. Some amphoteric surfactants extremely strongly reduce skin irritation caused by contact with anionic surfactants.

The safest surfactants contained in “natural” (organic) cosmetics include:
Decyl Glucoside is a non-ionic surfactant of plant origin, thickener. Used as an additive or co-surfactant in cosmetic cleansers.
Lauryl Glucoside is a surfactant, a foaming element in detergents. Obtained through the process of rectification of fats. Mild surfactant for intimate hygiene products and baby shampoos, gels, bath foam. Increases viscosity. Synthesized from natural raw materials such as coconut oil and glucose.
Sodium Palmate - sodium palmate. Obtained by alkaline hydrolysis of palm oil.
Cocamidopropyl Hydroxysultaine is a fatty acid from coconut oil.
Sodium Cocoamphoacetate is an amphoteric surfactant, a surfactant that enhances foaming and has a mild cleansing effect. An aqueous solution of an amphoteric surfactant obtained from coconut oil fatty acids.
Decyl Polyglucose surfactant - natural from corn starch, wheat grain and coconut
Zea Mays (CORN) - corn silk
Disodium Coco-Glucoside Citrate
Vegetable Decyl Glucoside is a natural cleansing combination (surfactant) of fatty acids from coconut oil and sugars (or carbohydrates) from sugar cane.
Olivoyl Hydrolyzed Wheat Protein - surfactant obtained from olive oil and wheat

Conditionally safe surfactants (during research it was revealed that a substance in high concentration can have an adverse effect on the health of animals (liver; reproductive function; central nervous system; irritation of the skin, mucous membranes)) contained in “natural” (organic) cosmetics include:
Cocos Nucifera (COCONUT) oil - coconut oil
Palmitic Acid - palmitic acid
Sodium Stearate - sodium salt of fatty acid
Disodium Cocoamphodiacetate is an amphoteric gentle surfactant based on coconut oil.

Unsafe surfactants (in high concentrations, carcinogenic, toxic, irritating to the skin and mucous membranes). They have restrictions in use.
Cetrimonium Etrimonium Chloride is a quaternary ammonium salt used as an antiseptic and preservative.
Lauramide DEA is a semi-synthetic chemical used to form foam and thicken various cosmetic preparations. May dry out hair and skin, cause itching and allergic reactions.
PEG-150 Distearate is a polymer derived from ethylene oxide and fatty acids.

Now let's look at an example of a branded cosmetic product Bentley Organic.
Bentley Organic shower gels contain the following surfactants: Potassium Oleate (anionic surfactant), Potassium Cocoate (nonionic surfactant, the result of the interaction of coconut oil with alkali), Lauryl betaine (amphoteric surfactant, antistatic, has a slight conditioning effect), Decyl glucoside (nonionic Surfactant of plant origin, thickener).
Thus, Bentley Organic brand shower gels contain mild detergent components and can be used by people with sensitive skin.

The entire range of SHAMPOOS, incl. and CHILDREN'S SHAMPOO with aloe juice and chamomile, INTIMATE HYGIENE FOAM with chamomile and boswellia

Properly selected and balanced surfactant systems increase the permeability of the stratum corneum for active components that would otherwise remain on the surface of the skin (Margolina, Hernandez. New cosmetology. Vol. 1, 2005)

Golubkov A.S., Gorodnichev B.N., technology department MIRRA

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Maria Fetisova

Surfactants (surfactants) are widely used in cosmetics. Thanks to them, shampoos and shower gels cleanse the skin of dirt, and cosmetic emulsions remain stable and do not break down into an oily aqueous phase. Everything would be fine, but in addition to useful technical qualities, surfactants also have a downside - they can dry and irritate the skin.

1. Surfactants are emulsifiers and cleaning components

Emulsifiers are components that cannot be avoided if a manufacturer wants to create an emulsion consisting of oil and water. Without emulsifiers, it will separate into two phases, and this not only does not look aesthetically pleasing, but also creates a favorable environment for microbes that can settle at the boundary of the water and oil layers. In addition, the nature of the distribution of active components changes, which may even lose their activity.

The most powerful emulsifiers are surfactants (surfactants). Their main task is to break down dirt (fats) during laundry, hair washing, and skin washing. It is surfactants that form foam in cleansing products.

2. Surfactants cleanse skin and hair

Surfactants in soaps, shampoos, and shower gels are absorbed on the surface of contaminants (grease, dirt), embedded in them, crushed into small drops, thus facilitating the removal of these particles. The problem is that surfactants do not see the difference between “unnecessary fats” and the natural fat lubricant of the skin. Therefore, any surfactant that “cleanses well” the skin can make it dry and irritated.

3. Surfactants can irritate the skin

When surfactants get on the skin, the cells of the stratum corneum of the epidermis swell and their permeability to active components increases. On the one hand, the more the stratum corneum swells, the better and faster it cleanses. But on the other hand, at high concentrations, surfactants can damage the lipids of the stratum corneum. In addition, the skin becomes permeable not only to beneficial components, but also to irritating ones - if they suddenly turn out to be part of the product.

4. Surfactants can be obtained from three sources

1. vegetable raw materials (natural origin)
2. from oil and gas (mineral origin)
3. synthesize in the laboratory (synthetic origin)

5. There are different surfactants

Anionic surfactants – one of the most common cleansing components. Cleans well even in hard water. Sodium lauryl and laureth sulfates (SLS, SLES) fall into this category. Currently, the cosmetic industry uses new generation anionic surfactants that do not have the same drying effect as SLS. For example, Sodium Lauroyl Sarcosinate, Sodium Lauroyl Oat Amino Acids.

Cationic surfactants – have a weak cleaning effect, but can irritate the skin more than anionic surfactants. Therefore, they are most often used as a softening additive and to remove static electricity in hair rinse products (Cetrimonium chloride, Quaternium-15)

Amphoteric surfactants – have a mild cleansing effect, reduce the aggressive effects of anionic surfactants, and improve foaming. From the group of amphoteric surfactants, betaine derivatives (cocoaminopropyl betaine) are most often used. Amphoteric surfactants are obtained from fatty acids of coconut, palm kernel, sunflower, soybean and rapeseed oils, as well as hydrolysates of collagen, keratin, elastin and other proteins.

Nonionic surfactants – have a mild irritant effect on the skin, they foam little, so they are often combined with anionic surfactants. They are used in shampoos and conditioners to make hair silky and soft. Nonionic surfactants have the most complete biodegradability (Glyceryl Laurate, Decyl Glucoside)

List of some mild surfactants that are used in natural cosmetics

Coco-Glucoside - Coconut glucoside
A soft foaming substance obtained from dried coconut meat and fruit sugar. Used as a foaming agent, conditioner and emulsifier. In hair products – smoothes the hair structure and adds volume. No side effects of coconut glucoside have been found; it can be used for any skin type and for children's cosmetics.

Lauryl Glucoside
It is synthesized from natural raw materials during the rectification of vegetable fats (coconut oil and glucose). In cosmetics it acts as an emulsifier, dispersant, natural foaming agent, and increases the viscosity of the consistency. It has a mild cleansing effect and is used in children's products and intimate hygiene products. In gels and creams it cleanses and softens the skin; in shampoos it provides a light conditioning effect and makes subsequent hair styling easier.

Sodium Cocoamphoacetate
A surfactant derived from the fatty acids of coconut oil (coconut acid). In cosmetology it is used as a foaming agent and has mild cleaning properties. Creates a pleasant consistency of the product. Typically used as a component for liquid cleansers, gels, and shampoos. In hair products – increases elasticity, improves the structure of damaged hair, and adds shine.

Sodium Cocoyl Glutamate
A surfactant that is a compound of glutamic acid.
In cosmetology it is used as a foaming agent, mild detergent, and emulsifier. Often used in hair washes and shampoos, it creates a feeling of softness, moisturization of the skin, and has a conditioning effect.

Sodium Lauroyl Sarcosinate
Derived from sarcosine, a natural amino acid found in vegetables and fruits.
In cosmetics it is often used as a soft foaming agent, surfactant, and conditioner. A gentle cleanser that is safe for the skin, while at the same time effectively removing dirt, bacteria, and sebum. Does not irritate even sensitive skin. When used for hair care, it returns vitality and shine to it, carefully cleansing and improving its structure.

Sodium Lauryl Glucose Carboxylate
A natural alternative to aggressive surfactants. A very soft natural foaming agent that creates a homogeneous consistency of the product, obtained by reacting coconut and palm oil with sugar and starch. In cosmetics, it is usually used in products for washing and cleansing the skin, and in hair shampoos. No negative or allergic reactions were detected when using this substance.

Sucrose Cocoate
A natural substance obtained from the fatty acids of coconut oil and sucrose ester. The finished liquid has a viscous consistency and light yellow color, and has pronounced moisturizing and softening properties. Sucrose cocoate absorbs water and, when applied to the skin, maintains an optimal level of moisture in it.
Often used in cleansers (gels, foams, makeup remover milk) and moisturizers.