Surfactants In Skincare

Since I became an esthetician, I've often heard the phrase, "SLS is the devil." It's an evil cleansing ingredient that will irritate your skin barrier and cause dehydration and redness. Stay away at all costs.

The surfactant(s) used in a cleanser formulation are an important contribution toward how the cleanser will perform and how stripping it will be to the skin. Let's figure out exactly what a surfactant is, how they work, different groups and examples of them, and if SLS deserves all of the negative attention it receives.

What are surfactants?

A surfactant is a substance that lowers the surface tension of a liquid when added, which enhances its ability to spread and wet surfaces. For the purpose of this article, we are going to discuss surfactants within cleansers.

Surfactants are the base of almost every cleanser on the market. They allow us to cleanse dirt, sweat, and debris off of our skin. Surfactants mix with water and fat to trap debris and other undesirable particles. Once trapped, the water, oil, and unwanted debris wash off of our skin and disappear down the drain.

A surfactant is a molecule with two halves: a hydrophilic (loves water, hates oil) head and a hydrophobic (loves oil, hates water) tail.

In this visual you can see how the oil loving tails are encapsalating the oil droplet and you can imagine the water loving heads living their best life being surrounded by water.

How do surfactants work?

-Oil and water repel each other-

-Oil is non-polar. Water is polar-

-When you add surfactants into oil and water, something crazy happens...-

-...They get along great and become an emulsion-

-An emulsion is a solution of 2 liquids that normally don't mix-

-The surfactants break oil up into droplets within the water so you can wash your face effectively-

Functions of Surfactants (different surfactants serve different functions):

Emulsification: Blending (emulsifying) two unblendable ingredients like oil and water for products such as creams and moisturizers.

Foaming:

Gives user ease that the product is working.

Deep cleaning:

As specified above, the ability for oil and water to work together in order to remove dirt and debris.

Solubilization:

Allows oils and fragrances to disperse evenly throughout a product.

Conditioning:

Leaves skin feeling smooth and softened.

Stabilizes

Improves texture and viscosity of products.

There are 4 groups of surfactants:

Anionic
- Molecules that have a positive charge
- Useful for foaming and deep cleansing
- Often combined with amphoteric surfactant to make less irritating
- Relatively inexpensive
- Examples:
  - Carboxylic Acid
    - Stearic Acid
  - Sulfates
    - Sodium Lauryl Sulfate (SLS)
    - Ammonium Lauryl Sulfate (ALS)
    - Sodium Laureth Sulfate (SLES)
  - Sulfonic Acids (more mild than sulfates but more expensive)
    - Taurates
    - Isethionates
    - Olefin Sulfonates
    - Sulfosuccinates

Cationic
- Molecules that have a positive charge
- Not used in cleansers because they don't cleanse, rinse, or foam well
- More irritating
- Not compatible with anionic surfactants
- Used for conditioning (for example hair conditioners)

Amphoteric (Zwitterionic)
- Molecules that can have positive or negative charge depending on the pH
- Primarily used in skincare as secondary surfactants
- Have ok cleansing properties, but less irritating then anionic surfactants
- Can help increase foaming, conditioning, and reduce irritation
- Make foam bubbles smaller and feel creamier
- Don't function well as emulsifiers
- More expensive
- Examples:
  - Sodium Lauriminodipropionate
  - Disodium Lauroamphodiacetate
  - Cocoamphopropionate
  - Cocamidopropyl Betaine
Non-Ionic
- Molecules that do not have a charge
- Often used as emulsifiers, conditioning agents, and solubilizing agents
- Used in gentle cleansers such as baby shampoos, aren't the best at cleansing
- Non-foaming and often used with anionic surfactants
- Good for solubilizing fragrances and natural oils in formulations
- Second most commonly used surfactant
- More expensive
- Examples:
  - Cetyl Alcohol
  - Stearyl Alcohol
  - Polysorbate Esthers
  - Cocamidopropylamine Oxide
  - Stearamine Oxide
  - Lauramine Oxide
  - Lauramide Diethanolamine (DEA)
  - Cocamide DEA

Examples of Surfactants:

SLS/SLES (Sodium Lauryl Sulfate/Sodium Laureth Sulfate)
- harsh on skin
- known to cause dehydration & redness
- to combat this, often combined with amphoteric and non-ionic surfactants

Sodium Coco-Sulfate (SCS)
- similar to SLS, but much less aggressive
- anionic surfactant
- found in skincare products targeted for oily skin

Cetrimonium Chloride
- cationic surfactant
- has antiseptic properties
- used as conditioning ingredient for skin
- can be combined with anionic surfactants
- can be toxic is high concentrations, but ok in low concentration for rinse-off products

Cocomide DEA, Lauramide DEA, Linoleamide DEA, Oleamide DEA
- non-ionic surfactants
- obtained from natural fatty acids
- Cocomide DEA is derived from coconuts
- Lauramide DEA is derived from lauric acid (considered harshest out of 4)
- Linoleamide DEA is derived from linoleic acid
- Oleamide DEA is derived from oleic acid

Decyl Glucoside
- mild, non-ionic surfactant
- derived from raw plant materials
- added as secondary surfactant and as thickener
- considered one of the "safest" surfactants

Lauryl Glucoside
- mild, non-ionic surfactant
- derived from coconut or palm kernal oil and glucose
- used as mild cleansing agent and thickener

Coco Glucoside
- mild, non-ionic surfactant
- derived from coconut oil or meat of ripe coconuts and grape sugar
- extremely gentle
- suitable for all skin types

Cocomidopropyl Betaine
- amphoteric surfactant
- used as additional surfactant in foaming products in acidic, neural, and highly alkaline formulations
- increases viscosity of formulas and acts as stabilizer and foaming regulator
- safe and mild surfactant

My Favorite Facial Cleansers

Vitamin C Cleanser from GlyMed+