Surfactant and Cleansers 101

Finding your go to cleanser or shampoo may be the best thing you can do for your skin & hair routine. It all starts with the surfactant lying in your cleansing products to give your skin & hair a blank canvas after everything it’s gone through during the day.

Surfactants in your cleansing products work by picking up the excess oil & grime from your day, and then it rinses off with the addition of water.

Types of Surfactants

  • Cationic – positively charged head group
  • Non-ionic – no charge head group
  • Anionic – negatively charged head group
  • Amphoteric – simultaneously carries both anionic and cationic hydrophilic head group

Examples of Common Surfactants & What You Should Know

Sodium Lauryl Sulfate (SLS): an anionic surfactant that has high foam & cleansing properties. It is generally very cheap & easy to source, which makes it a popular choice to use as a surfactant. It has been shown to cause irritation & may not be the best choice for people with sensitive skin or scalps.

Sodium Laureth Sulfate (SLES): is the ethoxylated version of SLS, so it’s SLS but with a few more oxygens inserted. It’s considered more mild than SLS because of the ethoxylation — it’s more water soluble, and therefore, more mild & less irritating.

SODIUM versus AMMONIUM Lauryl/Laureth Sulfate?: The cleansing portion of the surfactant is the Lauryl/Laureth Sulfate part & not the sodium or ammonium part. Those are just the ions making the charged head group of the surfactant. If you come across a product that markets itself to be SL(E)S free, make sure you check the ingredients list because they might be using AL(E)S instead. They think they’re slick, but you are a Cosmetic Padacts blog reader & you are smarter than them!

Fatty Acids + Base: The saponification of fatty acids + base typically yield a higher pH, so if you have dry or sensitive skin, I definitely would not recommend using a cleanser with this combination. However, this combination yields great foam & cleansing properties. Saponification has been done for many decades & is something that you’ll briefly learn about in science class.

  • Fatty Acid examples: stearic acid, Palmitic Acid, myristic acid
  • Base examples: potassium hydroxide, sodium hydroxide, triethanolamine

(Refer to Science of Beauty — The Basics: Science of Skin for a refresher on skin chemistry).

Cocamidopropyl Betaine: an amphoteric surfactant that has excellent foaming, cleansing properties, and stability. It is typically used as a co-surfactant & can decrease the irritation level of anionic surfactants on the skin. It can also be sourced from coconuts 🥥.

Sodium C14-16 Olefin Sulfonate: an anionic surfactant that is typically used in sulfate-free cleansing products. It is mild, offers high foam, and has excellent cleansing properties. It is more expensive than sulfate-based surfactants but is definitely still on the cheaper side of surfactants.

Sodium Cocoyl Isethionate: one of my favorite sulfate-free surfactants — an anionic surfactant made from the fatty acid of coconut oil 🥥 . It has excellent moisturizing properties & is mild to use. It is typically seen in combination with other surfactants, foam boosters, or viscosity increasing agents to meet the aesthetic that consumers are looking for.

(Di)Sodium Cocoyl Glutamate: one of my favorite “natural” & mild surfactants that I look for in cleansing products. It is typically used in combination with other surfactants for foam & product viscosity but can also offer great foam on its own. However, it may be difficult to formulate with due to reduced solubility in water — just the typical issues you can come across when formulating sulfate-free products.

Why are most surfactants in my cleansing products anionic?

Cationic surfactants adsorb strongly to negatively charged surfaces; therefore, they are not efficiently removed when rinsing. Anionic surfactants typically have great foam & consumers link foam to how efficacious a product can cleanse. Also, think about how like dissolves like — negative charge with negative charge will result in better rinsing.

The issue that arises is irritation with anionic surfactants. As with all surfactants, there will be some form of irritation because you are removing oil & sebum (excess or non-excess). This can be combatted with the combination of anionic surfactants with amphoteric or non-ionic surfactants or the addition of conditioning & moisturizing agents.

What do I look for in a shampoo or cleanser?

You should know by now that I am an avid ingredients list reader. I will stand in the aisle and decode the ingredients list before I decide to buy a product. Whether it’s a cleanser or a shampoo, I always look for the surfactant that is used & for any conditioning or moisturizing agents that will offset any possible irritation. Therefore, I don’t mind using cleansing products with sulfate surfactants, so long as it has ingredients that will condition or moisturize my skin and hair.

Shampoo

For shampoos, I do lean towards sulfate-free surfactant shampoos because it is more mild on my scalp & hair. I also look for shampoos with polyquaterniums & anything hydrolyzed — like hydrolyzed keratin or protein.

  • Polyquaterniums are cationic polymers that act as conditioning agents. They’ll help in combability of hair and add gloss & shine.
  • Hydrolyzed keratin or protein will moisturize & strengthen your hair through penetration of your hair cuticle.
  • (Refer to Science of Beauty — The Basics: Science of Hair for a refresher on hair chemistry).
  • Not only am I looking for a nice wash for my hair, I’m looking to repair and strengthen my hair because I honestly do not take care of my hair as much as I should — guilty. If I can’t find a sulfate-free shampoo, I’m fine as long as it has ingredients that will help with irritation.

    Facial Cleanser

    For facial cleansers, I usually don’t experience any irritation when using sulfate-based surfactants or the saponification of fatty acids + base, so I’m typically open to trying new cleansers if my favorite cleanser is unavailable. However, most of the cleansers that I own are all sulfate-free & use a combination of different surfactants.

    I typically look for neat & innovative or convenient texture and component when I’m looking to buy a facial cleanser. Following that, I look for conditioning or moisturizing agents — e.g. humectants, oils, extracts, amino acids, occlusives, etc. to try and combat any possible irritation that may occur with use.

    Whenever I can, I try to check the pH of a product before I use it. However, there are some Korean brands that showcase the pH or pH range of their product as a part of their marketing story — and this is something that I really appreciate because if the pH is slightly acidic, you’ll already feel better about using that product on your skin.

    References & Additional Reading:

    Byrdie – This Is How a Keratin Treatment Changes Your Hair

    NCBI – Patch Testing with SLS to Interpret Weak Reactions to Contact Allergens as Allergic or Irritant

    NCBI – SLS Stimulates the Generation of ROS through Interactions with Cell Membranes

    NCBI – The Effects of Cold Saponification on the Unsaponified Fatty Acid Composition

    Research Gate – Cationic Surfactants & Their Uses in Different Fields

    Contact Dermatitis – Surfactants and Experimental Irritant Contact Dermatitis

    Please look forward to the extension of this post: How do I combat formulating sulfate-free cleansing products?

    Comment below if you found this post helpful or if you have any questions. You can also submit comments/questions through the Contact tab or directly e-mail: cosmeticpadacts@gmail.com.  Thank you for being a part of this journey! – Cosmetic Padacts
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