If you’re looking for a safe and vegan shampoo or cleansing bar with essential oils, then you must look for a bar that contains Sodium Cocoyl Isethionate (SCI) as its surfactant. Essential oils are derived from botanicals while SCI is processed but coconut derived. Moreover, SCI is mild scented hence does not overpower the fragrance of essential oils. It can blend oils and water along with other ingredients well because it has an emulsifying property. (1)
Blast from the past
Unlike other ingredients such as lye which has been used hundreds of years ago, the use of SCI has not been reported for hair or skin cleansing preparations until after 1984. However, in 1992 it has been documented that SCI was included in 52 cosmetic products. (2)
Since its development, its been widely used especially for mild cleansing products that are catered to health-conscious consumers. Due to its mildness it is even termed as ‘baby foam’ (1) It’s one of the favorite plant-derived surfactants because when used for cleansing bars it serves not only as a cleanser, foaming agent, and emollient. It also functions as a conditioner, softener, and moisturizer (1)
Other names
While this anionic surfactant may sound like a new term to you, you may have probably used it or read it from the labels of your cleansing products. Other names for this surfactant are coconut fatty acid, 2-sulfoethyl ester, sodium salt, fatty acids, coconut oil, sulfoethyl esters, sodium salts; Igepon AC-78, and Jordan CI. (2)
Physical and Chemical Properties
SCI is composed of both active ingredients and minor impurities (2) It has isethionic acid which is sulphonic acid. It also has fatty acid or sodium salt esters that are derived from coconut oil. (1) Hence the name Sodium Cocoyl Isethionate. SCI forms when sodium isethionate reacts with coconut oil’s fatty acid mixture or chlorides. Initially, it’s prepared by adding ethylene oxide to sodium bisulfite. (2)
Safety and toxicity
SCI is said to be nontoxic or almost completely toxic-free. (2) Moreover it is not a phototoxic or a sensitizer. A concentration test conducted by some researchers revealed that SCI is safe to be used as a cosmetic ingredient if it’s used at 50% in rinse-off products and 17% in leave-on products. (2)
Skin-friendly properties
1. Gentle to the skin
Due to its mildness, it is suited for babies with delicate skin as well as those who have sensitive skin that needs mild soap. A possible explanation for this mildness was presented by an in vitro study in 2007. The researchers of the study concluded that the mildness of SCI is due to the inability of the SCI micelles to penetrate the stratum corneum (SC) through the smaller aqueous pores, hence it cannot induce skin barrier perturbation. The size of the SCI micelles and aqueous pores matters. Simply explained, the smaller the micelles are produced by the surfactant the easier it can penetrate through the aqueous pores. Due to the size of the micelles that SCI forms, it cannot easily penetrate the skin. The larger the micelles the SCI produces makes, prevents it from penetrating smaller aqueous pores. SCI micelle with a radius of 33.5 +/- 1 Angstrom cannot penetrate the stratum corneum (SC) through the aqueous pores that have a radius of 29 +/- 5 Angstrom. (6)
2. Conditioning effect
This gentle plant-derived surfactant has a onditioning effect thus making your skin feel hydrated, soft, silkier, and smooth. (1)
3. Mild pH
Although the skin can balance it’s pH, using cleansing bars with SCI prevents our skin from overworking balancing acid and alkaline. SCI has a mild PH of around 5 to 6. (4) while another source noted an exact PH level of 5.5 (5). SCI is also said to be stable at a pH level of 6-8 however, it hydrolyzes thus becomes unstable if it’s not within this pH range (2)
4. Smoothly cleanses the skin
There are several reasons why it’s good cleansing agent. SCI has a good foaming capacity that allows it to produce foamy and ‘creamy dense’ bubbles. (7) On top of that its emulsifying property not only blends oil and water, but it also encourages dirt to stick with it, thus making it easier for flushing out the dirt. (1)
5. Nonmutagenic
SCI is found to be nonmutagenic and did not demonstrate a positive reaction in an S. Typhimurium preincubation reverse mutation assay. (2)
Opt for cleansers that spares you from worrying about toxic ingredients. If you look for vegan, not harmful to the environment plus good for your skin, then a cleansing bar or a cosmetic product with this ingredient is a recommended one.
Happy cleansing 💋❤
References:
- New Directions Aromatics. Sodium Cocoyl Isethionate. https://www.newdirectionsaromatics.com/blog/products/all-about-sodium-cocoyl-isethionate.amp
- Cosmetic Ingredient Review. Final Report on the Safety Assessment of Sodium Cocoyl Isethionate. Journal Of The American College Of Toxicology. 12(5).1993.Mary Ann Liebert, Inc., Publishers
- Humble bee and me. Sodium Cocoyl Isethionate. https://www.humblebeeandme.com/project/sodium-cocoyl-isethionate/#:~:text=Sodium%20Cocoyl%20Isethionate%20(SCI)%20is,cleansers%20and%20opaque%20liquid%20cleansers.
- Savvy Homemade. DIY shampoo bar. https://www.savvyhomemade.com/diy-shampoo-bar/
- Herbal Cochete. Shampoo bar recipe with SCI. https://herbalcochete.com/solid-shampoo-bar-recipe-with-sci/
- Ghosh, S., & Blankschtein, D. (2007). Why is sodium cocoyl isethionate (SCI) mild to the skin barrier? – An in vitro investigation based on the relative sizes of the SCI micelles and the skin aqueous pores. Journal of cosmetic science, 58(3), 229–244.
- Summer rain. How to make a shampoo bar. https://summerrain.website/how-to-make-a-shampoo-bar/?amp
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