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Surfactants. Things to know before buying or making solid shampoo bar.

Surfactants. Things to know before buying or making solid shampoo bar.

Solid shampoo is a real alternative to commercial bottled cosmetics. It normally consist of ecological and natural materials and does not include plastic packaging.

Benefits of changing your shampoo to solid one are:

  • They are lightweight and easy to carry. Forget about putting your shampoos in plastic bag for airport control or the ones that explode all over your your clothes in the luggage.
  • They are eco friendly as they do not include any plastic packaging. 
  • They last longer! Most shampoo bars are equivalent of 3 bottles of liquid shampoo! 100 grams of shampoo bar can last few months so at the end they are cheaper too.
  • They are more healthy - most solid shampoo bars do not have hundreds of ingredients and mostly consist of surfactants, natural powders, oils and butters, waters and essential oils.

Whether you want to make your own solid shampoo or buy one, I would like to introduce to you some of the ingredients and properties they bring.

Solid shampoos can be made using 2 different ways:

  • using cold processed technique and basically using same technique for a shampoo making as making a soap bar.
  • using surfactant - they are used to wash the hair and solidify the shampoo.

Most of companies right now are using solid surfactants to produce their solid shampoos and that is the type of shampoo I would like to talk about in Part 1 of shampoo ingredients (I only include those that are used in solid versions).

Primary surfactants


A shampoo is by definition a washing product. Starting from this simple principle, the quality of a shampoo is the surfactants (washing agents) used. There two types of surfactants primary and secondary:

1. Primary surfactants

This is a key ingredient because it will result in the quantity / quality of the shampoo foam and its ability to wash the hair.

Sodium Lauryl SulfateSLS (INCI: sodium Lauryl sulfate) - is a classic anionic surfactant that is considered milder than sodium laureth sulfate (SLES) but has very similar properties. The SLS is derived from coconut and/or palm kernel oil, both of which are rich sources of lauric acid.

SLS is a "moderate hazard" that has been linked to cancer, neurotoxicity, organ toxicity, skin irritation and endocrine disruption. It all depends quantity of it in the product. If you make your own shampoo don't exceed 50% (only applicable for products that have short contact with skin and are rinsed off).

This surfactant is removing hair oils more aggressively therefore not suitable for everyday hair wash and might "dry out" your hair after long use.

Sodium Coco Sulfate - SCS (INCI: sodium coco-sulfate) - is a solid anionic surfactant of coconut origin. It is not the same thing as Sodium Lauryl Sulfate (SLS) and is generally accepted as a gentler alternative.

The difference from SLS lies in the science. The process to make SLS involves a chemical reaction that isolates one fatty acid from either petroleum jelly, coconut oil or palm oil; whereas SCS is derived from a blend of fatty acids from coconut oil.

It is considered to be more mild that SLS.

Sodium Cocoyl Isethionate - SCI (INCI Sodium Cocoyl Isethionate). A surfactant derived from coconut oil. This is one of the mildest surfactant you can find, it does not irritate the scalp.

Derived from the amino acid "Isethionic". The primary surfactant that I place above all others! Well formulated and used as primary surfactant, it gives very soft shampoos, which are suitable for dry hair or with larger amount for greasy hair as well.

Amount of SCI in the recipe: between 30% and 60% of the weight of the preparation. Never exceed 60%. Use less if you have dry hair and more if you have oily hair.

Sodium Lauroyl Methyl Isethionate - SMLI (INCI: Sodium Lauroyl Methyl Isethionate)  the mildest surfactant you can find. A mild anionic surfactant derived from coconut, which does not contain sulphate. Unlike Sodium Cocoyl Isethionate (SCI), which makes it possible to create opaque products, SLMI has excellent solubility in water, and thus makes it possible to create shampoo formulations without sulfate It is often used in conjunction with Cocamidopropyl betaine (secondary surfactant)

2. Secondary Surfactants

They are often amphoteric surfactants, less foaming, less detergent than anionics. But they also have advantages that make them unavoidable, such as the ability to soften an irritating primary surfactant (such as Sodium laureth sulfate).

Betaines and Amphoacetates

(most popular are also the least natural and considered a little more irritating than others)

Cocamidopropyl Betaine (CAPB) / Cocamidopropyl hydroxysultaine (CAHS): The suffix "propyl" denotes a membership in petrochemicals. They must therefore be thoroughly purified (and this is not always the case) to no longer contain irritating residues. It is one of the ingredients that is an exception in the COSMOS specifications: it is authorized in organic. However can cause allergies.

Sodium Cocoamphoacetate / Sodium Lauroamphoacetate: Same properties as the 2 previous ones they are widely used in conventional and organic, since they are also authorized in natural cosmetics certified Ecocert. 

Coco betaine / Lauryl betaine : The same type of secondary surfactant as cocamidopropyl betaine with the same properties, but without the petrochemical part "propyl".


They are not drying and therefore very soft, but without having any conditioning power such as surfactants derived from amino acids. Their foaming power is quite weak.

Decyl Glucoside / Coco Glucoside / Lauryl Glucoside: These are sometimes used as primary surfactants but does not foam and doesn't have a good washing power on very dirty hair or oil baths. 

As surfactants are the base of most of solid shampoos I hope this can help you understand the difference between them and not to forget that most of these are used as a foaming agents but they are not crucial to any shampoo for that matter.

Sodium bicarbonate removes oils very good and it is the most eco friendly version there is but if you have ever tried it, you know that its not the "most" pleasant feeling when standing in the shower and rubbing backing soda on your hair (I did it for few months and will make a blog post about it.)

Other than surfactants we have few more ingredients that makes a good, eco-friendly, zero waste and personalized solid shampoo bar so stay tuned for next blog post about  other solid shampoo ingredients.

SCS (50%) foaming after 2sec rubbing  SLMI (35%) foaming after 2sec of rubbing 



Till next time loves,

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