Thursday, August 27, 2015

Designing your products as a line: Shampoo - what's in it? Surfactants

In yesterday's post, Shampoo - how does it work?, we took a look at how a shampoo works to clean our hair. Today, let's take a look at how one would formulate a shampoo, then at the ingredients we might find in one.

So what makes a shampoo a shampoo? We want to formulate a shampoo that will remove sebum and soil from our hair and scalp, remove residue of styling products, leave hair in good condition, and deposit lovely things like panthenol, conditioning agents, and so on.

How do we achieve these goals? We want to include between 15% to 40% surfactants in our mix to remove soil, sebum, and styling product residue. To leave hair in good condition, we'll choose a surfactant mix that is mild to hair and scalp as well as add a few things that might help leave our hair conditioned. And we can use all kinds of lovely ingredients like conditioning agents, panthenol, extracts, and so on to make our hair feel nice when we've rinsed it off.

The concentration of your surfactants will vary, but I usually go for the higher amount (around 40%) because not only is it easier to thicken higher amounts of surfactants, but it's more concentrated, so I don't have to use a lot to get some serious lather!

A basic shampoo would look something like this...

BASIC SHAMPOO
15% to 40% surfactants (mix of anionic and cocamidopropyl betaine)
0.5% to 1% preservative
1% fragrance or essential oil
up to 3% Crothix (liquid) to thicken or use salt at up to 3%
water to 100%

Why are we including each ingredient?

Water: Well, that's a given right? We need to include water in a shampoo to decrease the concentration of the surfactants and act as a solvent for the other ingredients.

Surfactants: We always want to include cocamidopropyl betaine in our mixtures to increase the mildness and thickening of the mix. We can choose surfactants suitable for our skin types - dry, normal, and oily - and use those for our hair types. Some good choices might be...

Dry hair: Amide ether sulfatestauratesSCI (with stearic acid), decyl glucosideacyl glutamate.
Oily hair: Sulfosuccinatesalkane sulfonates.
Normal hair: Whatever you like, lucky you!

All hair types might like the carboxylates (mild cleansing, conditioned feel), SLeS or ALeS, and SCI (without stearic acid for normal to oily hair, with stearic acid for dry hair).

Thickeners: You can use something like Crothix - which will thicken and increase mildness - or salt. (Click here for three posts on increasing viscosity in surfactant mixtures).

Preservative: I generally use liquid Germall Plus in my shampoos up to 0.5%, but you can choose another suitable preservative.

So yeah, I guess we have achieved our goals. Hmm, why do I feel strangely unfulfilled? Perhaps it's because I've left out all the good things that will really make our hair feel really conditioned and soft!

An aside...We could get away without using thickeners in our surfactant mixes - it's really only there for the aesthetics, but a thicker shampoo means less wasted product and will make us think it's more cleansing. Something like glycol distearate (EZ Pearl) is almost always used in shampoo for dry hair because we perceive a pearlized product as more creamy and, therefore, more moisturizing (which it is, actually). Doesn't this picture look like it should be a shampoo for dry hair? (It is, in fact, a bubble bath, but the point is made...)

We don't need to fragrance or colour our shampoo, but there's something about a yellow shampoo scented with citrus that makes us think of refreshing morning showers, a pink shampoo with Pink Sugar that makes us think we're being girly and fun, or a brown shampoo with Vanilla Oak that makes us feel manly and clean. 

I think this basic recipe is a good start - and a great place to start learning about making a shampoo - but what takes a shampoo from okay to awesome are those film forming, moisturizing, and conditioning ingredients. Join me tomorrow as we take a look at those ingredients.

Related posts:
Formulating a basic shampoo

4 comments:

Bunny said...

I actually tried salt to thicken my last batch of shampoo-- it was just SCI and polylactylate blend because I have no coco betaine-- and 2% turned it almost into a gel! So salt is another really easy option if you're careful how much you add! :)

Elisabeth said...

Does salt do anything more for your shampoo other than acting as a thickener? I come from a family with atopic skins, and we've all sworn by the effect of Mediterranean holidays with lots of sun and sea water. I've been using glucosides mostly, so I've never used salt as a thickening agent, but it'd be neat if a concentration of 2% NaCl would be enough to get something of a healing effect going.

Deirdre Saoirse Moen said...

I have to admit that, being allergic to coconut, just reading this recipe made me itch given all the coconut ingredients.

Part of the reason I've been reading your blog is trying to jump into making a coconut-free eye cream.

Baby Kat said...

Awesome post! It's great to have a basic formula to start experimenting and then go on from there. Thanks.