How to Formulate a Solid Shampoo

Hello everyone! 🙂

Today I talk about how to formulate a Solid Shampoo.

Solid Shampoo (10)

This is NOT a natural soap, it is a Syndet (synthetic detergent) made with powder surfactants and other ingredients. A normal soap won’t work well as a shampoo, no matter how many expensive oils you add to it or how much love you put into soap-making.
If you want to make a decent solid shampoo, it must be a syndet. 😉

The advantages of a shampoo bar are that it is compact, it doesn’t weight much, it is easy to use, easy to carry around (on a plane for example)… Yet, it is not at all common to find one in the stores.

The reasons for this are many but here are the main ones:
A Solid Shampoo is made with an extremely high percentage of surfactant matter (55%-85%) and this makes the production costs fly very high as well.
But this is not all: a shampoo bar looks extremely similar to a simple and cheap soap and therefore people don’t give to it even the same value they give to, let’s say, a fancy bottle of liquid shampoo (even if the liquid shampoo costs way less, to produce, than the solid one).
These two things, combined, already don’t make for a winning product…

But this is not all: as you know from the various posts about formulating detergents (you can find them HERE) such concentration of surfactant matter is extremely high and this doesn’t just make the production costs go wild, but it is also an issue for the formulator: a product with 60% Active Surfactant Matter can be very easily too aggressive.

So now that we know the challenge, let’s attempt to formulate a Solid Shampoo!
First of all we need powder surfactants: most of the recipes I have seen around as well as the only solid shampoo I have bought in my life, were made of a single surfactant. However, as you well know, surfactants need to be mixed together in order to give a milder result (and this is something we ABSOLUTELY need in such a product).
So, rule #1: create a mixture of surfactants.

Simply mixing compatible surfactants won’t still make the shampoo mild enough, so a good idea is to add incompatible surfactants: anionics + cationics.
They both won’t work at their best, which is quite a waste, but in the case of a solid shampoo bar it is really needed.
You could use, for example, BTMS or (like I did in this recipe) Behentrimonium Chloride. Avoid the liquid ones (like Cetrimonium Chloride) because you need the solid shampoo to be… well, solid! 🙂

You will need to add a thickening ingredient in order to be sure your shampoo bar will be actually “solid”: common ingredients would be cetearyl alcohol or stearyl alcohol (maybe even better).

Surfactants are emulsifiers as well and this product is packed with them; plus, the thickening agent (cetearyl alcohol) is also a co-emulsifier (if that was needed) so there is really no need to add any extra emulsifier (I have seen some recipes with ewax, well I wouldn’t add it here). 🙂

Now, finally, to the RECIPE (at the end I have added a little comment on the formula):

SLSA 35% 
SCI 10% 
SCS 10% 
Cocamidopropyl Betaine 20% (this is the only liquid surfactant – it is needed to decrease the aggression of ionic surfactants. If you don’t have so many different powder surfactants it is still ok as long as you do have the CAPB)
Butters and oils mix 10% (I have used cocoa butter 7% and argan oil 3% – you can use whatever you like, but keep in mind that you need the shampoo to be really solid so try to use butters and not too many oils)
Behentrimonium Chloride 10% 
Cetearyl Alcohol (I had a 50%-50% one) 3%
Fragrance Oil 1.5% 
Preservative 0.5%

HOW TO:
1) Measure the surfactants (excluding the cationic one for the moment)
Solid Shampoo (13)

2) Melt them – this will take longer than you might think; luckily the water of the liquid betaine will make the process faster.
Solid Shampoo (15)

3) Measure the butters, the cationic surfactants and the thickener (Behentrimonium Chloride and cetearyl alcohol are in the same becher on the right)

4) And add them to the magic cauldron 🙂
I didn’t melt them separately first, but I suggest you to do it! (it will speed up the process)
Solid Shampoo (16)
(Yes, it does look like a mess!) 🙂

5) Once all looks homogeneous, take it out from the hot bath and keep stirring slowly until it is not too hot anymore (check the temperature: around 35°C). At this point add the last ingredients (fragrance oil and preservative… I have added a drop of colorant as well)

6) Put the soapy paste into molds
Solid Shampoo (6)

7) The easiest thing to do is place the mold in the freezer until the solid shampoos are hard enough to be unmolded and let them dry for a couple of days before trying to use them.
Solid Shampoo (14)

🙂

This is a simple recipe without any “extra” ingredients. You could add some hydrolized proteins (1%-2% for example) at cool down, or even D-panthenol (not too much, cause anyway all these ingredients are washed off moments after).

How I have found this shampoo:
It had a very high wetting ability, with an extremely soft lathering made of small bubbles. This was very comfortable.
What my head didn’t like were the waxy and buttery ingredients: even if there were all these surfactants, I still felt like the shampoo wasn’t cleaning enough. Next time I will lower the percentage of butters and oils and see if the result is more balanced 🙂

Solid Shampoo (1)

13 thoughts on “How to Formulate a Solid Shampoo

  1. Vicky says:

    Thanks for your amazing blog, I’ve just found it and I’m going to read through all your posts for sure! I’ve been “playing around” with making solid shampoos as well. I love the way they work and how convenient they are for traveling, etc. Maybe you can help me figure our some of the stuff about formulating them?
    1. I haven’t used preservative before, why is it needed if we don’t add any water to it?
    2. I’ve started using a combination of SCI + SCS for milder effect, is there a way to choose even milder surfactant combination? Because like you said, at such high concentration it might be a little too drying on the scalp and too aggressive.
    3. I have cocoamidopropyl betaine at 35%, sorry for a silly question BUT: for example in this recipe of yours, do I just add my CMDB mixture at 20%? OR do I need to calculate that the active surfactant matter is 20%?
    4. Do you have a post about Behentrimonium Chloride? What does this ingredient do, and especially why do we use in it in this recipe?
    5. In making SOLID cosmetics, how important is it to mix ingredients in separate phases? When I made my first solid shampoos I simply melted everything together (even panthenol) but it seemed to work just fine! So could you let me know what is the difference if I add them separately like in your recipe?
    6. Do you have some suggestions of what other ingredients could be incorporated here to improve the recipe?

    Sorry for flooding you with questions. Hope you have time to look though them. Please don’t stop posting, keep this wonderful blog up! Cheers!

    Like

    • It's all in my hands says:

      The preservative is usually not needed if there is no water BUT if there is high chance that the products gets in touch with water, then you should add it (and a solid shampoo is definitely going to touch water)
      I think ALL solid shampoo formulas are too aggressive unless there are many butters, in which case they don’t wash enough! 🙂
      The CAPB you have is the right one for this formula. No need for more calculations.
      Behentrimonium chloride: I dont have a post about it but I have used it in other posts. It is a good hair conditioner. It is a little wasted here but it helps making the formula milder.
      The panthenol shouldn’t be heated so you should add some ingredients towards the end (while cooling down) cause the high temperature spoils them.
      🙂 Hope this helped!

      Liked by 1 person

  2. bre says:

    Can you use decyl glucoside in place of the cocamidopropyl betaine? or is there anything else to use in place of it? it seems to be irritating to a lot of people.

    Like

    • It's all in my hands says:

      Hello Bre.
      The cocamidopropyl betaine in this formula is exactly to lower the irritable effect of the anionic surfactant. Decyl glucoside wouldn’t really work the same way.
      If you have problems with CAPB you can make a shampoo using glucosides, for example, without any problem… but I wouldn’t simply substitute CAPB with decyl glucoside in this formula.

      Like

  3. bre says:

    Thank you for replying. I am confused though, you said I could substitute with glucosides, but decyl glucoside isn’t a glucoside? What about coco glucoside? Sorry if that is a dumb question I am really new to this!

    Like

    • It's all in my hands says:

      Hello Bre, no problem but I said something else.
      I said that I don’t suggest substituting the CAPB with a glucoside in this formula, but you can make a shampoo based on glucosides (decyl gl. included) creating a different formula 🙂

      Like

  4. alicia says:

    FINALLY, an awesomely informative post on solid shampoo making! Thank you so much I’ve been looking all day. My husband has been nagging me for an all-in-one shampoo bar for camping.. Could I get a comment on this potential formula:

    SLSA 40%
    SCI 25%
    (I don’t have SCS, can I leave it out?)
    Cocamidopropyl Betaine 20%
    Butters and oils mix 7% ( butter 5% and KUKUI oil 2%)
    BTMS 5%
    Cetyl Alcohol (instead of cetearyl?) 5%
    Essential Oil Tea tree & Rosemary 2%
    Preservative 0.5%

    Really appreciate your comments!!

    Like

    • It's all in my hands says:

      Which preservative are you using? I would increase it to the maximum suggested percentage, because the shampoo bar is dipped in water at every use and therefore it is susceptible of being contaminated very easily! 🙂 This said, I think the formula looks fine.
      I have to say thought that after this attempt I only made it once more, because I didn’t like the effect on my hair. But that’s just my preference. For camping it sounds as a good solution (clearly it can be used like a soap as well, so it is an “all in one”).
      Let me know how the experimenting goes (make a small batch first, so you can tweak the formula if needed). Happy Experimenting!

      Like

  5. alicia says:

    Thank you for such a prompt response and that I only just found this thread again after the crazy weeks I’ve had!!.. Nipaguard SCE is the preservative I will use, good advice, will increase..I MUST find time to make a test batch today – shall update (:

    Liked by 1 person

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