Shampoo bars are basically solid shampoo, but the actual cleansing ingredients are far more concentrated due to solid form, so they last longer. We use mild surfactants and add in other hair and scalp beneficial ingredients to create a mouldable putty type texture that can be shaped by hand or pushed into a mould and left for a few days to dry out before using.
You wouldn’t normally use BTMS 50 and Polyquarternium 7 with anionic surfactants as they are opposite charges and would essentially repel each other leaving an unstable formulation with lumps -these are known as complexes. However, in shampoo bars we can get away with this as they aren’t a liquid with lots of water, and water is required to form the complexes. There are of course, some cationic ingredients designed specifically for products like 2-in-1 liquid shampoos where they will happily mix if combined correctly. So, in short, because we have no water in our formulation, the anionic and cationic ingredients can happily co-exist and do their thing on our hair when we use the shampoo.
There is however, a teeny amount of water in the formulation, but this is within the Cocamidopropyl betaine (used to increase foam and make the formulation milder) and since the Polyquarternium 7 is a water soluble ingredient we can incorporate the two before adding in order to combine. I hope that made sense. Formulating involves a lot of ‘balancing’ of charges, solubility, pH tolerance etc, so reading up and gaining an understanding of these things will help a lot with your formulation journey.
To use a shampoo bar, you massage it over your wet hair and scalp, and it will lather and foam just as a normal liquid shampoo would.
So, ASM – Active surfactant matter. The ASM is obviously a lot higher in shampoo bars due to the high amount of powdered surfactants. Usually around the 50% mark is good. We have SCI with an ASM of 85%, SLSa with an ASM of 65% and Cocamidopropyl Betaine with an ASM of 30%
30% usage rate of SCI = 30 x 0.85 = 25.5% ASM
30% usage rate of SLSa = 30 x 65% = 19.5% ASM
10% usage rate of Cocamidopropyl Betaine = 10 x 0.30 = 3%
Total ASM for finished product = 25.5 + 19.5 + 3 = 48% ASM
I’m happy with that, lets give this a try…
Formula and recipe for 500g Batch
30% SLSA (INCI: Sodium lauryl sulfoacetate) – A mild anionic surfactant that cleanses and lathers to remove dirt and oil without stripping the scalp and hair.
30% SCI (INCI: Sodium Cocoyl Isethionate) – A mild anionic surfactant that cleanses and foams.
5% Kaolin Clay (INCI: Kaolin) – adds to the creamy lather of the bar and helps to cleanse the scalp.
3% BTMS 50 (INCI: Behentrimonium Methosulfate (and) Cetyl Alcohol (and) Butylene Glycol) – conditioning Cationic emulsifier, added here purely to add a bit of conditioning to the hair and help to bind the ingredients and make the overall product milder to use. At this low percentage it will not add any hardness to the bar.
2% Mango Butter (INCI: Mangifera Indica Seed Butter) – A very effective scalp conditioner, helping to strengthen hair follicles to prevent breakage and hair loss. It seals in moisture and helps to prevent frizz.
1% Stearic Acid (INCI: Stearic Acid) – A fatty acid that adds extra conditioning properties to the bar. Can be used to harden a little, but mostly for conditioning at this low percentage.
14.9% Honey (INCI: MEL) – An emollient and moisturise that smooths the hair shaft, adds shine and acts as a humectant locking in moisture.
10% Cocamidopropyl Betaine (INCI: Cocamidopropyl Betaine) – Amphoteric surfactant that when paired with SCI and SLSa, helps to make the mixture milder and prevent irritation. It’s moisturising and texture enhancing and helps to boost bubbles.
2% Mango Fragrance Oil (INCI: Parfum) – Our fragrance, you can swap for essential oils if you wish (check IFRA for allowed usage rate)
1% Polyquarternium 7 (INCI: Poly(acrylamide-co-diallyldimethylammonium chloride) – a cationic conditioning agent. It’s water soluble but and premixes well into the cocamidopropyl Betaine in order to incorporate it into this anhydrous formulation.
1% Preservative Eco (INCI: Benzyl Alcohol, Salicylic Acid, Glycerin, Sorbic Acid) – Broad Spectrum preservative. Not technically required since it’s an anhydrous product, but because of the way it will be used and likely water will collect on the surface over time due to storage, we should include one.
0.1% Mica (INCI: CI 77019 + whatever else is in your chosen colour) - for colour – you could add water soluble dye to the cocamidopropyl betaine since it’s water soluble, but you will need a lot less than this, as these dyes are potent!
You have two choices here. You can either hot or cold process this shampoo/Syndet bar (Syndet stands for Synthetic detergent, as it is not a soap recipe).
First put on a respirator. It’s dangerous to breath in these fine surfactants. Ventilate your work area well!
If you choose to hot process it, you can get a smoother finish. To do this, heat the surfactant phase A in a heat proof bowl, and phase B in another heat proof bowl. When both are melted, you can combine, keeping on a gentle heat so they don’t solidify before combining, stirring to combine. Once combined add your Cocamidopropyl betaine and honey and stir to combine.
The tricky part now is combining the cool down phase as the mixture will need to be 40C or below and will be starting to harden.
For this reason, I have chosen to cold process the formula. To do it this way, combine phase A in a bowl. Melt down phase B. Once melted, add to phase A along and stir. It should be instantly cool enough to add your cool down phase C, so add your Polyquarternium 7 to the Cocamidopropyl Betaine and gently stir then add this mixture along with your other cool down ingredients. Stir with a metal or silicone spoon or spatula until combined. If you want you can get in there with your gloved hands and knead it into a dough like texture.
Now, take a small blob and mix it into some water to later and test the pH. You may need to adjust. Mine came out at a 7, which for shampoo I am fine with, but if you would like to balance it lower, then you might like to add a few drops of citric acid solution to your mixture when you add your wet ingredients. This will be trial and error batch to batch as you can’t adjust sufficiently when its in its dough form.
Once you are happy, you can mould it into shapes or press into moulds to shape. Then leave to harden for a few days before using so that the water content in the Cocamidopropyl Betaine and any water soluble/water containing ingredients can evaporate off.
I made this to make use of ingredients that I had in stock, so you can absolutely make substitutes, though this will change the final product.
If you want the bar to be more cleansing, then SCS is a very good surfactant for shampoo bars. Make sure that you check usage rates, for example, we are combining SCI and SLSa because SCI cannot be used past 50% in this kind of product, therefore we needed to ‘top up’ with something else. I decided to strike a balance between the two, but you can portion it how you like. The SLSA I used was a bit lumpy and I forgot to grind first, so I ended up with a few lumps. You can avoid this by grinding first or doing the hot process method.
You can replace the honey with an oil if you wish.
You can add more actives in the cool down phase. Just remember that this is a rinse off product, so don’t waste expensive ingredients. Save those for leave in conditioners etc.
My advice with shampoo bars is to use just enough conditioning ingredients to keep the hair tangle free and feeling soft after use, as a shampoo bar just with cleansers can be a bit too cleansing and draggy and drying.
Disclaimer: These formulas and recipes are experiments created for the purpose of sharing on Patreon and YouTube. Revega does not make any claims as to their qualifications or the efficacy of the formulations which are listed here for entertainment purposes and accepts no responsibility for how you use these. We are self-taught and offer these videos from our years of knowledge and experience in making our own cosmetic products. Remember, that if you intend to use one of these formulations for your own product range, do your own research, experiments, adjustments and tests before using, gifting or selling.