Shampoo Formulating (for a first-timer)

Hey folks.

This is my first time. Thanks a bunch for the thoughtful discussions here! I was hoping I could get some guidance and feedback on a shampoo formula.

First let me be clear and say I’m not a chemist. Far from it actually. My degree field is in finance and I’ve worked in corporate finance my whole career. A few years back I discovered soap making as a hobby and absolutely buried myself in it. I love researching and reading. I became an obsessive soap nerd. Fast forward and I now run a little hobbyist business selling artisan shaving soap. It’s not serious (and I don't want it to be), but it keeps my nights and weekends busy.

Lately I’ve been super curious about the formulation of shampoo. I’m hoping to get some direction from people who know a lot more than I do. Keep in mind, I’m just starting this journey, so please tear this apart if it’s necessary. This is a long-term undertaking of experimentation.

Here’s kind of where my research has led me:

Water: ~70%

Sodium Laurel Sarcosinate: ~10%

Coco Betaine: ~10%

Sodium Cocoyl Isethionate: ~3%

Glyceryl Cocoate: ~2%

PEG-8 Dimethicone: ~3%

Hydroxypropyl Methylcellulose: ~1%

DMDM Hydantoin: ~0.3% (I also plan to experiment with Germaben-II)

Trisodium Ethylenediamene Disuccinate: ~0.2%

Fragrance

 

Do you see any red flags here? Any ingredients that aren’t going to play well with each other or an obvious gap?

I’m going to experiment, but what is the best step-by-step to create the product with these ingredients?

My current plan of attack was to combine the water and liquid surfactants and heat them up in short bursts in the microwave, primarily because I need to dissolve the sodium cocoyl isethionate somehow. I use SCI in some of my more complex soaps (it’s a great ingredient), but it’s a pain in the you-know-what to work with, specifically in hot process soap. It doesn’t really melt, which is a huge pain in high-stearic HP soaps, and its pH is slightly acidic, which, again, is a problem in self-preserving products like soaps. Not only that, but it can neutralize the lye and prevent proper saponification if not used correctly. Anyway, what’s the best way to incorporate SCI in a shampoo? I’ve found virtually no literature on this.

I was then going to add the silicone (careful to cool down the mixture beforehand) followed by the preservative, chelator, and fragrance (I read PEG-8 Dimethicone has emulsifying properties and I’m wondering if it alone will be enough to emulsify fragrance oils? Do I need a separate emulsifier?).

Lastly, incorporate the cellulose thickener.

To be clear, I have no idea if this is anywhere close to the right process. I generally learn by failing enough times until things work out (:

Thanks so much in advance, all.

Comments

  • Hi @glachney

    I thought I am the only full-time financial advisor who obsessively formulates on weekends on this forum. So, not a chemist either and not particularly familiar with Sodium Laurel Sarcosinate, but I can comment on some other points.

    PEG-8 Dimethicone is great and you should definitely keep it. It does have some emulsifying properties (as many other PEGs) but not enough to solubilize fragrance. The best solubilizer for this purpose is PEG-40 Hydrogenated Castor Oil. I like it much better than Polysorbates. Alternatively, use Polysorbate 80.

    Tetrasodium EDTA is better when you want to get a clear product. Also, there is no need to add it in the end as far as I know.

    The last one, those sulphates elevate pH. Make sure you add citric acid in the end to bring the pH down to 5-6.

  • @ngarayeva001 you’re a rockstar, thanks! Kindred spirits we are. It’s really fun finding hobbies so far out of your area of exposure that the only option is to start researching like a mad man. 

    I’ll definitely check out PEG-40 Hydrogenated Castor Oil and also be sure to keep an eye on pH. Thank you for that feedback. What’s the practical reason for shampoo needing to be on the acidic side? Shampoo bars for example are up near 9-10+, right? 

    Where did you learn some of the foundational stuff? Like understanding Chemistry 101. I somehow made it through my whole schooling career without a single Chem course, so I often find myself researching something and easily getting tripped up in the nomenclature and explanations. 
  • @glachney, ideally all skin and hair product should have pH below 7, since our skin has a pH between 4.5-5.5 and hair even less (btw hair conditioners should be below 5 to work). My understanding is that all products with pH >9 are in that range not because it's good for skin/hair but because there is no way to reduce pH of that particular product. 

    I had no understanding of chemistry when I started formulating. I was changing firms and had a couple of months lag between jobs. And I thought that taking a $350 moisturizer, reading it's endless LOI and attempting to recreate it was a good idea :smiley:  And then I ended up with 28 ingredients from makingcosmetics and no idea how to mix them.
    Jokes aside, it's trial and error. I analyze LOIs of commercial products a lot. Beautypedia.com is a place where you can search for products by type and brand and lookup LOIs. I recently found swiftcraftymonkey blog (paid subscription). There is a lot of good information there. And this forum is absolutely amazing. 
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