Let's take a look at making a lovely shampoo bar for normal to dry hair with stearic acid as both the hardener and the emollient. (I'm basing it on this recipe, but it's not the same!) If you'd like to follow along with a visual tutorial, please click here.
How will a shampoo bar for dry hair differ from one for oily hair? We can't reduce the surfactants as we normally would for dry hair, but we can change the types of surfactants we're using and increase the oils and butters.
Dry hair likes gentle cleansing, so we want to use really gentle cleansers in this recipe. We can use a baby blend type surfactant, decyl glucoside, or SMC or SMO taurate as our liquid surfactants. We can also use more cocamidopropyl betaine to increase mildness. We'll use 15% baby blend, decyl glucoside, or SMC or SMO taurate and 10% cocamidopropyl betaine.
Why are we using liquid surfactants in a solid shampoo bar? Because the powdered surfactants need something to help stick them together!
We want to increase the moisturizing, so let's include more oils and/or butters - you can try something like sal, cocoa, or another hard butter. We know coconut oil is great for hair, but it will soften the bar, so start at 5% and work your way up to 10% coconut oil in this recipe. (I'm suggesting 5% hard butter, 5% coconut oil to start off. If you don't mind it being a bit softer, then 10% coconut oil might work for you.)
We're also increasing the moisturizing by using SCI with stearic acid, which will also serve to make the bar harder. So we're decreasing the SLSa because we'll already have a harder bar and because some dry hair types aren't fans of SLSa. (Consider using another powdered surfactant here - although, to be honest, it doesn't look like any of them will play really well with dry hair!)
If you don't have SCI with extra stearic acid - you can tell because it'll be a prill or little round thing versus a noodle - then you can add more stearic acid to the mix. I'm choosing to use 3% stearic acid with this SCI noodle, but you could use more if you want it even stiffer. There's no value to having the stiffest bar ever as it can break. We want it to have a bit of plasticity to it.
Related posts:
A quick note on SCS: You can get sodium coco-sulfate as a pellet that might work here. This is sodium lauryl sulfate or SLS. Nothing wrong with it in my opinion, but it isn't a gentle surfactant like the ones I suggest in this post.
One of the things we generally like for dry hair are humectants, but adding humectants to this will draw water out of the atmosphere to the bar, making for a really wet bar. This is why we need to use a lovely conditioner filled with humectants after using a shampoo bar. Think of the shampoo bar for dry hair as a great way to wash and moisturize our hair with a little conditioning, but the conditioner bar as being the main moisturizer and conditioner!
CONDITIONING SHAMPOO BAR SUITABLE FOR DRY HAIR
HEATED PHASE
35% SCI (with stearic acid)
22% SLSa or other powdered surfactant
10% SMC or SMO taurate or other gentle surfactant
15% cocamidopropyl betaine
3% stearic acid
3% Incroquat BTMS-50, Incroquat BTMS-25 or Rita 225 or Incroquat CR
5% hard butter of choice
2% hydrolyzed protein
COOL DOWN PHASE
2% panthenol
1% dimethicone
2% essential oil blend
0.5% to 1% preservative
To make this a clarifying shampoo bar, remove the 3% Incroquat BTMS-50 and 1% dimethicone and replace those with 4% emulsifying wax of some kind. Yes, I know I'd normally suggest against including non-ionic emulsifiers in a hair care product in favour of BTMS, but we need something to emulsify the oils so they'll stay on your hair.
Related links:
Other posts in this series:
One ingredient, five products: Stearic acid
One ingredient, five products: Stearic acid - a hand lotion
One ingredient, five products: Stearic acid - foot cream
One ingredient, five products: Stearic acid - body scrub bars
One ingredient, five products: Stearic acid - foot scrub bars
One ingredient, five products: Stearic acid - a hand lotion
One ingredient, five products: Stearic acid - foot cream
One ingredient, five products: Stearic acid - body scrub bars
One ingredient, five products: Stearic acid - foot scrub bars
Join me tomorrow to wrap up what we've learned about stearic acid!