Thursday, May 26, 2016

One ingredient, five products: Stearic acid - a thicker foot cream

Stearic acid is a natural inclusion in a cream. In fact, you can thicken any basic lotion into a cream by adding some stearic acid. We took a look at a hand lotion yesterday. Let's take a look at a cream today.

Actually, let's back up a second. What's the difference between a cream and a lotion? Or an emulsified body butter and moisturizer and creme and... There are no definitions for anything other than a lotion, which is a product that uses an emulsifier to bring together oil and water. You can call a thick, rich cream a facial moisturizer and a thin, sprayable lotion a body butter. There are no definitions for it. We have an idea of what it means when someone says a product is a cream versus a moisturizer, but that isn't necessarily so.

In this case, what I mean by a cream is a product that is quite thick and should be pumped out of a bottle or scooped out of a jar. For this product, I definitely recommend a nice, sturdy pump, not a teeny tiny treatment pump you'd use for a thinner lotion, like a moisturizer.

I'm basing this cream off the recipe you can find as a newbie recipe in this post, but we'll make some modifications. I want to use this as a foot cream, so there are some things I can change to ensure it'll be a nice lotion!

When I'm making a foot cream, I'm thinking greasy and thick. I want something that goes on well and moisturizes even better. I want something that will help my completely trashed heels feel softer and hydrate dry skin. And I don't want to use fancy and expensive oils here. This isn't some frou-frou moisturizer with live plankton and seaweed extract that comes in a 30 ml shiny glass bottle. Nope, this is a thick, buttery cream you can make by the bucketload intended to be slathered on your feet and covered up with your very thickest socks!

My first thought is to include two humectants into the mix to draw water from the atmosphere to my skin. I'll include glycerin at 3% and sodium lactate at 2% to get the most hydration possible. You could use something like hyaluronic acid at 1%, but why would you use something expensive and decadent like that on your feet? You probably don't mind the slight stickiness of glycerin on your feet all that much, and it's a great humectant.

As a note, I once made a foot lotion that was 25% glycerin! I know, right? Sounds insane, but it was totally awesome. I can't share the recipe here as it wasn't my original creation, but I can suggest that you could substitute 25% glycerin for 25% water in this recipe and see what you think. It will make your feet feel quite cold, so be aware of that, and you may even have pruny toes in the morning as it's quite hydrating! 

When I make foot creams, I generally include an oil that contains a lot of Vitamin E, which softens skin, and linoleic acid, which will help speed up skin's barrier repair mechanisms. My first choice is generally soy bean oil because it's got a lot of both, and has a one year shelf life. It's a greasy feeling oil, but do you care that much about greasiness when you've got a lovely pair of socks on? Rice bran oil is another lovely choice, and has a shelf life of about a year. It's less greasy feeling than soy bean oil. I'm actually going with rice bran oil as I'm out of soy bean oil, but either would be lovely here.

When it comes to butters, I can use just about anything here. Cocoa butter is generally my first choice as I always have it in my workshop, plus it's a great barrier protectant, but any butter will do. Shea butter will feel a bit greasier, mango butter less greasy.

We're using stearic acid here to make a thick, tenacious lotion that will go on and stay on for quite some time. You could substitute cetyl alcohol or another fatty alcohol if you wish, but doing that will miss the point of this series!

One thing I love to add to foot lotions is menthol. I use menthol crystals at 3% in the heated water phase, but you could use peppermint essential oil at 1% in the cool down phase. Menthol can make your feet feel cooler and increases circulation, both of which are awesome for foot products.

Sometimes I add up to 1% camphor essential oil and 1% eucalyptus essential oil into the cool down phase to make the product smell like Vick's, but I didn't have any of either, so I left it out. It is a really neat smell and clears your sinuses up something fierce!

54% distilled water
3% glycerin or other humectant of choice
2% sodium lactate
3% menthol crystals

15% rice bran oil
10% cocoa butter
7% Polawax or BTMS-50 (8% e-wax NF)
3% stearic acid

0.5 to 1% preservative
1% fragrance or essential oil blend

Please use the basic lotion making instructions for this product. If you want more detailed instructions, click here for the cream making tutorial. As with all my lotion recipes, you can substitute any oil for any oil, any butter for any butter, and any oil with any butter and vice versa. You can substitute 10% aloe vera for 10% distilled water, add a nice water soluble extract, or change the essential oils. It's really up to you!

What did I think of this lotion? I really like it. I do think sometimes I want to leave out the menthol because it's annoying to have to get up and wash my hands of it before going to bed, but I do like the cooling effect it has. It's a very thick cream that still feels like it's on my feet in the morning. I think I'll up the glycerin to 5% next time (removing 2% from the distilled water amount) as I do like the feeling of hydration it offers.

Other posts in this series:
One ingredient, five products: Stearic acid
One ingredient, five products: Stearic acid - a hand lotion

Related posts:
Using peppermint in foot care products
Foot lotion becomes foot cream
Body butter becomes foot cream
Creating a foot cream, part one (click "newer post" to get to the other parts)

Join me tomorrow as we take a look at making a solid scrub bar with stearic acid!


Anita said...

Thank you for this.

Quick question since I've never used menthol crystals before. Is the potency of their fragrance compromised by being heated with the water phase? I notice that you include fragrance as well, so are the crystals just being used for the "cooling" effect rather than scent?

~Mrs. Spaceship

La Prairie Lady said...

Great post I want to make this cream, I already make a cream wit Pepermint with olive oil not greasy. My husband use Icy Hot roll-on and read their ingredients, so easy to make at home

Active Ingredients: Menthol (16% (Topical Analgesics))

Inactive Ingredients: Acrylates/C10 30 Alkyl Acrylate Crosspolymer, Capsaicin, Glycerin, Isopropyl Myristate, Propylene Glycol, SD Alcohol 40 (30%), Triethanolamine, Water.

we can forget capsaicin

Sabrina K. said...

OMG! I need to try this! I just wrote down something very similar and was wondering about the percentage of menthol crystal I should use. Thanks for the answer! I was also planning to add a little wintergreen EO to numb the pain when present (lots of walking here).
I have everything and I am off today... Guess what my afternoon will look like?
Yay! Can't wait!

Susan Barclay-Nichols said...

Hi Mrs. Spaceship. Dear God, no. They are very very strong. If you are worried about it, put them into the heated water phase just before removing it from the heat and mixing. As I mention in the post, I often add camphor and eucalyptus to the mix as well, so that would be the fragrance/essential oil. Believe it or not, you can smell those things just a bit over the menthol!

Hi La Prairie Lady! I wouldn't use more than 3% menthol in a product as it can cause extreme tingles. This is is the recommended usage rate. And you could just make quick gel with something that can handle alcohol and oils, and you have the Icy Hot! Sounds cool! (Ha! Get it>)

Hi Sabrina! I don't know much about essential oils, but isn't wintergreen considered one of those oils to use with great care? I'm sure I read something about that.

Sabrina K. said...

Yes Susan, I would never make a product for someone else containing wintergreen EO because it contains methyl salicylate and can cause allergic reactions for those who are allergic to aspirin. Thankfully, I am not allergic, and this EO is a fabulous anti-inflammatory that works wonders (external use only) on my feet and knees. It litteraly puts the pain to sleep. I make myself an oil with a St.John's wort infused oil base and 5 EOs and it has been working better than most products on the market.
This said, those little witchy things I like ----> for myself only. I don't even try it on my family. I am very aware of the risks, thank you for your concern :D

Alana said...

If I want to make a foot butter (emulsion) with both menthol and peppermint EO, what percentages would you suggest to use for both? Also, would it smell very strong/medicinal? Have you experimented with this before? Thank you!

Susan Barclay-Nichols said...

Hi Alana. There's no point in using both. The menthol is very strong at even small amounts, and it does the same as peppermint oil. Choose one or the other - using both is a waste.

Alana said...

Hi Susan,

I may be wrong, but aren't menthol crystals oil soluble not water soluble? You put the menthol crystals in the water phase in the post. Also, should I use 3% stearic if I plan to use only 25% shea butter (no oils) for my oil phase? Thank you!

Alana said...

As a followup to my previous comment about 25% shea butter, I am using LotionPro 165, which makes thinner and less stable emulsions so perhaps the stearic acid is necessary?

Susan Barclay-Nichols said...

Hi Alana! You can leave out the stearic acid if you're using that much shea butter. If you're altering the emulsifier, you're altering the consistency. The only way to know what the effect might be for your particular modification of the recipe is to try it and see if you like it.

I put the menthol into the oil phase to stop it from smelling up the room when it starts to melt a bit.

Vintage Blue said...

Hi Susan,

Do you think that adding zinc oxide to this foot cream would help with cracked heels?