Saturday, August 15, 2009

Mineral make-up ingredients: Magnesium stearate

Ah, finally back to molecules for my illustrations!

Magnesium stearate (or octadecanoic acid) is a metallic soap that insoluble in water. It's all about the adhesion with this ingredient. Because it repels water, it will keep your products on your skin all day long, and because it'll absorb oils, it's a a good choice for oily skinned women.

If you want to press your powders, then magnesium stearate is your ingredient! You can use it in foundations, blushes, or eye shadows to create pressed powders you can store in a compact.

Because it's all about the adhesion with magnesium stearate, it can reduce the slip, glide, and skin feel of your mineral make-up product. So make sure you keep it at a low level - 3 to 10% - and compensate with lots of slippery goodies like silk powder or sericite mica or Micronaspheres.

It can be derived from animals (generally cows) or vegetables, so if you are concerned about this, ask your supplier.

SUMMARY OF MAGNESIUM STEARATE
Usage rate: 3 to 10%. Higher levels can lead to blotchiness on the skin.

Whiteness or opacity: To make a colour lighter, to cover up imperfections.
Translucency: The base itself is almost invisible once applied.
Neither of these are applicable as it doesn't change the colour or opacity.

Skin protection
Can offer a little moisturizing as it is a stearate.

Slip: The product feels nice going on and staying on.
Magnesium stearate will increase the drag, so keep it at lower levels.

Adhesion: The product remains on your skin.
Superior adhesion. This the reason to include magnesium stearate in your products.

Absorbency: Your colour will remain true throughout the day and not morph into something due to environmental stresses or skin oils.
It loves oils, so it's an excellent absorber.

Light scattering properties: To give your skin a dewy glow.
Not applicable for magnesium stearate.

Let's make a pressed powder out of one of my favourite eye shadows - SUB-LIME! (although you could use any eye shadow of your choice). You'll want to add 3% to your recipe - which works out to 3 small 0.15 scoops for every tablespoon of eye shadow. (Or blush or foundation or whatever you're pressing). You may need to increase it to 5% if you find you can't press it properly.

SUB-LIME (lime green - bright with sparkles) - 1 eye shadow container
4 scoops basic eye shadow base (click here for basic base and alternate base)
6 scoops apple green pop mica
12 scoops lemon drop pop mica
2 scoop strawberry pop mica
1 scoop magnesium stearate

Put all ingredients in a bag and squish together until you're happy with the colour. If you want a less green colour - and why would you? - you can reduce the apple green to 3 to 4 scoops.

To press your eye shadow, pour your ingredients carefully into a hinged compact or sifter jar and press down with a quarter or something similarly sized (very very clean), depending upon the shape of your container. Hold for a minute or so, then release. You've got a pressed shadow!

As a note, Tanna from Suds & Scents has some instructions on how to use dimethicone or oils as binders to make a pressed eye shadow.

Join me tomorrow for the fun and excitement of boron nitride!

7 comments:

Leanne said...

Hi, I would prefer not to use Magnesium Stearate - could you recommend what I could use as an alternative?
Thanks for your time.

Elaine Lombardo said...

Hi - I want to make loose eye shadows using the micas I have. I have magnesium stearate already but I want to add something for slippage. I have kaolin clay, cornstarch, tapioca starch. Can you recommend a good combination of any of these ingredients? Do any of them work for slippage so I can add them along with the magnesium stearate? Thanks so much for your advice!! Elaine

Susan Barclay-Nichols said...

Hi Elaine. I have many recipes for bases in the mineral make-up section of the blog, so I encourage you to check them out. I go through what each ingredient is and does for a product, and show examples along the way.

Anonymous said...

Hi Leanne. What is wrong with Magnesium Stearate... I read it is safe but then I read that it is made of cottonseed oil or palm oil which can have pesticides. Is it safe or not? :(

Susan Barclay-Nichols said...

Hi Anonymous. Please revise your comment with your name or I'll have to delete it. Wgat I will say is this...would I suggest an ingredient for my lovely readers to use if it wasn't safe? Would I make things with it and give it to my friends and family if I thought there would be a concern? I consider this a safe ingredient.

Wish said...

I have an allergy to magnesium stearate. Can you suggest an alternative?

Susan Barclay-Nichols said...

Hi Wish! Check out the mineral make up section of the blog - the link is in the right hand side column - and check out the other fillers there to see what would be a good substitute. As this ingredient has many properties, you'll have to figure out which ones are important to your product and what works in its place.