This week's ingredient comes from Isaac in Vancouver, British Columbia.
He wants to know, "What the heck is stearic acid doing in a soap?"
Meet stearic acid.
At room temperature, it's a solid, flaky white substance that looks a lot like laundry detergent
but without the fresh country scent.
It's no wonder.
As a member of the fatty acids family, it's a close cousin to vinegar with its distinctly
sour smell.
Pew.
Stearic acid is found naturally in plant oils and, moo, animal fats.
All right vegans and vegetarians, listen up.
Cosmetic companies don't have to tell you if they use stearic acid from animals on the
label, so contact the company when it doubt.
This is stearic acid on the molecular level.
Horizontally, it's reminiscent of something you may have learned about in high school
health class.
Hold it right side up, and it sort of looks like an electrified lollipop.
Like all members of the fatty acid family, it has a water loving head and a long, oil
loving tail.
What makes stearic acid unique?
The secret lies in the number of carbons found in its tail.
Stearic acid has 18 carbons.
It's the shape and structure that gives this ingredient some really cool capabilities.
Where can we see stearic acid work its magic?
Let's let the smell of camphor, menthol, and eucalyptus take us back to the 1990s.
Doodley doo, doodley doo, doodley doo, doodley doo, doodley doo.
It's the era of frosted pink lips, poof bangs, and, of course, Noxzema.
Instead of obsessing over "Beverly Hills 90210", teenage Ms. B is reading the labels on her
products.
Do you know what the main ingredients are in Noxzema?
Water and stearic acid.
Sweet.
Check it out.
Stick your finger in Noxzema and hear a little crunch.
You are breaking the surface of crystallized stearic acid.
The cream on your finger has a shiny, pearlized look.
This is stearic acid as an opacifier.
Noxzema is not a clear liquid.
It's a thick cream with flecks of crystals.
Did anyone say rhinestones?
Stearic acid is a weak emulsifier.
This is why the cream separates when stirred.
This provides me hours of entertainment when I'm bored.
Lastly, the biggest feature totally can't be seen.
At least not without a microscope.
Stearic acid's water loving head and oil loving tail deliver a beauty aid that is both a moisturizer
and a cleanser.
Meanwhile, back in the 21st century.
Boy, teenage me was a handful.
As beauty moves into the future, stearic acid still finds a place.
For example, we've all heard of Dove Beauty Bar's tagline.
"Contains a quarter moisturizing cream."
Can you guess what the moisturizing cream is?
Yep.
That's right.
It's stearic acid.
Moisturizers work by leaving a thin layer of oil on the skin, trapping water inside.
Without stearic acid to thicken the mixture, Dove's Beauty Bar would be a pile of liquid
goop.
Thankfully for stearic acid's 18 carbon tail, we have an upside, a firm beauty bar, with
a downside of less lather.
Stearic acid is everywhere.
It's in deodorants, toothpaste, sunscreens, lotions, mascaras, and foundations.
Want to talk more about this ingredient?
Then post your thoughts in the comment section below.
Want to hear about another ingredient?
Then give me something to work.
Write me at askme@msbeautyphile.com.
The next ingredient I review could be the one that you requested.