What Is Stearic Acid? Benefits and Uses in Skincare

Stearic what? Don’t worry, you’re not alone. This quiet achiever has long been a key ingredient in daily skincare routines, without us even knowing! But that’s about to change. It’s time to shine a spotlight on this hard-working acid, and give it the love it deserves. Scroll on. 

Okay, what is stearic acid?

Firstly, it’s not really an acid. (Way to kick off with a mic drop, we know.) At least, it’s not an acid in the way we understand acids in skincare. We generally think of acids as active ingredients, designed to exfoliate and hydrate. Stearic acid is what’s known as a long chain fatty acid. Long chain, to translate, means more carbon atoms, which means more likely to be absorbed by skin lipids (and less likely to irritate – yay!). As a naturally occurring fatty acid, stearic acid is already working hard in the human body (cell membranes, we’re looking at you) and in plant-based fats, like shea butter and cocoa butter. 

Yeah, but what are the benefits? 

Most acids are used in skincare products for either formulation purposes or to deliver targeted benefits to your skin. Stearic acid? It does both. (Told you it was a hard-worker.) It functions in a few different ways.

Emollient
Emollients are a powerhouse. They work to smooth and soften the skin’s surface, by trapping moisture in the skin and filling in the gaps between skin cells. Not in a pore-clogging way, don’t worry. Instead, emollients keep hydration locked in and skin irritants out. Music to our ears. 

Surfactant
Surfactants are a key player in cleansers, thanks to their ability to switch up the surface tension on skin, making it easier for water to penetrate (and wash away) oil and dirt. Even better? Surfactants work to clean your skin without disrupting the natural oils on your skin, meaning you’re less likely to get that post-cleanse squeaky-clean tightness (no thanks). 

Emulsifier
Emulsifiers work their magic by helping combine ingredients that don’t usually play well together, like oil and water. They help products work more effectively, and prevent ingredients from separating, making formulations more stable and long-lasting. Emulsifiers also get bonus points for creating that velvety-smooth texture we love smearing all over our skin. Mmm…

What a combo, right? Not only does stearic acid make the products it’s found in more effective, but it also works to keep your skin hydrated and protect your skin barrier (aka. the thing always in need of a little more love). Hello, triple-threat. 

But, is stearic acid safe?

Stearic acid has long been used in skincare, bodycare and soap, and is generally safe to use! When properly formulated, stearic acid has the ability to moisturise, cleanse and protect your skin with minimal risk of irritation. For expecting parents, doctors do recommend limiting its use during pregnancy, so it’s worth having a chat with your GP if you’re unsure. 

So, there it is. The low-down on stearic acid, the skincare sidekick doing good things for your skin (and your skincare). Hydrating, smoothing, cleansing and keeping your fave formulations in check. So, next time you’re rummaging through your routine, keep an eye out for this hidden hero.

Feeling the love for hydration and cleansing? Check out some of our faves. 

🍓Berry Exfoliating Body Wash
🍓Very Berry Body Whip Moisturiser 

Happy Sundae x

Written By: Lizzie Waley (Sundae Co-Founder & Body Care Enthusiast) | LinkedIn

Fact Checked: Charnnie Frimpong (Sundae Content Marketing Manager) | Linkedin