Soap: A Slippery Slope

Soap has a classic image—basic, pure, just fats or oils saponified with an alkali like lye. But in

today’s beauty and personal care market, the waters are murky. When you wander into the

world of “cleansers,” things get complicated with surfactants, detergents, and products like

micellar water. While these products serve to cleanse, they often don’t meet the strict regulatory

definition of “soap” and are therefore classified as cosmetics.

What Are Surfactants and Detergents?

Surfactants are the powerhouse of modern cleansers, found in everything from shampoos to

facial washes. They’re designed to reduce the surface tension between water and oils, allowing

products to lift away grime without the saponification process. Detergents, like the sulfates

found in many shampoos, are a type of synthetic surfactant that can effectively clean but are

often milder and more flexible than true soap.

The FDA considers a product to be “soap” if it’s made by saponifying fats with an alkali, without

added synthetic detergents. If you start adding surfactants or detergents to boost lather,

gentleness, or skin benefits, you’ve crossed over from soap into cosmetic territory.

Cleansers Like Micellar Water: Not Soap, But Also Not Drugs

Micellar water is a great example of how modern cleansing products work outside traditional

soap definitions. Formulated with “micelles”—tiny molecules that trap impurities—micellar water

removes dirt, oil, and makeup without foaming or rinsing. But because it’s not made through

saponification and doesn’t contain traditional soap ingredients, micellar water is classified as a

cosmetic.

While micellar water isn’t considered soap, it’s also not a drug, as it doesn’t promise to alter or

treat any skin conditions. Instead, it serves a simple cosmetic function: cleansing and

beautifying without any therapeutic claims.

Navigating Regulatory Classifications

Here’s the takeaway: the line between soap and cosmetic is stricter than it might seem. Plain,

saponified soap stays within the Consumer Product Safety Commission’s jurisdiction as a

“commodity,” but once you step into surfactants, detergents, or products like micellar water,

you’re in the cosmetic world regulated by the FDA.

The rule of thumb is that if you’re making claims beyond cleaning—like “moisturizing” or “anti-

aging”—your product is likely a cosmetic, not just soap. And with that, regulatory compliance

becomes more complex. So, while soap may be simple, the regulations behind it are anything

but.