Is SLS Really the Enemy? A Deep Dive Into Surfactants in Skincare
How Do Surfactants Work?
Surfactants work by bridging the gap between oil and water. When you apply a cleanser containing surfactants to your skin, the hydrophobic tail of the molecule binds to oil, dirt, and makeup, while the hydrophilic head binds to water. When you rinse, the entire molecule, along with everything it's attached to, is washed away.
This action is what gives cleansers their foaming, cleansing power and their ability to remove buildup effectively.
Types of Surfactants in Skincare
Surfactants fall into four main categories, each with different cleansing strengths and levels of irritation potential:
Anionic Surfactants
Strongest cleansing agents
Common examples: Sodium Lauryl Sulfate (SLS), Sodium Laureth Sulfate (SLES)
Known for: High foaming ability, but often criticized for being harsh and potentially irritating to sensitive skin types
2. Cationic Surfactants
More commonly used in conditioners than in facial cleansers
Can have antimicrobial properties but may also cause irritation in higher concentrations
3. Nonionic Surfactants
Much milder, often used in gentle or hydrating cleansers
Examples: Decyl glucoside, Coco-glucoside, Polysorbates
Known for: Being effective yet non-stripping, great for sensitive or dry skin
4. Amphoteric (Zwitterionic) Surfactants
Balanced, adaptable based on pH
Example: Cocamidopropyl betaine
Often used in baby products and sensitive skin formulations
So... Is SLS Really That Bad?
Sodium Lauryl Sulfate gets a bad reputation for a few reasons:
High irritation potential: On its own, it can be too strong for the skin barrier, especially for dry or sensitive skin.
Dehydrating: It may strip the skin’s natural oils, leading to tightness or redness.
Outdated formulations: Many older products relied heavily on SLS without balancing it with gentler surfactants or hydrating ingredients.
But here’s the nuance: formulation matters more than any single ingredient. A well-formulated product may contain SLS in combination with soothing, moisturizing ingredients or paired with milder surfactants that reduce its irritation potential.
Not everyone reacts poorly to SLS. For example, oilier skin types or those living in very humid environments may tolerate it just fine.
What Should You Look for in a Cleanser?
When choosing a cleanser, instead of fearing one ingredient, ask:
Does your skin feel tight or dry after using it?
Does your skin feel clean but not squeaky?
Is the cleanser helping your skin, or making it feel worse?
Also, look for cleansers labeled as:
pH-balanced
Sulfate-free (if you're on the sensitive side)
Barrier-supporting (often containing ceramides, glycerin, or fatty acids)
Final Thoughts
SLS isn’t inherently evil, but it’s not always necessary, especially with today’s advanced formulations. Many modern cleansers use gentler surfactants that are just as effective without being overly stripping. Still, knowing your skin type, environment, and product formulation will help you make the best choice.
The takeaway? SLS may be too much for some, but it’s not universally bad. As with most things in skincare, context is key.
My Favorite Cleanser Pick
If you're looking for a cleanser that strikes the perfect balance between effective cleansing and skin barrier support, I highly recommend the Colorescience Barrier Pro Cleanser. It’s formulated to gently remove makeup, sunscreen, and daily buildup without disrupting the skin’s natural moisture barrier. This cleanser is appropriate for all skin types, even sensitive, and is a great example of a formula that uses surfactants thoughtfully to cleanse without stripping.
