Everything There Is to Know About Sodium Lauryl Sulfate

What dermatologists have to say about the controversial ingredient.


Liz deSousa for BYRDIE

On the list of controversial beauty ingredients, sodium lauryl sulfate sits right near the top, but does it deserve its bad reputation? Sure, you try to avoid it in your hair care products to protect it from stripping your color, but how sodium lauryl sulfate functions in your skincare and the effect it could have on your face and body might not be as clear. To help settle the confusion, we reached out to NYC-based dermatologists Rachel Nazarian, MD, of Schweiger Dermatology Group and Debra Jaliman, MD, along with chemists Victoria Fu and Gloria Lu of Chemist Confessions. Keep scrolling to learn everything you need to know about sodium lauryl sulfate and find out whether you should be avoiding the ingredient in your skincare products.

Sodium Lauryl Sulfate

Type of ingredient: Foaming agent.

Main benefits: Creates a lather, Encourages a deep clean, and Emulsifies.

Who should use it: Those who don't have an allergy or sensitivity to it.

How often can you use it: Can be used every day if you only apply it to areas that harbor bacteria and limit the amount of time on your skin.

Works well with: Moisturizers to counteract the dryness from sodium lauryl sulfate.

Don't use with: Physical and chemical exfoliants, as doing so may further irritate the skin.

What is Sodium Lauryl Sulfate?

According to Dr. Jaliman, sodium lauryl sulfate (aka SLS) is a surfactant that has many different functions, but it acts as a cleansing agent in skincare. It's a type of sulfate and is derived from coconut oil, palm kernel oil, or petroleum oil. Jaliman describes the form as a crystal-like powder, which can be found most commonly in soaps, cleansers, body washes, makeup removers, toothpaste, and shampoos. As a foaming agent, sodium lauryl sulfate can help a product cleanse better or more thoroughly by sudsing up and creating a foamy lather.

Benefits of Sodium Lauryl Sulfate for Skin

A relatively inexpensive ingredient, sodium lauryl sulfate is included in a wide variety of products with a wide range of uses. In skincare, it's predominantly used as a detergent to remove oils.

  • Lathers up: The foamy lather is not only used for its sensory properties (some people simply like the feel of a rich lather), but Nazarian says the suds also contribute to cleaning the area by attracting the oils.
  • Cleans efficiently: Nazarian says by stripping the oils, sodium lauryl sulfate is responsible for giving you that squeaky clean feeling. Thanks to the foamy lather, a little bit of the product goes a long way and in a sense, makes your products a little bit more efficient. "You don’t need much and you feel like you’re getting a bigger clean," she says.
  • Removes makeup: If you wear a lot of oil-based or long-wear makeup, Nazarian says you might find that a sudsy cleanser allows you to break it down and remove it more effectively.
  • Emulsifies: According to Jaliman, sodium lauryl sulfate can help to bind two ingredients together, such as oil and water, to prevent separation in the formula.
  • Fights bacteria: Jaliman says it also has some antibacterial and antimicrobial properties.

Sodium Lauryl Sulfate vs. Sodium Laureth Sulfate

Two sulfates that commonly occur in beauty products (either separately or together) are sodium lauryl sulfate and sodium laureth sulfate (SLES). Because of the slight variation in spelling, these ingredients are easy to confuse, but there is a notable difference between the two. They function similarly in the sense that both ingredients create that foamy feel in products, but as Fu explains it, sodium lauryl sulfate binds to proteins on the skin's surface more than sodium laureth sulfate. What this means is that sodium lauryl sulfate has the potential to be more irritating and there's a higher rate of contact allergy to it: "In terms of irritation potential of a product, sodium laureth sulfate is a better alternative than sodium lauryl sulfate," Fu says.

Side Effects of Sodium Lauryl Sulfate

Nazarian says although sodium lauryl sulfate is not a bad ingredient for most people, it can, in fact, be an irritant. "If you're going to get it in your eyes or if you’re not going to wash it off your skin and you’re going to leave some of the residue on your skin, it can be irritating," Nazarian says. But Lu adds that the potential for irritation is mostly based on the concentration of sodium lauryl sulfate. "The higher the concentration, the higher the potential of irritation," Lu says.

Nazarian and Jaliman advise anyone with a true allergy as well as those with sensitive skin or eczema (since it may strip a little more oil than required) to avoid using sodium lauryl sulfate in their skincare products. However, both dermatologists say other skin types should be fine using it if they want to, and Lu adds that these people don't need to swear off sulfates altogether. "Generally, for all other skin types, we wouldn’t go as extreme as recommending to avoid all sulfates, because it’s still possible to create a good, non-stripping formula that contains sulfates," Lu says.

As far as allergies go, Nazarian says when a patient comes in with a potential contact allergy, sodium lauryl sulfate is one of the ingredients that they will test for, but it's more of an irritant than it is an allergy. "Anything can be an irritant if it’s used the wrong way or if it’s on the skin too long," she explains. "It’s more likely to be an irritant, meaning we just need to teach people how to use it and how often to use it."

How to Use It

If you're one of the ones left standing who doesn't have an allergy, sensitive skin, or atopic dermatitis and loves the feel of a rich lather too much to give it up, heed the below advice when using products containing sodium lauryl sulfate to avoid irritation down the line.

To properly use a sodium lauryl sulfate cleaner, first, get your skin wet. Applying a surfactant to dry skin will likely only increase the risk of irritation, so dilute it with lukewarm water. Then, apply the body wash and rinse it off right away. Jaliman and Nazarian say that leaving the product on your skin for too long can also lead to irritation, so keep your showers brief. Nazarian says it's okay to bathe and use a product containing sodium lauryl sulfate every day, but she adds that it's important to only apply the product to the bacteria-harboring areas that actually need a deep clean (armpits, groin, and feet) and skip other areas, like your legs, to avoid stripping too much oil.

She also recommends skipping your face and opting for something gentler. "Sometimes the cleansers that we use for the face are a little bit more aggressive than they need to be," Nazarian explains. "You’re much more likely to strip too much oil off of your face than you are your scalp or even your back."

And lastly, because sodium lauryl sulfate can be drying or irritating, Jaliman suggests finishing with a moisturizer right after you get out of the shower to restore your skin.

The bottom line? "The issue isn’t always what they’re using to clean," Nazarian says. "It’s how they're cleaning. Even a tool that is not necessarily a dangerous tool used the wrong way will cause problems."

Up next: 15 Sulfate-Free Shampoos That Won't Strip Your Hair

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