what is sls

Is SLS Bad? What to Know About Sodium Lauryl Sulfate

Is sodium lauryl sulfate bad? Discover common SLS products, potential effects, & how to avoid them by switching to natural home and personal products.

Is sodium lauryl sulfate bad? Discover common SLS products, potential effects, & how to avoid them by switching to natural home and personal products.

Sulfates are effective cleaning ingredients that remove dirt and oil from a wide variety of surfaces. But over the past few decades, consumers have begun questioning their safety – especially sodium lauryl sulfate (SLS). So what’s the deal with the negative hype? Is this ingredient bad?

What Is SLS?

SLS is the best-known and most commonly-used sulfate. It’s inexpensive and can be derived from a number of sources including petroleum, coconut oil, and even palm oil. It’s an effective surfactant, a substance in detergents that combines with liquid to reduce surface tension, acting as wetting and foaming agents in cleaning products.

Where is SLS Used?

This surfactant can be found in the following cleaning, personal care, and cosmetic products.

Fun Fact: Certain food products also use this ingredient as a thickening agent.

Common Concerns Related to SLS

How safe are these ingredients in regards to common health and skin concerns

  • Skin, Eye, Lung Irritation: Moderate risk
  • Cancer: low risk
  • Allergies & Immunotoxicity: low risk
  • Developmental and Reproductive Toxicity: low risk
  • Use Restrictions: low risk

SLS vs SLES: Are they the Same?

In short, SLES (Sodium Laureth Sulfate) are a gentler surfactant compared to SLS and are found to be less likely to irritate skin and eyes.

Two Different Chemical Formulas

Although they sound similar – and they’re often used in the same types of products – SLS and SLES are two separate surfactants with two different chemical formulas:

SLES = CH3(CH2)11(OCH2CH2)nOSO3Na,

SLS = CH3(CH2)11SO4Na.)

SLES is derived from SLS through ethoxylation, when ethylene oxide is introduced to make it less drying and more gentle than SLS. The problem: Ethoxylation can create trace amounts of 1,4- dioxane.

The FDA acknowledges that 1,4- dioxane is a possible carcinogen. In fact, since the 1980’s, the agency has monitored the risks of 1,4- dioxane and the use of it in certain consumer goods. If it finds its presence in cosmetics poses a health hazard, the FDA will take steps to regulate its use and notify the public accordingly.

Other Popular Sulfates

Sodium lauryl sulfate is just one member of the sulfate family. Other popular sulfates include:

  • sodium laureth sulfate (e.g. SLES, sodium lauryl ether sulfate)
  • ammonium laureth sulfate (ALS)
  • sodium stearyl sulfate
  • sodium lauryl sulfoacetate
  • sodium coco sulfate

Is Sodium Lauryl Sulfate Safe?

For every report that claims that this ingredient is harmful, another one says the opposite. If you don’t know what to think, you’re not alone.

The World Health Organization (WHO), however, has detailed several warnings about SLS. It reports potential harm if swallowed, as well as eye, skin, and respiratory irritation.

The National Institutes of Health (NIH) concluded that, although “years of anti-SLS campaigns have led to consumer concerns and confusion regarding the safety of SLS,” sodium lauryl sulfate isn't a danger to human health – as long as it's formulated correctly.

Is SLS Safe for Skin?

The International Journal of Toxicology reported that SLS wasn't harmful as long as it:

  • was used for short periods of time
  • was thoroughly rinsed off of skin
  • didn't exceed a concentration of 1%.

According to the NIH report (referenced above), sodium lauryl sulfate concentrations of more than 2% can cause skin irritation. But the concentration of SLS in household cleaning products can vary from 1% to 30%. In personal care products (like bubble baths and body washes), SLS concentrations can range even higher.

This surfactant in body wash and cleansers is effective at removing dirt and grease, but there’s a tradeoff. Dr. Julie Jackson, MD, FAAD says, “To remove impurities, SLS also strips away some of the skin’s natural moisturizing oils.”

At the time of publication, more work was required to determine the effects of repeated, low-dose exposure. However, exploratory research indicates that exposure to a high concentration of SLS can cause skin barrier disruption (due to altered skin maturation).

Is SLS Safe for Hair?

Because it creates rich foam that’s easily rinsed away, it's common to find this surfactant in shampoo and other hair care products. But because it’s such a powerful cleanser, this ingredient can easily remove too much of the natural sebum on the scalp, causing flaking while making hair feel harsh and dry.

Is SLS Safe for the Environment?

Learn more about this ingredient and its effects on aquatic life and bioaccumulation.

SLS and Aquatic Life

Since this surfactant in its raw form is moderately toxic to aquatic life, the WHO warns that it shouldn't be allowed to enter the environment. Most dilutions of this ingredient aren’t necessarily toxic, but this depends on the marine species, water hardness, and water temperature.

That this ingredient enters the water stream from personal care products is a significantly diluted form that can be considered non-toxic (due to its low concentration). However, it has been suggested that chronic toxicity can also occur at low concentrations.

Biodegradability and Bioaccumulation

SLS is biodegradable and has low potential for bioaccumulation, but since it can still be detected in the environment, further monitoring is still being done.

What Are Sulfates?

Derived from petroleum or plant-based sources, sulfates create rich lather and help cleaning products as a surfactant to lift, dissolve, and rinse impurities away.

These ingredients lower the surface tension of water so oil, dirt, and grime can mix with it more easily. One side of the molecule attaches to oil while the other side attaches to water. Sulfates have been in use since the 1930s since these sulfur-containing mineral salts are cheap for companies to produce. 

Commonly Found Sulfates

Sulfates can commonly be found in face wash, shampoo, body wash, and even toothpaste. They include:

  • Magnesium Sulfate
  • Copper Sulfate
  • Lead Sulfate
  • Gypsum
  • Sodium Sulfate
  • Iron Sulfate
  • Hydrogen Sulfate
  • Calcium Sulfate
  • Ammonium Laureth.
  • Ammonium Xylenesulfonate.
  • Ethyl PEG-15 Cocamine Sulfate 

Why Puracy Products Are Sulfate-Free

Cleaning and personal care products should always consider the health of people, pets, and the environment. That’s why we’re one of a handful of companies that utilizes coco glycinate. This natural sodium lauryl sulfate alternative produces the rich, satisfying lather in foaming body care products (like our Puracy Natural Body Wash).

Puracy was founded on full transparency so you’ll never have to wonder if our products are safe for your family and home: They are and always will be.

The 30 Days of Cleaning with Puracy