Sodium Lauryl Sulfates

• Unveiling the Harms of Sulfates in Skincare: A Closer Look at SLS

  Skincare routines often involve cleansing agents to maintain skin health (Gillaizeau et al., 2021). One common ingredient found in many cleansers is Sodium Lauryl Sulfate (SLS), a surfactant (or detergent) known for its foaming and cleansing properties. Surfactants bind to oil, grease, and dirt, pulling them away from the surface while creating that nice foamy lather. While SLS is widely used, recent research sheds light on its potential harms, raising concerns about its impact on skin physiology and the skin bacterial community.

• Disruption of Skin Barrier Function:

  SLS, along with other synthetic surfactants, has been shown to disturb the composition of skin lipids, leading to the removal of lipids from the stratum corneum, or the top layer of skin (Gillaizeau et al., 2021). This disruption compromises the skin barrier function, which is crucial for protecting the skin. The removal of lipids contributes to increased Transepidermal Water Loss (TEWL), leading to a decrease in the natural moisturizing factor (NMF) of the skin. More simply put, SLS's can result in skin dryness and decreased skin moisturization.

• Skin Irritation and Redness:

  Studies confirm that the application of SLS patches induces skin barrier dysfunction, causing a significant increase in TEWL (Gillaizeau et al., 2021). The skin's redness also intensifies, highlighting the potential for irritation. Moreover, the study reveals a decrease in skin luminosity after SLS patch application, indicating a broader impact on skin appearance and health.

• Effects on Skin Bacterial Communities:

  Beyond the well-documented effects on skin barrier and irritation, limited knowledge exists on how SLS affects the skin's bacterial community (Gillaizeau et al., 2021). Research indicates that SLS patches lead to significant changes in the composition of skin bacteria. After SLS application and skin barrier disruption, there is an increase in the richness of bacteria, with some potentially pathogenic genera showing a rise in abundance.

• Shifts in Skin Microbiota:

  The relative abundance of Firmicutes phylum and the Staphylococcaceae family significantly increases after SLS patch application (Gillaizeau et al., 2021). While an increase in Staphylococcaceae may include resident commensal species beneficial to skin health, it could also create a favorable environment for opportunistic pathogens like Staphylococcus aureus. The decrease in major resident skin microbiota, including Cutibacterium, Micrococcus, and Corynebacterium, suggests a disturbance that could compromise skin protection and repair mechanisms.

• Preserving Skin Health:

  Considering the potential harms associated with SLS, it becomes crucial to reassess skincare habits. Redefining hygiene practices by opting for cleansers with lower detergent concentrations and milder surfactants can help minimize the impact on skin integrity, physiology, and the bacterial community microbiome. This shift towards gentler skincare choices aims to maintain a balanced and beneficial interaction between the skin and its microbial inhabitants.

In an era where allergies and skin conditions are on the rise, understanding the implications of skincare ingredients like SLS becomes so important. By making informed choices and prioritizing skin health over harsh cleansing practices, individuals can contribute to maintaining the delicate balance of the skin's microbiota for overall well-being.

Where should I look for sulfates?

Sodium Lauryl Sulfate (SLS) is a versatile and widely used surfactant that finds applications in various personal care and household products due to its excellent foaming and cleansing properties. Some common uses of SLS include:

1. Shampoos and Conditioners:

   • SLS is a key ingredient in many shampoos and conditioners, providing the foaming action that helps distribute the product through the hair and scalp.

2. Body Washes and Shower Gels:

   • SLS is included in body washes and shower gels to create a rich lather and enhance the cleansing experience.

3. Facial Cleansers:

   • Many facial cleansers, including those for removing makeup, contain SLS to aid in the removal of dirt, oil, and impurities from the skin.

4. Toothpaste:

   • SLS is used in toothpaste to create a foaming action, assisting in the distribution of the toothpaste throughout the mouth during brushing.

5. Hand Soaps:

   • Liquid hand soaps often contain SLS for its cleansing and foaming properties, providing an effective way to clean hands.

6. Bath Products:

   • SLS is commonly found in various bath products, such as bath bombs and bath salts, to create a foaming and cleansing effect in the bathwater.

7. Shaving Creams:

   • Some shaving creams and foams include SLS to generate a lather that helps the razor glide smoothly across the skin.

8. Dishwashing Detergents:

   • SLS is used in dishwashing detergents to break down grease and facilitate the cleaning of dishes.

9. Laundry Detergents:

   • In laundry detergents, SLS assists in the removal of stains and dirt from fabrics by enhancing the detergent's cleaning action.

10. Cleaning Products:

    • SLS is found in various household cleaning products, such as all-purpose cleaners and surface cleaners, due to its effective cleaning capabilities.

Be Careful!

Yes, sulfates can sometimes be listed under different names in ingredient lists. Consumers need to be aware of these alternative names to identify sulfates in products. Here are some common alternative names for sulfates:

1. Sodium Lauryl Sulfate (SLS):

   • Sodium Lauryl Sulphate

   • Sodium dodecyl sulfate

   • Sulfuric acid, monododecyl ester, sodium salt

   • Sodium salt sulfuric acid

   • Monododecyl ester sodium salt sulfuric acid

2. Sodium Laureth Sulfate (SLES):

   • Sodium Lauryl Ether Sulfate

   • Sodium laureth-2 sulfate

   • Sodium lauryl ethoxysulfate

   • Sodium lauryl ether sulfate

It's important to carefully read ingredient labels and look for these terms if you are trying to avoid sulfates in your personal care or household products. Keep in mind that some products may also be labeled as "sulfate-free" if they do not contain sulfates, offering an easier way for you to find alternatives.

References:

Gillaizeau, F., Leuillet, S., Douillard, B., Carton, T., De Martino, A., Moussou, P., & André, V. (2021). Effect of Sodium Lauryl Sulfate (SLS) Applied as a Patch on Human Skin Physiology and Its Microbiota. Cosmetics, 8(1), 6. https://doi.org/10.3390/cosmetics8010006