In the world of surfactants, Sodium Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES) are two of the most common and effective cleaning agents. While both are anionic surfactants and share many similarities in terms of detergency and foaming, there’s a crucial difference that makes SLES 70% a preferred choice for many formulators, particularly in personal care and sensitive cleaning applications: its milder nature. This article explores these differences, providing formulators with insights to make informed decisions.

Understanding the Molecular Difference: Ethoxylation is Key

The fundamental difference between SLS and SLES lies in the manufacturing process. SLS is produced by directly sulfating lauryl alcohol. SLES, on the other hand, is produced by first reacting lauryl alcohol with ethylene oxide in a process called ethoxylation. This adds polyoxyethylene chains to the alcohol. The resulting ethoxylated alcohol is then sulfated. The addition of these ethylene oxide units:

  • Increases the molecule's size: A larger molecule is less likely to penetrate the stratum corneum (the outermost layer of the skin).
  • Reduces the charge density: This contributes to a less aggressive interaction with skin proteins and lipids.

These modifications make SLES inherently milder than SLS, resulting in lower potential for skin and eye irritation.

Performance Comparison: Detergency, Foaming, and Mildness

Both SLS and SLES are excellent detergents and foaming agents. However, when it comes to mildness:

  • SLS: Known for its potent cleansing power and high foaming ability. However, it can be a significant skin and eye irritant, especially at higher concentrations or with prolonged contact. Formulators often need to balance its efficacy with other ingredients to mitigate potential irritation.
  • SLES 70%: Offers comparable detergency and foaming properties to SLS but with significantly reduced irritation potential. This makes it ideal for products that remain on the skin (leave-on products) or are used frequently, such as shampoos, body washes, and facial cleansers. The 70% grade typically refers to the active matter content, which is a standard commercial form.

Applications Where SLES 70% Shines:

Given its milder profile, SLES 70% is the surfactant of choice for:

  • Personal Care Products: Shampoos, conditioners, body washes, facial cleansers, bubble baths, hand soaps, and even some baby products.
  • Gentle Household Cleaners: Dishwashing liquids and laundry detergents where skin contact is common.
  • Products for Sensitive Skin: Formulations specifically designed for individuals with sensitive skin or conditions like eczema benefit greatly from the reduced irritation of SLES.

When Might SLS Still Be Considered?

SLS might be chosen in specific industrial cleaning applications where maximum detergency is required and skin contact is minimal, or where its cost-effectiveness is the primary driver and formulation modifications can manage irritation. However, for consumer-facing products, the trend is strongly towards milder alternatives like SLES.

Choosing a Supplier for Your Needs

As formulators increasingly prioritize mildness and consumer safety, sourcing high-quality SLES 70% from reputable manufacturers is crucial. Look for suppliers who can guarantee low levels of impurities, consistent active matter, and reliable supply. Understanding the nuances between SLS and SLES empowers you to create superior products that meet market demands. We invite you to explore our range of SLES 70% and consult with our team to determine the best surfactant solution for your formulation needs.