Sodium Lauryl Sulfate 35%

Sodium Lauryl Sulfate 35% — Technical & Performance Overview

Sodium Lauryl Sulfate (SLS) is an anionic surfactant derived from lauryl alcohol, commonly sourced from coconut or palm kernel oil, and neutralized with sodium hydroxide. Supplied as a 35% active aqueous solution, it appears as a clear to slightly hazy liquid with high foaming capacity and excellent detergency. Sodium Lauryl Sulfate is widely used in personal care, household, and industrial formulations where effective cleansing, emulsification, and soil removal are required.

The manufacturing process involves sulfation of lauryl alcohol followed by neutralization, resulting in a highly efficient surfactant with consistent performance. While SLS is not ethoxylated and does not contain parabens or formaldehyde donors, it is classified as a strong cleanser and is typically used in rinse-off applications or in controlled concentrations within blended surfactant systems.

In personal care formulations, Sodium Lauryl Sulfate functions primarily as a primary surfactant and foaming agent. It provides rapid wetting, strong oil and particulate removal, and rich foam generation. Due to its high cleansing power, it is most commonly used in shampoos, body washes, facial cleansers, toothpastes, and hand soaps, often in combination with milder co-surfactants to improve skin feel and reduce irritation potential.

From a safety and regulatory perspective, Sodium Lauryl Sulfate has a long history of global use and broad regulatory acceptance when formulated appropriately. While it may cause irritation at higher concentrations or with prolonged skin contact, it is considered safe in rinse-off applications and controlled leave-on systems when used within recommended limits and properly balanced formulations.

Ingredient Identification

INCI Name: Sodium Lauryl Sulfate
CAS Number: 151-21-3
Active Matter: 35% (aqueous solution)

Physical & Technical Properties

• Appearance: Clear to slightly hazy liquid

• Odor: Mild, characteristic

• Solubility: Completely soluble in water

• pH (as supplied): Typically 7.5–9.5

• Functional Role: Primary anionic surfactant, cleanser, foaming agent

Typical Usage Levels (Personal Care)

• Shampoos & Body Washes: 5–15% (as supplied, depending on desired cleansing strength)

• Facial Cleansers: 1–5% (typically blended with milder surfactants)

• Hand Soaps: 5–12%

• Toothpaste: 0.5–2.0% (foam generation)

Actual usage levels depend on formulation type, surfactant system design, and irritation mitigation strategy.

Formulation Compatibility & Common Combinations

Sodium Lauryl Sulfate is commonly formulated with:

• Amphoteric surfactants (e.g., Cocamidopropyl Betaine) to reduce irritation

• Nonionic surfactants for foam stability and mildness

• Thickeners (e.g., sodium chloride, polymeric rheology modifiers)

• Conditioning agents to improve after-feel in rinse-off systems

SLS is typically added to the water phase with gentle mixing to minimize excessive aeration. Viscosity and mildness are optimized through surfactant blending and electrolyte adjustment.

Regulatory & Safety Notes

Regulatory Status: Approved for use globally in cosmetic and personal care products within concentration guidelines

California Proposition 65: Not listed

EWG Context: Generally rated higher concern due to irritation potential; commonly restricted to rinse-off applications

Irritation & Sensitization: May cause skin or eye irritation at higher concentrations; formulation balancing is recommended

Clean Beauty Compatibility: Limited; often excluded from “clean” or sensitive-skin standards but remains acceptable in conventional and performance-driven formulations