Sulphates, chemically anionic surfactants in the alkyl sulphate family, are the most commonly used cleansing class in cosmetic formulas because of their foaming and oil-removing abilities. Familiar members include:
- Sodium Lauryl Sulfate (SLS): Strong oil removal, abundant foam and a harsher cleansing profile.
- Sodium Laureth Sulfate (SLES): An ethoxylated derivative of SLS with a gentler profile, more common in modern formulas.
- Ammonium Lauryl Sulfate (ALS): A similar profile to SLS, with comparable harshness.
SLS and SLES: Not the Same Thing
Sulphate-free marketing groups all sulphates into one category, but SLS and SLES have different contexts in cosmetic formulation. Through ethoxylation, SLES provides a gentler cleansing profile; it is the preferred form in most modern shampoos.
Sulphate-free formulas often favour gentler amphoteric or zwitterionic surfactants such as Cocamidopropyl Betaine, Coco-Glucoside and Sodium Cocoyl Isethionate.
Which Profiles May Need Extra Care?
Sulphates may require extra care on sensitive or barrier-compromised skin and on a scalp prone to dandruff or irritation. Studies of SLS, particularly at high concentrations, show effects on barrier function. On oily or normal skin and a healthy scalp, however, they may be comfortably tolerated in modern formulas.
- Sensitive or atopic skin: A sulphate-free or gentle surfactant profile may be a suitable starting point in this context.
- Sensitive scalp or dandruff: A low-sulphate or alternative cleansing profile may be considered in the scalp context.
- Colour-treated hair: Sulphate-free formulas are often preferred in the context of colour protection.
- Oily or normal hair and skin: Modern SLES formulas may be comfortably tolerated by most profiles; there is no requirement to choose sulphate-free.
Marketing and Science
The sulphate debate has become part of clean beauty marketing in recent years. Cosmetic formulation literature, however, indicates that sulphates should be assessed in the context of the profile, not subject to a blanket prohibition.
What matters is concentration, the formula's overall cleansing profile, frequency of use and the user's context.
Three Practical Reminders
- Label order matters. A sulphate near the top is a main cleanser; lower down, it is an additional component.
- The washing context matters. In quickly rinsed products such as shampoo and cleansers, the effect remains partial; sulphates are not expected in leave-on products such as creams and serums in the first place.
- The profile context matters. For a sensitive profile, considering alternative cleansers may help; healthy profiles may comfortably tolerate modern sulphate formulas.
This article is for information only; it does not provide a medical diagnosis, treatment or a guarantee of safety. If you have sensitivities, are pregnant or have particular circumstances, you are advised to discuss your decisions with your own doctor.