Sodium Isethionate

Sodium isethionate is primarily a mild anionic surfactant/cleansing agent used in rinse-off cleansers and syndet bars, where it is generally well-tolerated at typical use levels. Clinical and practical experience place it among gentler surfactants than SLS, but as a detergent it can still disrupt barrier lipids and provoke stinging or dryness in eczema-prone or highly compromised skin, especially with frequent use or hot water. Given sensitive-skin populations and cumulative surfactant exposure in routines, it fits best as “gentle” rather than “very gentle.” Safety Notes: In consumer products, sodium isethionate is most commonly used as a mild anionic surfactant in rinse-off cleansing systems (facial/body cleansers, syndet bars, shampoos), where finished-formula levels can start around ~0.1–1% in very low-foam co-surfactant or “mildness” blends. At the high end, syndet/solid cleanser formats and concentrated surfactant bases sold to consumers can contain very large fractions of SCI-derived surfactant solids, with finished bars or paste cleansers reaching ~30–50% sodium isethionate. It is rarely used in leave-on skincare except at very low levels (typically ≤1%) due to surfactant/irritancy and sensorial constraints.