Magnesium Laureth Sulfate

Magnesium laureth sulfate is an anionic surfactant used mainly in rinse-off cleansers (often a few percent up to ~10%+ active surfactant), and surfactants are a well-established cause of irritant contact dermatitis via lipid/protein disruption of the stratum corneum. While the magnesium salt and ethoxylation can make it somewhat milder than sodium lauryl sulfate, clinical experience and patch/usage data still show meaningful irritation risk in eczema-prone and highly sensitive skin—especially with frequent cleansing or compromised barriers. Given real-world cumulative exposure in routines and the population of reactive patients, I rate it as moderate with patch testing advised. Safety Notes: Magnesium laureth sulfate is primarily used as an anionic primary surfactant in rinse-off cleansers (shampoos, body washes, facial cleansers), where it can appear at low levels (~0.5–3%) as a secondary cleanser/foam booster alongside other surfactants or in very mild formulas. In mainstream rinse-off products it is commonly ~5–15% active, while high-foaming/high-cleansing consumer shampoos and clarifying washes can reach ~20–25% active surfactant load; leave-on products are uncommon and typically kept very low due to irritation potential.