Steareth-21

Steareth-21 is a non-ionic surfactant derived from stearic acid (a naturally occurring fatty acid) combined with polyethylene glycol. It belongs to a group of ingredients known as ethoxylated alcohols, which are widely used in skincare and cosmetic formulations.In skincare products, steareth-21 primarily functions as an emulsifier—helping oil and water-based ingredients blend together—and as a mild cleanser. It is mild enough for everyday use and is found in a relatively small proportion of skincare products, typically in cleansers, creams, and lotions.

Steareth-21 works by positioning itself at the boundary between oil and water molecules. One end of its molecular structure is attracted to oils, whilst the other is attracted to water, allowing these normally incompatible ingredients to mix smoothly.As a cleanser, it surrounds oil and dirt particles, making them easier to rinse away without disrupting the skin barrier. Because it is a non-ionic (uncharged) surfactant, it tends to be gentler than some alternatives.

Steareth-21 is typically incorporated into formulations by manufacturers rather than used as a standalone product. If you are using a cleanser or cream containing this ingredient, follow the product instructions. There is no need for special handling; simply use as part of your regular routine. If you have very sensitive skin, perform a patch test first, though reactions to this ingredient are uncommon.

Steareth-21 is generally well-tolerated and approved for use in cosmetics across major regulatory bodies. It is unlikely to cause irritation, though as with any ingredient, sensitivity remains possible in isolated cases.