Steareth-20 is an ester of polyethyleneglycol and stearic acid, which is identified by the CAS number 9005-00-9. This substance is characterised by a number of unique properties that make it readily used in cosmetic formulations, mainly as a base ingredient. It is most commonly found as an O/W emulsifier, which enables the formation of emulsions.
The chemical compound with the INCI name of Steareth-20 is a non-ionic surfactant. It dissolves very well in water, oil and in ethanol as well. This substance undergoes hydrolysis.
As regards the physical properties of Steareth-20, it is a waxy solid. It is characterised by its white or cream colour and lack of odour and taste. It is a hygroscopic compound, which means that it absorbs moisture from the air. Therefore it should be stored in a sealed container. The melting point of Steareth-20 ranges from 55 to 60 oC. It is stable under a variety of conditions and does not break down when stored properly.
Steareth-20 is characterised by its excellent emulsification capacity. It is readily used as an emulsifier that mediates between the oil phase and the water phase to stabilise and maintain an even distribution of the substance. It will work well with both fatty and aqueous ingredients. It is used in different types of lotions, creams, conditioners and cosmetic and pharmaceutical emulsions.
This substance has excellent washing and wetting properties. This facilitates contact between the washing solution and the surface to be washed as well as the removal of dirt from the hair or skin. In addition, Steareth-20 can be used to stabilise foam and improve foam quality in products such as shampoos, gels and soaps.
This compound can also act as a rheology modifier in washing cosmetics. Thanks to its properties, it improves the consistency of the product while increasing its viscosity.
Steareth-20 can also be found in, e.g., cosmetic make-up products (such as eye shadows, powders, mascaras), deodorants, toothpastes and shaving creams.
According to a 2012 report drawn up by Cosmetic Ingredient Review experts, Steareth-20 is safe for use in cosmetic products. However, manufacturers should maintain the correct proportions in compositions. This substance can boost the intensity of other ingredients in a given preparation on the skin, so they should be selected with attention.
According to chemical regulations, Steareth-20 as a pure substance is also classified as safe. According to available sources, the compound has been shown to be non-allergenic when used correctly, but bear in mind that the human body may react differently in certain cases. Therefore, especially with sensitive skin, it is advisable to check the product label carefully and carry out additional sensitisation tests.
