PEG-100 stearate works with another ingredient called glyceryl stearate. Together they help stabilise cosmetic products so that they remain well blended.
Where do we get it and how is it made?
PEG-100 stearate and glyceryl stearate are two stearate ingredients. Lush UK purchases a combination of the two from a supplier in Italy.
The word stearate means ester (or salt) of stearic acid. Stearic acid is a fatty substance found in vegetable oils and in this case, in palm and palm kernel oil. To obtain glycol stearate, a chemical reaction is made with glycerine (a by-product of soap making), and to obtain PEG-100 stearate, the materials are transformed using ethylene oxide.
With seven manufacturing sites across the globe, this information may vary depending on where your Lush products were made.
What are the benefits PEG-100 stearate and glyceryl stearate combined?
- It has emulsifying properties that allow oil and water to mix. Creams and lotions are indeed water and oil droplets held together by materials called emulsifiers. Without them, the blend would separate.
- It forms a protective barrier on the surface of the skin and hair, significantly promoting moisture retention.
Is it safe?
PEG compounds of different molecular weights (PEG-6, PEG-40, PEG-100) have been assessed over and over again and are deemed relatively safe for use in cosmetics. Application to the skin poses no risk to human health, has a long history of safe use, and no impact on reproductive health has been found. Interestingly, PEGs are often used in the medical field, including some of the recent COVID-19 vaccines.
However, most ingredient safety data in peer-reviewed scientific publications are based on animal research. We believe these are not good enough to support claims about human safety. For many years, we have partnered with XCellR8 to develop animal-free safety tests. PEG-100 has been classified by this laboratory as having a low risk of genotoxicity. Genotoxicity is the ability of a material to cause damage to the genetic material of cells, which may potentially lead to cancer.
As with many ingredients, a very small portion of the population is sensitive to PEG compounds, especially when ingested, and may develop an allergic reaction. However, for most people, PEGs provide protection and prevent moisture loss when applied to the skin and hair. They also improve skin penetration, allowing the ingredients of a formula to have more effect, but it means that it’s best to avoid using it on open wounds and damaged skin such as children's nappy area.
Is it biodegradable?
PEGs are classified as liquid polymers and are part of a class of water-soluble polymers according to the European Chemicals Agency (ECHA). They are present in the pharmaceutical industry as a biodegradable material, widely used as a laxative. Currently, it does not appear on ECHA’s list of known and potential microplastics.
Safety evaluation of polyethylene glycol (PEG) compounds for cosmetic use
Safety assessment on polyethylene glycols (PEGs)
Intentionally added microplastics in products - final report