Polyethylene glycol—commonly referred to as PEG—is an ingredient many people apply to their skin daily without realizing it. PEGs are widely used in personal care and cosmetic products, including moisturizers, anti-ageing creams, conditioners, shampoos, body washes, sunscreens, make-up, hair dyes, and bleaching products.
While PEGs play functional roles in product formulation, growing consumer awareness around ingredient safety and long-term exposure has led many people—especially those seeking toxin-free skincare—to question whether PEGs truly align with clean beauty values.
What Is PEG and Why Is It Used?
PEGs are petroleum-derived compounds created by reacting ethylene oxide with water. In cosmetic formulations, PEGs are commonly used to:
Improve texture and spreadability – makes creams, lotions, and gels easier to apply and feel smooth on the skin.
Act as thickeners and stabilisers – maintain product consistency and prevent ingredients from separating over time.
Function as emulsifiers – help oil- and water-based ingredients blend evenly and remain stable.
Retain moisture – act as humectants, drawing water into the skin to help maintain hydration.
Enhance skin penetration – increase absorption of other ingredients into the skin.
Solubilize ingredients – help dissolve certain oils, fragrances, or actives that otherwise wouldn’t mix well in a formula.
Serve as carriers for actives – in some formulations, PEGs help deliver vitamins, antioxidants, or other active ingredients evenly throughout the product.
One of PEG’s defining characteristics is its role as a penetration enhancer, meaning it helps other ingredients absorb more easily into the skin.
On ingredient labels, PEGs usually appear as “PEG-” followed by a number (such as PEG-40 or PEG-100), which indicates the compound’s molecular weight or the number of ethylene glycol units used in its production.
The Contamination Concern: What’s Not on the Label
One of the most significant concerns surrounding PEGs is not always the ingredient itself, but how it is manufactured.
During the ethoxylation process, PEGs can become contaminated with potentially harmful by-products, including:
1,4-Dioxane – classified by the International Agency for Research on Cancer (IARC) as a possible human carcinogen
Ethylene oxide – classified as a known human carcinogen
Importantly, 1,4-dioxane does not appear on ingredient labels, making it invisible to consumers. While cosmetic regulations limit these contaminants, trace amounts may still be present unless the ingredient undergoes extensive purification.
This lack of transparency is one reason PEGs are often excluded from toxin-free and clean skincare formulations.
Skin Absorption and Increased Exposure
PEGs are known to increase skin permeability. While this improves product performance, it may also increase the absorption of other ingredients within the formula.
If a product contains synthetic fragrances, preservatives, or potentially irritating chemicals, PEGs can unintentionally help deliver those substances deeper into the skin.
This may be especially relevant for:
Compromised or broken skin
Sensitive or reactive skin
Babies and children
Long-term, daily use of leave-on products
Potential Health Considerations
Scientific research continues to evolve, and regulatory bodies allow PEGs in cosmetics within set limits. However, some researchers and clean-beauty advocates raise concerns about long-term and cumulative exposure, particularly when PEGs are used frequently and across multiple products.
Concerns often cited include:
Skin irritation and increased sensitivity
Enhanced absorption of harmful substances
Potential hormone-disrupting effects (indirectly, through increased chemical exposure)
Fertility-related concerns linked to ethylene oxide contamination
Evidence-Based Research on PEGs and Ingredient Safety
Below are authoritative sources that provide insight into PEGs, their manufacturing by-products, and safety considerations. These references reflect the scientific basis behind questions that many toxin-free skincare advocates raise, and they can help you make more informed choices about ingredients and product formulation.
International Agency for Research on Cancer (IARC) – Monographs on the Evaluation of Carcinogenic Risks to Humans
IARC classifications identify ethylene oxide as a known human carcinogen and 1,4-dioxane (a potential contaminant in ethoxylated ingredients) as a possible carcinogen, underscoring concerns about trace contaminants generated during PEG production.U.S. Food and Drug Administration (FDA) – Guidance on 1,4-Dioxane in Cosmetics
The FDA acknowledges that 1,4-dioxane can occur as an unintended by-product of ethoxylation, and while it is not required to be listed on labels, the agency monitors its presence and encourages minimisation.U.S. Environmental Protection Agency (EPA) – Technical Fact Sheets on Cosmetic By-Products
EPA toxicology profiles and fact sheets provide health and environmental evaluations of chemicals like 1,4-dioxane and ethylene oxide, reinforcing scientific context around their hazards.Cosmetic Ingredient Review (CIR) Expert Panel – Safety Assessment of Polyethylene Glycols
The CIR panel evaluates cosmetic ingredients permitted in the U.S. market. Their assessment supports the safety of properly formulated PEGs but highlights issues related to increased penetration and potential contaminants, which informs many toxin-free formulations.European Chemicals Agency (ECHA) – Harmonised Classification and Labelling
ECHA assessments categorise ethylene oxide as a carcinogen and mutagen under EU regulation, emphasising precautionary concern for substances that may be involved in PEG production.
The Bottom Line
PEGs are common, functional, and legally permitted in cosmetics—but common does not always mean optimal.
For those seeking toxin-free skincare, avoiding PEGs is a conscious step toward reducing unnecessary chemical exposure and choosing formulations that honour both skin health and long-term wellbeing.
At Green Cosmetica, beauty is not about excess—it’s about clean, thoughtful simplicity you can trust 🌿. That’s why we don’t use PEGs in our formulations and instead choose Olivem® 1000, a naturally derived, olive-oil-based emulsifier that gently blends ingredients, supports the skin barrier, and keeps our products toxin-free and safe for daily use.