Ingredient review
PEG-45 Stearate
INCI: PEG-45 Stearate
PEG-45 Stearate is a widely used emulsifier that helps create stable, creamy textures, but it may contain trace impurities from its manufacturing process.
In plain English
PEG-45 Stearate is a synthetic ingredient that acts like a bridge between oil and water, allowing them to mix into a smooth, stable cream or lotion. The 'PEG' part stands for polyethylene glycol, a chain-like molecule that helps the ingredient dissolve in water, while 'stearate' comes from stearic acid, a fatty acid that helps it blend with oils. This combination makes it a reliable emulsifier in many moisturizers and cleansers.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-45 Stearate is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging PEG-45 Stearate.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
PEG-45 Stearate is a polyethylene glycol derivative of stearic acid, created through a chemical reaction that attaches 45 units of ethylene oxide to stearic acid. It is a waxy solid at room temperature and is used primarily as an emulsifier in cosmetic formulations.
How it works
In a cosmetic product, PEG-45 Stearate sits at the boundary between oil and water droplets, reducing surface tension so they can mix into a stable emulsion. This prevents the product from separating into oily and watery layers, ensuring a consistent texture and feel every time you use it.
Pros
Reliable emulsifier
PEG-45 Stearate consistently creates stable emulsions, so your cream or lotion won't separate into oil and water layers over time.
Improves texture
It gives products a smooth, creamy feel that spreads easily on the skin without feeling greasy or sticky.
Cons and cautions
Potential trace contaminants
As an ethoxylated ingredient, PEG-45 Stearate may contain trace amounts of 1,4-dioxane, a possible carcinogen, though reputable manufacturers purify it to very low levels.
Not eco-friendly
It is derived from petroleum and is not readily biodegradable, which may be a concern for environmentally conscious consumers.
Best for
- Anyone using standard moisturizers, lotions, or creams
- People who prefer stable, non-separating formulas
Use caution if
- Individuals with known sensitivities to PEG compounds or ethoxylated ingredients
Usage tips
Safety summary
PEG-45 Stearate is generally recognized as safe for cosmetic use at typical concentrations. The main concern is potential contamination with 1,4-dioxane during manufacturing, but reputable suppliers use purification steps to keep levels well below safety limits. Regulatory bodies like the Cosmetic Ingredient Review (CIR) have deemed it safe as used.
Research notes
Studies on PEG-45 Stearate focus on its function as an emulsifier and its safety profile. The CIR Expert Panel reviewed PEG stearates and concluded they are safe for use in cosmetics. Research on 1,4-dioxane indicates that trace amounts are not a significant health risk at the levels found in properly manufactured products.
Common label clues
- Typical concentration
- 1% to 5% of the formula
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission, with no concentration restrictions in most product types.
- Common uses
- Creams, Lotions, Makeup removers, Sunscreens
- Environmental note
- PEG-45 Stearate is synthetic and not readily biodegradable, so it may persist in the environment after washing off.
Good to know
- PEG-45 Stearate is considered safe by major regulatory bodies when used in cosmetics at typical concentrations.
- The number '45' refers to the average length of the PEG chain, which affects its water solubility and emulsifying properties.
Common questions
What is PEG-45 Stearate in beauty products?
PEG-45 Stearate is a synthetic ingredient that acts like a bridge between oil and water, allowing them to mix into a smooth, stable cream or lotion. The 'PEG' part stands for polyethylene glycol, a chain-like molecule that helps the ingredient dissolve in water, while 'stearate' comes from stearic acid, a fatty acid that helps it blend with oils. This combination makes it a reliable emulsifier in many moisturizers and cleansers.
What does PEG-45 Stearate do in a beauty product?
In a cosmetic product, PEG-45 Stearate sits at the boundary between oil and water droplets, reducing surface tension so they can mix into a stable emulsion. This prevents the product from separating into oily and watery layers, ensuring a consistent texture and feel every time you use it.
Is PEG-45 Stearate safe for most people?
PEG-45 Stearate is generally recognized as safe for cosmetic use at typical concentrations. The main concern is potential contamination with 1,4-dioxane during manufacturing, but reputable suppliers use purification steps to keep levels well below safety limits. Regulatory bodies like the Cosmetic Ingredient Review (CIR) have deemed it safe as used.
Who should be careful with PEG-45 Stearate?
Individuals with known sensitivities to PEG compounds or ethoxylated ingredients
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.