Ingredient review
PEG-115M
INCI: PEG-115M
PEG-115M is a gentle synthetic thickener that gives products a smooth, silky feel without clogging pores or causing irritation.
In plain English
PEG-115M is a type of polyethylene glycol with a very large molecular size. In skincare, it acts like a thickening agent, making lotions and creams feel richer and more luxurious. Because its molecules are too large to penetrate the skin, it stays on the surface, providing a smooth, non-greasy finish. It also helps other ingredients spread evenly and can form a light film that temporarily holds moisture against the skin.
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-115M 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-115M.
- 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-115M is a synthetic polymer derived from ethylene glycol, with an average molecular weight of about 115,000 Daltons. It belongs to the PEG family, which are widely used in cosmetics for their water-solubility and mildness.
How it works
When added to a water-based formula, PEG-115M dissolves and its long chains entangle, increasing the product's viscosity. This creates a thicker, more stable texture. Upon application, it leaves a thin, flexible film on the skin that can reduce water loss (transepidermal water loss, or TEWL) and improve the feel of the product.
Pros
Gentle on skin
PEG-115M has a very low irritation and comedogenic rating, making it suitable even for sensitive and acne-prone skin types.
Improves product feel
It gives creams and serums a smooth, silky texture that spreads easily and leaves a pleasant, non-sticky finish.
Cons and cautions
Synthetic origin
As a synthetic polymer, it may not appeal to those seeking all-natural or organic skincare formulations.
Limited active benefit
PEG-115M is primarily a texture enhancer and does not provide direct antioxidant, anti-aging, or moisturizing benefits on its own.
Best for
- Anyone looking for a lightweight, non-greasy thickener in their products
- People with sensitive or acne-prone skin who want to avoid heavy oils
Use caution if
- Those who prefer completely natural or plant-derived thickeners
Usage tips
Safety summary
PEG-115M is considered safe for topical use. Its large molecular size prevents skin penetration, and it has a low potential for irritation or allergy. No significant safety concerns have been reported in cosmetic use.
Research notes
Studies on PEGs indicate low toxicity and irritation. High-molecular-weight PEGs are not absorbed through intact skin. The Cosmetic Ingredient Review (CIR) panel has deemed PEGs safe for use in cosmetics at typical concentrations.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission. PEG compounds are generally recognized as safe when used as intended.
- Common uses
- Serums, Creams, Lotions, Gels, Masks
- Environmental note
- PEGs are synthetic and may not be biodegradable in all environments. However, high-molecular-weight PEGs like PEG-115M are less likely to be absorbed by aquatic life.
Good to know
- PEG-115M is not absorbed into the skin due to its large molecular size.
- It is often used in gel-based masks and leave-on treatments for a luxurious feel.
Common questions
What is PEG-115M in beauty products?
PEG-115M is a type of polyethylene glycol with a very large molecular size. In skincare, it acts like a thickening agent, making lotions and creams feel richer and more luxurious. Because its molecules are too large to penetrate the skin, it stays on the surface, providing a smooth, non-greasy finish. It also helps other ingredients spread evenly and can form a light film that temporarily holds moisture against the skin.
What does PEG-115M do in a beauty product?
When added to a water-based formula, PEG-115M dissolves and its long chains entangle, increasing the product's viscosity. This creates a thicker, more stable texture. Upon application, it leaves a thin, flexible film on the skin that can reduce water loss (transepidermal water loss, or TEWL) and improve the feel of the product.
Is PEG-115M safe for most people?
PEG-115M is considered safe for topical use. Its large molecular size prevents skin penetration, and it has a low potential for irritation or allergy. No significant safety concerns have been reported in cosmetic use.
Who should be careful with PEG-115M?
Those who prefer completely natural or plant-derived thickeners
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.