Ingredient review
PEG-175 Diisostearate
INCI: PEG-175 Diisostearate
A reliable synthetic emulsifier that helps create stable, creamy textures, but may not suit those avoiding PEG compounds.
In plain English
PEG-175 Diisostearate is a man-made ingredient that helps oil and water mix together in a product so it stays smooth and doesn't separate. It also makes lotions feel thicker and creamier. The 'PEG' part means it's made with polyethylene glycol, a common emulsifier family in cosmetics.
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-175 Diisostearate 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-175 Diisostearate.
- 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
A synthetic polymer made by reacting polyethylene glycol (PEG) with diisostearic acid. It belongs to the PEG ester family and is designed to stabilize oil-in-water emulsions.
How it works
Its large molecular structure allows it to surround oil droplets and suspend them in water, preventing separation. It also increases the viscosity of the water phase, giving products a richer, more luxurious feel.
Pros
Excellent emulsion stability
Prevents oil and water from separating, so your product stays consistent from first use to last.
Low irritation potential
Generally well-tolerated on skin, even for sensitive types, because it stays on the surface and doesn't penetrate deeply.
Cons and cautions
Synthetic origin
Made from petroleum-derived materials, which may not align with a 'clean beauty' or natural skincare philosophy.
Potential processing impurities
If not highly purified, PEG compounds can contain trace levels of ethylene oxide or 1,4-dioxane, though reputable manufacturers use strict purification steps.
Best for
- Anyone using conventional moisturizers, cleansers, or sunscreens
- People who prefer stable, non-separating formulas with a creamy feel
Use caution if
- Those specifically avoiding PEG compounds due to personal preference or ethical sourcing concerns
Usage tips
Safety summary
PEG-175 Diisostearate is considered safe for use in cosmetics at typical concentrations. The main safety concern is potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, but reputable suppliers use purification processes to keep these impurities below trace levels. It has low irritation and comedogenic risk.
Research notes
The Cosmetic Ingredient Review (CIR) panel has evaluated PEG compounds and concluded they are safe for use in cosmetics when formulated to meet purity standards. No specific studies on PEG-175 Diisostearate were found, but its safety profile is consistent with other high-molecular-weight PEG esters.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission. The Cosmetic Ingredient Review (CIR) panel has reviewed PEG compounds and found them safe as used in cosmetics when properly purified.
- Common uses
- Moisturizers, Cleansers, Sunscreens, Makeup removers, Hair conditioners
- Environmental note
- As a synthetic polymer, it is not biodegradable. However, its large molecular size means it does not readily penetrate skin or aquatic organisms.
Good to know
- The number '175' refers to the average number of ethylene glycol units in the polymer chain, which affects its water solubility and thickening ability.
- PEG-175 Diisostearate is considered non-ionic, meaning it works well across a wide pH range.
Common questions
What is PEG-175 Diisostearate in beauty products?
PEG-175 Diisostearate is a man-made ingredient that helps oil and water mix together in a product so it stays smooth and doesn't separate. It also makes lotions feel thicker and creamier. The 'PEG' part means it's made with polyethylene glycol, a common emulsifier family in cosmetics.
What does PEG-175 Diisostearate do in a beauty product?
Its large molecular structure allows it to surround oil droplets and suspend them in water, preventing separation. It also increases the viscosity of the water phase, giving products a richer, more luxurious feel.
Is PEG-175 Diisostearate safe for most people?
PEG-175 Diisostearate is considered safe for use in cosmetics at typical concentrations. The main safety concern is potential contamination with ethylene oxide or 1,4-dioxane during manufacturing, but reputable suppliers use purification processes to keep these impurities below trace levels. It has low irritation and comedogenic risk.
Who should be careful with PEG-175 Diisostearate?
Those specifically avoiding PEG compounds due to personal preference or ethical sourcing concerns
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.