Ingredient review
PEG-9 Stearamide Carboxylic Acid
INCI: PEG-9 Stearamide Carboxylic Acid
A gentle, PEG-based surfactant that helps cleanse without stripping the skin's natural moisture barrier.
In plain English
PEG-9 Stearamide Carboxylic Acid is a mild cleansing ingredient often used in facial cleansers and body washes. It helps remove dirt and oil while being less harsh than traditional soaps. The 'PEG' part means it's made with polyethylene glycol, which makes it water-friendly and gentle on 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
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
PEG-9 Stearamide Carboxylic Acid 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-9 Stearamide Carboxylic Acid.
- 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 semi-synthetic surfactant created by reacting stearic acid (a fatty acid from plant or animal sources) with polyethylene glycol and an amide group. It belongs to the class of PEG carboxylates, known for their mildness.
How it works
It works by reducing the surface tension between water and oil, allowing dirt and excess sebum to be rinsed away. Its carboxylate group gives it a gentle cleansing action that is less likely to disrupt the skin's natural barrier compared to stronger sulfates.
Pros
Very gentle on skin
Unlike harsh sulfates, this surfactant cleans without stripping natural oils, making it ideal for daily use on sensitive or dry skin.
Good foam and rinse feel
It produces a moderate lather that rinses cleanly, leaving skin feeling soft rather than tight or squeaky.
Cons and cautions
PEG-related purity concerns
PEG compounds can sometimes contain trace impurities like ethylene oxide or 1,4-dioxane if not properly purified, though reputable brands use high-quality grades.
Not fully natural
As a semi-synthetic ingredient, it may not appeal to consumers seeking 100% natural or organic formulations.
Best for
- People with dry or sensitive skin looking for a mild cleanser
- Those who prefer sulfate-free cleansing options
Use caution if
- Individuals with known allergies to PEG derivatives (rare)
- Those seeking fully natural or plant-based ingredients
Usage tips
Safety summary
Generally recognized as safe for topical use in rinse-off cosmetics at typical concentrations. The main concern is potential trace impurities from PEG manufacturing, which are well-controlled in quality products.
Research notes
Limited peer-reviewed studies specifically on PEG-9 Stearamide Carboxylic Acid, but the broader class of PEG carboxylates is well-documented as mild surfactants with low irritation potential. Safety assessments by the Cosmetic Ingredient Review (CIR) support their use.
Common label clues
- Typical concentration
- 1–10% in rinse-off products
- Regulatory status
- Approved for use in cosmetics by the FDA and EU CosIng database. Manufacturers should ensure low levels of impurities per ICH guidelines.
- Common uses
- Cleansers, Facial washes, Shampoos, Body washes
- Environmental note
- PEG-based surfactants can be slow to biodegrade in aquatic environments. Some brands are moving toward more biodegradable alternatives.
Good to know
- PEG-9 Stearamide Carboxylic Acid is often listed near the middle of an ingredient list, indicating moderate concentration.
- It is compatible with a wide pH range, making it versatile in different product types.
Common questions
What is PEG-9 Stearamide Carboxylic Acid in beauty products?
PEG-9 Stearamide Carboxylic Acid is a mild cleansing ingredient often used in facial cleansers and body washes. It helps remove dirt and oil while being less harsh than traditional soaps. The 'PEG' part means it's made with polyethylene glycol, which makes it water-friendly and gentle on skin.
What does PEG-9 Stearamide Carboxylic Acid do in a beauty product?
It works by reducing the surface tension between water and oil, allowing dirt and excess sebum to be rinsed away. Its carboxylate group gives it a gentle cleansing action that is less likely to disrupt the skin's natural barrier compared to stronger sulfates.
Is PEG-9 Stearamide Carboxylic Acid safe for most people?
Generally recognized as safe for topical use in rinse-off cosmetics at typical concentrations. The main concern is potential trace impurities from PEG manufacturing, which are well-controlled in quality products.
Who should be careful with PEG-9 Stearamide Carboxylic Acid?
Individuals with known allergies to PEG derivatives (rare) Those seeking fully natural or plant-based 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.