Ingredient review
PEG-33 Castor Oil
INCI: PEG-33 Castor Oil
A gentle, water-soluble emulsifier that helps mix oils into water-based formulas without clogging pores.
In plain English
PEG-33 Castor Oil is a modified version of castor oil that has been treated with polyethylene glycol (PEG) to make it dissolve in water. In skincare, it acts like a bridge between oil and water, allowing them to blend smoothly. This makes it useful in cleansers, makeup removers, and lotions where you want a lightweight, non-greasy feel. It is generally considered safe and non-irritating for most skin types.
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-33 Castor Oil 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-33 Castor Oil.
- 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-33 Castor Oil is a semi-synthetic ingredient created by reacting castor oil with 33 units of ethylene oxide (PEG). This process makes the naturally oil-soluble castor oil water-soluble, turning it into a versatile emulsifier and surfactant.
How it works
In a cosmetic formula, PEG-33 Castor Oil reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. It also helps dissolve fragrances and essential oils into water-based products, and can gently lift dirt and oil from the skin during cleansing.
Pros
Gentle on skin
PEG-33 Castor Oil has a low irritation and comedogenic risk, making it suitable for most skin types, including sensitive and acne-prone skin.
Versatile emulsifier
It effectively blends oils into water-based formulas, improving product texture and stability without leaving a greasy residue.
Cons and cautions
Potential trace impurity
During manufacturing, PEG compounds can contain trace amounts of 1,4-dioxane, a potential carcinogen. However, reputable brands purify their ingredients to meet safety limits.
Not natural
Although derived from castor oil, the PEG modification makes it semi-synthetic, which may not appeal to those seeking fully natural or organic products.
Best for
- People with normal to oily skin looking for a lightweight cleanser or makeup remover
- Anyone using water-based products that need to incorporate oils or fragrances
Use caution if
- Individuals with known sensitivity to PEG compounds or ethylene oxide derivatives
Usage tips
Safety summary
PEG-33 Castor Oil is considered safe for cosmetic use at typical concentrations. The main concern is trace contamination with 1,4-dioxane, but regulatory limits and purification processes keep levels well below safety thresholds. It is non-irritating and non-comedogenic for most users.
Research notes
Research supports the safety of PEG compounds in cosmetics when properly purified. The Cosmetic Ingredient Review (CIR) panel has reviewed PEG derivatives and found them safe for use in rinse-off and leave-on products at concentrations up to 25%. No significant skin sensitization or toxicity has been reported in standard tests.
Common label clues
- Typical concentration
- 1–10% in rinse-off products; lower in leave-on products
- Regulatory status
- Approved for use in cosmetics by the FDA and the European Commission, with concentration limits for leave-on products to minimize potential irritation.
- Common uses
- Cleansers, Makeup removers, Fragrance solubilizer, Lotions, Creams
- Environmental note
- PEG compounds are not readily biodegradable, but they are used in low concentrations and are generally considered safe for the environment when disposed of properly.
Good to know
- PEG-33 Castor Oil is often used to solubilize fragrances and essential oils in water-based products like toners and mists.
- The number '33' refers to the average number of ethylene oxide units, which determines its water solubility and mildness.
Common questions
What is PEG-33 Castor Oil in beauty products?
PEG-33 Castor Oil is a modified version of castor oil that has been treated with polyethylene glycol (PEG) to make it dissolve in water. In skincare, it acts like a bridge between oil and water, allowing them to blend smoothly. This makes it useful in cleansers, makeup removers, and lotions where you want a lightweight, non-greasy feel. It is generally considered safe and non-irritating for most skin types.
What does PEG-33 Castor Oil do in a beauty product?
In a cosmetic formula, PEG-33 Castor Oil reduces the surface tension between oil and water, allowing them to mix into a stable emulsion. It also helps dissolve fragrances and essential oils into water-based products, and can gently lift dirt and oil from the skin during cleansing.
Is PEG-33 Castor Oil safe for most people?
PEG-33 Castor Oil is considered safe for cosmetic use at typical concentrations. The main concern is trace contamination with 1,4-dioxane, but regulatory limits and purification processes keep levels well below safety thresholds. It is non-irritating and non-comedogenic for most users.
Who should be careful with PEG-33 Castor Oil?
Individuals with known sensitivity to PEG compounds or ethylene oxide derivatives
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.