Ingredient review

PEG-35 Hydrogenated Castor Oil

INCI: PEG-35 HYDROGENATED CASTOR OIL

A well-tolerated emulsifier that helps mix oil and water in your products, but may feel heavy on very oily skin.

beautyskincareemulsifier

In plain English

PEG-35 Hydrogenated Castor Oil is a modified version of castor oil that has been treated with ethylene oxide (PEG) and hydrogenated to make it more stable and water-friendly. In skincare, it acts as a bridge between oil and water, allowing them to blend into a smooth cream or lotion. It also helps dissolve makeup and sunscreen so they rinse off easily. Because it's derived from castor oil, it has a mild, non-drying feel, but the PEG modification means it can sometimes leave a slight residue on very oily skin.

Review score

Safety, usefulness, and evidence

4.0Good

4.0/ 5

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

How reviews are scored

Quick decision guide

Useful, but context matters

PEG-35 Hydrogenated 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-35 Hydrogenated 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

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

A semi-synthetic emulsifier made by reacting hydrogenated castor oil with polyethylene glycol (PEG). It is a waxy, water-soluble ingredient that helps stabilize oil-in-water emulsions.

How it works

Its molecular structure has both water-loving (PEG chain) and oil-loving (castor oil) parts. When added to a formula, it positions itself at the interface of oil and water droplets, reducing surface tension so they stay mixed. This prevents separation and gives products a uniform, creamy texture.

Pros

Gentle emulsifier

It helps blend oil and water without harsh detergents, making it suitable for sensitive skin and daily cleansing.

Effective makeup remover

Its oil-loving part dissolves long-wear makeup and sunscreen, so you can remove them without rubbing or irritation.

Cons and cautions

Potential residue

On very oily skin, it can leave a slight film that may feel heavy or contribute to clogged pores if not fully rinsed.

PEG processing concerns

The PEG manufacturing process can introduce trace impurities like 1,4-dioxane, though high-quality cosmetic grades are purified to safe levels.

Best for

People with normal to dry skin who want a gentle, non-stripping cleanser or makeup remover
Anyone using oil-based serums or sunscreens who wants a stable, well-mixed formula

Use caution if

Those with very oily or acne-prone skin who prefer lightweight, residue-free textures

Usage tips

Use in a double-cleansing routine: apply an oil-based cleanser containing this ingredient first, then follow with a water-based cleanser to remove any residue.

If you have oily skin, look for formulas where this ingredient is listed lower on the ingredient list to minimize film feel.

Safety summary

PEG-35 Hydrogenated Castor Oil is considered safe for cosmetic use at typical concentrations. It has low irritation and comedogenic potential. The main safety concern is potential contamination with 1,4-dioxane during manufacturing, but reputable suppliers use purification steps to keep levels within safe limits.

Research notes

The Cosmetic Ingredient Review (CIR) panel has reviewed PEG derivatives and concluded they are safe for use in cosmetics when formulated to be non-irritating. Studies show PEG-35 Hydrogenated Castor Oil has low acute toxicity and is not a significant skin sensitizer.

Common label clues

Typical concentration: 1% to 10% in rinse-off products; lower in leave-on formulas
Regulatory status: Approved for use in cosmetics by the FDA and EU CosIng database. The Cosmetic Ingredient Review (CIR) panel has evaluated PEG derivatives and found them safe when formulated to minimize impurities.
Common uses: Cleansers, Makeup removers, Moisturizers, Sunscreens, Serums
Environmental note: Castor oil is a renewable plant-based resource. However, the PEG process uses ethylene oxide derived from fossil fuels, and the ingredient may not be fully biodegradable in aquatic environments.

Good to know

Hydrogenation makes castor oil more stable and less likely to go rancid, extending product shelf life.
PEG-35 refers to the average number of ethylene oxide units (35) attached to the castor oil molecule, which determines its water solubility.

Common questions

What is PEG-35 Hydrogenated Castor Oil in beauty products?

What does PEG-35 Hydrogenated Castor Oil do in a beauty product?

Is PEG-35 Hydrogenated Castor Oil safe for most people?

Who should be careful with PEG-35 Hydrogenated Castor Oil?

Those with very oily or acne-prone skin who prefer lightweight, residue-free textures

Research sources

Cosmetic Ingredient Review (CIR) – Safety Assessment of PEGsOpen EU CosIng Database – PEG-35 Hydrogenated Castor OilOpen PubMed – Safety of PEG derivatives in cosmeticsOpen

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.