What Is Peg-36 Castor Oil?
PEG-36 castor oil is castor oil that has been linked to about 36 units of ethylene oxide, turning the thick natural oil into a water-friendly liquid. Castor beans supply the base oil, which is mostly ricinoleic acid, a fatty acid valued for its smooth feel. By adding ethylene oxide, chemists created a plant-based surfactant that could replace animal fats and mineral oils, a shift that took hold in the mid-20th century when demand for gentler cleansers grew.
Manufacturers make it through ethoxylation: castor oil is warmed then reacted with ethylene oxide under controlled pressure. The “36” shows the average number of ethylene oxide units attached to each castor oil molecule, a figure that decides how easily the ingredient dissolves in water.
You will find PEG-36 castor oil in facial cleansers, micellar waters, shampoos, bath gels, baby wipes, makeup removers, moisturizing lotions, light creams and sheet mask essences. Any product that must lift away dirt or makeup while still feeling silky can benefit from it.
Peg-36 Castor Oil’s Cosmetic Benefits/Uses
The ingredient earns its spot in formulas through the functions below
- Cleansing: Works as a mild surfactant that loosens dirt, sunscreen and makeup so they rinse away with water leaving skin or hair fresh yet comfortable
- Emulsifying: Keeps oil and water parts of a product blended giving lotions and washes a smooth stable texture and preventing separation on the shelf
Who Can Use Peg-36 Castor Oil
Because it is a gentle, water-soluble form of castor oil, PEG-36 castor oil suits most skin types including oily, combination, dry and mature skin. Those with very reactive or eczema-prone skin may want to watch for any personal sensitivity to polyethylene glycol ingredients, as they can occasionally trigger redness or itching in highly delicate complexions.
The ingredient is produced from castor beans and synthetic ethylene oxide, so no animal-derived substances are involved. That makes it acceptable for vegans and vegetarians.
Current safety data indicate no known reproductive hazards, so products containing PEG-36 castor oil are generally considered safe for pregnant or breastfeeding women. This is not medical advice and anyone who is pregnant or nursing should ask a doctor before adding new skincare just to be sure.
PEG-36 castor oil does not absorb UV light and is not known to cause photosensitivity. It also has no fragrance of its own, which reduces the chance of scent-related irritation.
Potential Side Effects/Adverse Reactions
Reactions to topical PEG-36 castor oil differ from one person to another. The issues listed below are possible yet uncommon, and most users will not experience them when the ingredient is formulated and used correctly.
- Irritation or stinging in very sensitive skin, especially on broken or compromised barriers
- Allergic contact dermatitis presenting as redness, itching or small bumps in those allergic to castor oil or PEGs
- Eye discomfort such as watering or mild stinging if a cleanser or makeup remover is not rinsed away fully
- Dryness if a high-foam formula containing the ingredient is overused on already dry skin
- Contamination risk with trace 1,4-dioxane if manufacturing purification steps are skipped, though reputable brands routinely remove it
If any irritation or adverse effect occurs stop using the product and seek advice from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1/5
PEG–36 castor oil is highly water soluble thanks to its long PEG chain so it rinses clean instead of sitting on the skin and clogging pores. The base fatty acid, ricinoleic acid, already scores low for pore blockage and ethoxylation lowers the risk even further. Most formulas also use it at modest levels, often in products that wash off, which keeps the comedogenic potential minimal.
Suitable for acne-prone or breakout-prone skin in both leave-on and rinse-off formats, though individual responses can differ.
Because the ingredient is usually combined with other surfactants and emollients, the overall pore-clogging risk depends on the full formula, not just this single component.
Summary
PEG-36 castor oil serves mainly as a mild cleanser and an emulsifier. Its castor oil portion loves oils while its PEG portion loves water, letting it surround dirt, makeup and sebum so they lift away easily and keeping oil and water in a lotion mixed without separating. This dual nature gives products a silky feel and reliable stability.
Though not a headline ingredient, it is a quiet workhorse found in many everyday cleansers, micellar waters, shampoos and light creams. Formulators like it because it is plant based, versatile and gentle.
Safety reviews rate it low risk when properly purified to remove trace 1,4-dioxane. Most people tolerate it well, including pregnant users and vegans, but as with any new skincare step perform a patch test first to be sure your skin is happy.