What Is Peg-100 Castor Oil?
PEG-100 Castor Oil is a modified form of traditional castor oil, which comes from the seeds of the castor bean plant Ricinus communis. Through a process called ethoxylation, roughly 100 units of ethylene oxide are added to the natural oil, turning the thick sticky liquid into a lighter water-compatible ingredient. This tweak lets the oil blend smoothly with both water-based and oil-based substances, something raw castor oil cannot do on its own.
Castor oil itself has been used for generations in folk beauty practices, but the ethoxylated version started gaining popularity in the mid-20th century when chemists looked for milder alternatives to harsh soaps. By adding the polyethylene glycol (PEG) chains, they created a gentle surfactant that could lift away dirt without stripping skin. Today manufacturers often choose PEG-100 Castor Oil because it is plant-derived, versatile and relatively inexpensive.
The ingredient is produced in controlled reactors where purified castor oil is combined with ethylene oxide under heat and pressure. Afterward the mixture is cleaned and tested to ensure consistent quality before it heads to formulation labs.
You will spot PEG-100 Castor Oil in a wide variety of products: facial cleansers, rinse-off masks, micellar waters, makeup removers, body washes, creamy moisturizers and even some leave-on hair conditioners where it helps keep oils and water in a stable, silky mix.
Peg-100 Castor Oil’s Cosmetic Benefits/Uses
Below are the main ways this multitasker improves a formula
- Cleansing: Acts as a gentle surfactant that loosens makeup, sunscreen and everyday grime so they rinse away easily. Because it is milder than many traditional detergents, it helps maintain the skin’s natural moisture barrier and leaves a soft feel after washing.
- Emulsifying: Keeps oil and water phases blended into a smooth, uniform product. This stability prevents separation in creams, lotions and cleansers, giving users a consistent texture and ensuring each squeeze or pump delivers the same balance of ingredients.
Who Can Use Peg-100 Castor Oil
Thanks to its mild cleansing nature Peg-100 Castor Oil is generally well tolerated by most skin types, including dry, normal, combination and oily. Sensitive skin usually handles it without trouble since the ingredient is less stripping than many sulfate based surfactants. Those with very acne prone skin may want to monitor how their complexion responds because any emulsifier can theoretically trap debris if a formula is not rinsed thoroughly, though the risk is low.
The ingredient is sourced from castor beans so it is suitable for vegans and vegetarians. No animal derived compounds are used in its manufacture, nor is animal testing required for the ingredient itself in most regions.
Current safety data shows no specific concerns for pregnant or breastfeeding women when the ingredient is used in rinse off or leave on cosmetics at normal levels. That said this is not medical advice and anyone who is pregnant or nursing should review their skincare lineup with a qualified healthcare professional to be cautious.
Peg-100 Castor Oil does not make skin more sensitive to sunlight and there is no evidence it affects self tanning or UV protection claims in sunscreen formulas.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-100 Castor Oil differ from person to person. The points below outline possible reactions though most users will experience none of them when the ingredient is correctly formulated into a product.
- Mild skin irritation in individuals with highly reactive skin, often presenting as temporary redness or itching
- Allergic contact dermatitis in rare cases for those specifically allergic to castor derivatives or polyethylene glycols
- Eye stinging or watering if a cleanser containing the ingredient is not fully rinsed away
- Excessive dryness when used in very high concentrations or in formulas lacking complementary moisturizers
- Residual 1,4-dioxane traces if the manufacturer has not adequately removed processing byproducts, a quality control rather than user sensitivity issue
If you experience any discomfort swelling or persistent irritation discontinue use immediately and seek advice from a medical professional or dermatologist.
Comedogenic Rating
Rating: 1 out of 5. Peg-100 Castor Oil starts with a low-comedo raw material (castor oil usually scores 1) and then is heavily modified into a water-soluble surfactant. Because it readily rinses away and does not leave an occlusive film, its tendency to clog pores is minimal. Most formulators use it at modest levels, further reducing any buildup risk.
Overall this ingredient is generally considered suitable for people who break out easily, provided the finished product is well balanced and properly rinsed.
Keep in mind that very rich creams containing high percentages of multiple emulsifiers or oils may still feel heavy on some complexions, so the full formula matters more than any single component.
Summary
Peg-100 Castor Oil acts mainly as a gentle cleanser and a dependable emulsifier. Its PEG chains attract water while the castor oil backbone grabs onto oils, letting it lift dirt then mix everything into a stable solution that washes off cleanly.
The ingredient is a quiet workhorse rather than a headline star. It shows up in countless face washes, micellar waters and lotions because it is plant derived, budget friendly and easy to incorporate, though most shoppers never notice its name on the label.
Current research and long-standing use point to a strong safety profile when manufactured to quality standards. It rarely triggers irritation and does not interfere with sun exposure or common actives. As with any new skincare product, a quick patch test is a smart step before full use just to confirm personal compatibility.