What Is Peg-10 Hydrogenated Castor Oil Isostearate?
Peg-10 Hydrogenated Castor Oil Isostearate is a plant-derived ingredient that starts with castor oil pressed from the seeds of the Ricinus communis plant. The oil is first hydrogenated to turn its liquid fatty acids into more stable saturated ones, then reacted with roughly ten units of ethylene oxide to make it water compatible. Finally, it is esterified with isostearic acid, a branched fatty acid that boosts spreadability and softness. The result is a waxy, semi-solid substance that works well in both water and oil phases.
Castor derivatives have been used as surfactants since the mid-1900s when formulators searched for gentle plant alternatives to soap. Adding polyethylene glycol (PEG) chains and isostearate groups gave the material stronger emulsifying power and a smoother skin feel, so it quickly found a place in modern skin and hair care labs.
Production involves three main steps: hydrogenating raw castor oil under high pressure to saturate the double bonds, ethoxylating the hydrogenated oil with controlled amounts of ethylene oxide, then reacting the intermediate with isostearic acid to form the final monoester. Strict purification removes traces of free EO and by-products, leaving a cosmetic-grade ingredient that meets global safety standards.
You will most often see Peg-10 Hydrogenated Castor Oil Isostearate in moisturizers, lotions, face masks, anti-aging serums, makeup removers, sunscreens, creamy cleansers, hair conditioners and styling creams where a stable oil-in-water emulsion and a smooth glide are needed.
Peg-10 Hydrogenated Castor Oil Isostearate’s Cosmetic Benefits/Uses
Formulators reach for this multitasker because it improves both texture and performance in a wide variety of products.
- Emulsifying – helps water and oil blend into a uniform cream or lotion, preventing separation and ensuring each application delivers active ingredients evenly
- Viscosity controlling – fine-tunes thickness so a formula feels rich yet spreads easily without dripping or feeling greasy
Who Can Use Peg-10 Hydrogenated Castor Oil Isostearate
This ingredient is generally considered suitable for all skin types including dry, normal, combination, oily and sensitive skin because it is lightweight and non occlusive while still providing a smooth glide. Extremely acne prone users who react to most fatty alcohols or castor derivatives may want to keep an eye on how their skin responds.
Peg-10 Hydrogenated Castor Oil Isostearate is produced from plant sources and synthetic processing steps so it is appropriate for both vegans and vegetarians with no animal derived components involved.
Current safety assessments show no specific hazards for pregnant or breastfeeding women when the ingredient is used at typical cosmetic levels. This is not medical advice and anyone who is expecting or nursing should have a doctor review any skincare product they plan to use just to be safe.
The ingredient does not make skin more sensitive to sunlight and there are no known interactions with UV exposure.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-10 Hydrogenated Castor Oil Isostearate can differ from person to person. The following are potential side effects that are uncommon when the ingredient is used correctly in finished cosmetics
- Mild skin irritation such as redness or stinging in very sensitive individuals
- Allergic contact dermatitis in people with a castor oil allergy
- Temporary clogged pores or small breakouts in users who are highly acne prone
- Eye irritation if a product accidentally gets into the eyes
If any of these reactions occur stop using the product and consult a qualified healthcare professional
Comedogenic Rating
Rating: 1/5. The molecule is highly ethoxylated which makes it water compatible, helps it rinse off easily and limits the heavy oily feel linked to clogged pores. Its branched isostearate tail spreads thinly rather than forming a thick film, so it is far less occlusive than raw castor oil. Most formulators consider it low risk for breakouts which is why it is found in many lightweight lotions, gels and even some acne care products.
Overall it is usually suitable for skin that is prone to acne though extremely reactive users may still want to monitor how their skin responds.
Formulation level, presence of other acne triggers and personal skin chemistry all influence real-world comedogenicity so the full product formula matters as much as the rating of any single ingredient.
Summary
Peg-10 Hydrogenated Castor Oil Isostearate is mainly an emulsifier and viscosity controller. Its water-loving PEG chains grab onto the aqueous phase while its fatty isostearate segment anchors into oils, letting it pull the two phases together into a stable cream or lotion. The hydrogenated backbone offers oxidative stability that keeps products smooth and fresh, and the branched structure tweaks thickness so formulas feel silky not greasy.
It is a quiet workhorse found in a fair number of moisturizers, sunscreens and makeup removers but it rarely gets called out on the front label, so casual shoppers might not realize how often they use it.
Current safety reviews find it to be low risk for irritation or sensitization at typical use levels, and regulatory bodies allow it worldwide. As always, anyone trying a new product should do a quick patch test first to confirm personal compatibility.