What Is Peg-40 Hydrogenated Castor Oil Triisostearate?
Peg-40 Hydrogenated Castor Oil Triisostearate starts out as castor oil pressed from the seeds of the Ricinus communis plant. Chemists first fully saturate the oil with hydrogen, which turns the naturally fluid oil into a waxy solid that resists oxidation. They then attach roughly forty units of ethylene oxide to the molecule, giving it the PEG, or polyethylene glycol, part of its name. A final step links the modified castor oil to isostearic acid, a branched fatty acid that improves flow and feel. The finished ingredient is a hybrid of oil and water-loving parts, so it acts like a bridge between the two.
Castor oil has been a beauty staple since the early 1900s thanks to its thick, cushioning texture. As formulas moved from simple cold creams to today’s light lotions and gels, chemists needed castor derivatives that could mix smoothly with water. Peg-40 Hydrogenated Castor Oil Triisostearate emerged in the 1980s as one of those solutions and has stayed popular because it is reliable, mild and versatile.
You will most often spot this ingredient in facial cleansers, micellar waters, makeup removers, moisturizers, sunscreens, sheet masks, hair conditioners and styling creams. Anywhere a formulator wants oil, water and active ingredients to stay blended, this multifunctional castor oil derivative is a go-to.
Peg-40 Hydrogenated Castor Oil Triisostearate’s Cosmetic Benefits/Uses
Here is how its key roles improve a wide range of beauty products:
- Emulsifying: It keeps oily and watery ingredients mixed into a stable, even solution so the product looks uniform, feels pleasant and delivers active ingredients evenly with every use
- Viscosity Controlling: It fine-tunes thickness, giving light cleansers a bit more body or helping rich creams glide on without feeling greasy
Who Can Use Peg-40 Hydrogenated Castor Oil Triisostearate
This ingredient is generally considered suitable for all skin types including dry, normal, combination and oily skin because it is non-greasy, lightweight and helps balance water and oil in a formula. Sensitive skin usually tolerates it well thanks to its mild nature, though anyone with a known allergy to castor derivatives should proceed cautiously.
The raw materials are plant based and no animal-derived substances are used during production, so the ingredient is appropriate for vegans and vegetarians.
Current safety data indicate no specific risks for pregnant or breastfeeding women, but this is not medical advice. Anyone expecting or nursing should show the full product ingredient list to a healthcare professional before adding a new cosmetic to their routine to be extra safe.
Peg-40 Hydrogenated Castor Oil Triisostearate does not increase skin’s sensitivity to sunlight, so it will not make you more prone to sunburn. It is also odorless and free of essential oil allergens, making it a low-risk choice for fragrance-avoidant users.
Potential Side Effects/Adverse Reactions
Individual responses to topical Peg-40 Hydrogenated Castor Oil Triisostearate vary. The points below outline potential, but unlikely, reactions when the ingredient is used at the levels commonly found in finished cosmetics. When manufactured and preserved correctly most people experience no negative effects.
- Mild skin irritation
- Temporary eye stinging if a cleanser or makeup remover is rinsed poorly
- Allergic contact dermatitis in people sensitive to castor oil or polyethylene glycol compounds
- Breakouts in acne-prone skin if used in very heavy leave-on formulas
If you experience redness, itching or any discomfort stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Peg-40 Hydrogenated Castor Oil Triisostearate is heavily modified from natural castor oil, and the hydrogenation plus PEG-ylation make the molecule more water compatible and less likely to build up inside pores. Laboratory data and user reports show a very low tendency to trigger comedones. Occasional breakouts can occur if the finished formula is thick and left on skin, but the ingredient itself is considered a minimal clogging risk. Acne-prone users can usually use products containing it without problems.
If the product pairs this emulsifier with heavy waxes or butters the overall formula could still feel occlusive, so always assess the whole ingredient list.
Summary
Peg-40 Hydrogenated Castor Oil Triisostearate acts as an emulsifier and viscosity controller, letting oil and water sit happily together while tweaking thickness for a smoother feel. Its hybrid structure—part oil, part water-loving PEG—creates stable, elegant textures in cleansers, creams, micellar waters and hair products.
It enjoys steady popularity because it is plant derived, versatile and mild, though it is not as buzzworthy as newer sugar or amino acid based emulsifiers.
Current safety reviews find it low risk for irritation, sensitization or pore clogging when used at normal cosmetic levels. As with any new cosmetic, patch test first to make sure your skin agrees.