What Is Peg-58 Hydrogenated Castor Oil Isostearate?
Peg-58 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, a process that adds hydrogen to make it more solid and stable. Next the hydrogenated oil is reacted with ethylene oxide, attaching an average of 58 ethoxy units that help it blend with water. Finally it is combined with isostearic acid to form an ester, giving the finished material a soft feel and extra compatibility with skin care oils.
The cosmetic industry began exploring modified castor oil in the mid 20th century when formulators needed gentler alternatives to animal based waxes and soaps. By tailoring the oil with hydrogenation, ethoxylation and esterification, chemists created a versatile ingredient that could stabilize modern emulsions without a heavy or greasy residue. Today Peg-58 Hydrogenated Castor Oil Isostearate appears in a wide range of leave on and rinse off products including facial moisturizers, body lotions, sunscreens, makeup removers, sheet masks, hair conditioners and creamy cleansers.
Commercial production typically takes place in three steps. First food grade castor oil is hydrogenated in the presence of a nickel catalyst. The hardened wax is then fed into reactors where controlled amounts of ethylene oxide are added under pressure to reach around 58 moles of ethoxylation. Finally the ethoxylated wax is esterified with isostearic acid, purified and milled into an easy to handle pastille or liquid for cosmetic labs.
Peg-58 Hydrogenated Castor Oil Isostearate’s Cosmetic Benefits/Uses
This multi tasking ingredient supports both the texture and stability of personal care formulas.
- Emulsifying: Helps oil and water stay mixed, preventing creams and lotions from separating so the product remains smooth and effective throughout its shelf life
- Viscosity controlling: Adjusts thickness, giving light lotions a silky glide or rich creams a cushiony feel while still spreading easily on skin or hair
Who Can Use Peg-58 Hydrogenated Castor Oil Isostearate
This ingredient is considered gentle enough for most skin types including normal, dry, combination and oily skin. Its lightweight, non greasy finish makes it suitable even for acne-prone users who prefer formulas that do not feel heavy. Those with very sensitive or highly reactive skin should still check the full ingredient list of a product since other components, not this emulsifier itself, could pose an issue.
Peg-58 Hydrogenated Castor Oil Isostearate is made from plant derived castor oil and synthetic processing aids so it fits vegan and vegetarian preferences. No animal sourced materials are used during its manufacture.
Current safety data show no specific reproductive or developmental risks, meaning products containing this emulsifier are generally viewed as safe for people who are pregnant or breastfeeding. This is not medical advice and anyone who is expecting or nursing should have a doctor review their skincare routine to be sure every product aligns with their personal health plan.
The ingredient does not absorb UV light and is not known to cause photosensitivity, so it will not make skin more prone to sunburn. It also does not interfere with typical actives such as retinoids or exfoliating acids, allowing it to sit comfortably in most routines.
Potential Side Effects/Adverse Reactions
Responses to topical Peg-58 Hydrogenated Castor Oil Isostearate can differ from one person to another. The following points list potential but uncommon side effects. When formulated correctly most users will not notice any of these issues.
- Mild skin irritation
- Redness or itching linked to a personal sensitivity to castor oil derivatives or PEG compounds
- Contact dermatitis in individuals with a documented allergy to ricinoleic derivatives
- Transient eye stinging if a product containing the ingredient is accidentally rubbed into the eyes
- Breakouts in users who are already very prone to clogged pores when rich creams are applied too thickly
If any adverse reaction develops stop using the product and seek guidance from a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Peg-58 Hydrogenated Castor Oil Isostearate carries a very low risk of clogging pores because its long PEG chain makes it highly water compatible, so it tends to rinse or wear off without leaving a thick oily film. The hydrogenation step removes the naturally sticky ricinoleic acids found in raw castor oil, further cutting down the chance of buildup that might trap dead cells or sebum. Laboratory tests and user reports rarely link this emulsifier to persistent blackheads or whiteheads.
Suitable for acne-prone skin in most formulas.
Keep in mind that the overall comedogenicity of a finished product depends on the full recipe. A cream packed with heavy plant butters could still feel greasy even if this emulsifier scores low on its own.
Summary
Peg-58 Hydrogenated Castor Oil Isostearate stabilises oil and water blends and fine-tunes thickness so lotions glide easily yet stay put. It does this by surrounding tiny oil droplets with its PEG side that loves water and its fatty side that loves oil, creating a stable emulsion, while the waxy backbone adds body without heaviness.
The ingredient is popular with formulators because it is reliable, plant based and cost effective, but it rarely gets spotlighted on product labels so most shoppers are unaware of its role.
Current safety reviews find it non irritating for the majority of users with no evidence of long-term health risks. Still, skin can be unpredictable so it is wise to patch test any new product that contains this or any other unfamiliar ingredient.