Peg-30 Phytosterol: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: July 1, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Peg-30 Phytosterol?

Peg-30 Phytosterol is a plant-derived ingredient created by attaching roughly 30 units of ethylene oxide to natural phytosterols, the cholesterol-like compounds found in soybeans, vegetable oils and other plant fats. This ethoxylation step gives the molecule a water-loving “PEG” side and an oil-loving phytosterol side, turning it into an effective bridge between oil and water. First explored in the late 20th century as formulators searched for milder alternatives to animal-based emulsifiers, it quickly earned a spot in skin care because it could stabilize creams without a heavy or greasy feel.

Production begins with purified plant sterols that are reacted with ethylene oxide under controlled temperature and pressure. The result is a uniform powder or waxy solid that disperses easily once heated into the oil phase of a formulation. Thanks to its dual nature, Peg-30 Phytosterol shows up in moisturizers, sunscreens, leave-on conditioners, facial masks, lightweight lotions, anti-aging serums and even some color cosmetics where a smooth, consistent texture is critical.

Peg-30 Phytosterol’s Cosmetic Benefits/Uses

In skin and hair care formulas Peg-30 Phytosterol is valued for one key role.

Emulsifying: By positioning its water-friendly PEG chain in the aqueous phase and its phytosterol tail in the oil phase, Peg-30 Phytosterol keeps immiscible ingredients blended into a stable, uniform mixture. This prevents separation over time, improves the spreadability of creams and lotions, ensures an even dose of active ingredients with each use and contributes to a lighter, non-greasy skin feel.

Who Can Use Peg-30 Phytosterol

Peg-30 Phytosterol is generally well tolerated by all major skin types including dry, oily and combination because it is used at low concentrations and has a lightweight finish. Sensitive skin usually handles it well too since phytosterols are naturally soothing, though people with a known allergy to soy or other plant sterols may want to take extra caution.

The ingredient is plant derived and processed without animal inputs so it fits within vegan and vegetarian lifestyles. Its use in place of animal sourced emulsifiers is one reason many cruelty-free brands choose it.

No data suggest Peg-30 Phytosterol poses a specific risk to pregnant or breastfeeding women when applied topically. Still, this is not medical advice and anyone who is expecting or nursing should review their skincare routine with a qualified healthcare professional to be safe.

The molecule does not increase photosensitivity and there are no special sun-exposure warnings tied to it. It is also fragrance free and non volatile so it will not interfere with essential oils, acids or most other common actives in a formula.

Potential Side Effects/Adverse Reactions

Side effects from topical Peg-30 Phytosterol vary from person to person. The following issues are possible yet uncommon when the ingredient is used at normal cosmetic levels:

  • Redness or mild irritation
  • Itchiness in people with plant sterol allergies
  • Watery eyes if the product accidentally reaches the eye area
  • Contact dermatitis in extremely sensitive individuals

If any of these reactions occur stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 1 out of 5

Peg-30 Phytosterol sits close to the water phase of a formula thanks to its long PEG chain so it rinses or wears off easily instead of clogging pores. The phytosterol part is plant based and lightweight, not a heavy wax. Together this keeps the molecule from building up inside follicles which is why most formulators rate it a 1.

That low score means Peg-30 Phytosterol is generally suitable for acne-prone or breakout-prone skin.

Its final comedogenic impact also depends on the other oils and butters in the finished product as well as how thoroughly the user cleanses at the end of the day.

Summary

Peg-30 Phytosterol is a plant derived emulsifier that lines up its water loving PEG side with the water in a formula and its oil loving sterol side with the oils. By doing so it locks the two together, giving creams and lotions a smooth feel, an even look and a stable shelf life. It does all this without adding weight or greasiness.

The ingredient is not a big name on its own but it quietly powers many modern moisturizers, sunscreens and lightweight serums that market themselves as vegan or cruelty free.

Safety data show a low risk of irritation, allergy or clogged pores when used at normal cosmetic levels. Even so everyone’s skin is different so it is always smart to patch test a new product that contains Peg-30 Phytosterol before fully adding it to your routine.

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