Peg/Ppg-160/31 Copolymer: 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/Ppg-160/31 Copolymer?

Peg/Ppg-160/31 Copolymer is a synthetic ingredient created by reacting 160 units of ethylene oxide with 31 units of propylene oxide, forming a block copolymer that blends water-friendly and oil-friendly segments. This dual nature lets it mix substances that normally would not blend, which is why formulators value it.

The use of polyethylene glycol (PEG) and polypropylene glycol (PPG) materials in beauty products dates back to the late 1970s when chemists sought stable, easy-to-use solvents that would not irritate skin. By tweaking the ratio of ethylene oxide to propylene oxide they produced a range of copolymers with different textures and solubility profiles. Peg/Ppg-160/31 Copolymer emerged as a reliable choice for water-based lotions and creams because its high ethylene oxide content boosts water solubility while the propylene oxide portion keeps oily ingredients evenly dispersed.

Manufacturing starts with purified ethylene oxide and propylene oxide gases. Under controlled pressure and temperature they undergo sequential polymerization on a starter molecule, first adding propylene oxide units then ethylene oxide units. The resulting viscous liquid is purified, tested for residual monomers and standardized for cosmetic use.

You can find Peg/Ppg-160/31 Copolymer in lightweight moisturizers, hydrating serums, sheet mask essences, hair conditioners, leave-on styling creams, gentle cleansers and aftershave balms where it helps keep formulas clear and uniform.

Peg/Ppg-160/31 Copolymer’s Cosmetic Benefits/Uses

In skincare and hair care Peg/Ppg-160/31 Copolymer serves one key role.

As a solvent it dissolves active ingredients, fragrances and preservatives so they distribute evenly throughout a product. This improves texture, prevents separation and ensures that every pump or swipe delivers the same concentration of beneficial ingredients. A good solvent also helps a formula feel lighter on the skin because it avoids heavy oils that can leave residue, making products with this copolymer suitable for users who prefer a clean non-greasy finish.

Who Can Use Peg/Ppg-160/31 Copolymer

This solvent suits most skin types including normal, dry, oily and combination because it is lightweight, non-comedogenic and rinses away easily. Even sensitive skin generally tolerates it since it has a low irritation profile, though people with a known sensitivity to polyethylene glycol or polypropylene glycol derivatives may prefer to steer clear.

The ingredient is produced entirely from petroleum-derived gases, so it contains no animal material and is therefore suitable for vegans and vegetarians.

Current safety assessments show no specific risks for pregnant or breastfeeding women when the ingredient is used in typical cosmetic amounts. Still, this is not medical advice and anyone who is expecting or nursing should run any skincare product past a doctor just to be safe.

Peg/Ppg-160/31 Copolymer does not make skin more sensitive to sunlight, so it is not considered photosensitising. It is also odorless and free of common allergens such as gluten, soy and nuts which makes it compatible with many personal preferences and restrictions.

Potential Side Effects/Adverse Reactions

Side effects and reactions to the topical application of Peg/Ppg-160/31 Copolymer vary from person to person. The points below list potential issues yet they are uncommon when the ingredient is used at cosmetic levels and formulated correctly.

  • Mild skin irritation such as temporary redness or stinging in very sensitive individuals
  • Contact allergy presenting as rash or itching in people already allergic to PEGs or PPGs
  • Eye irritation if the raw ingredient splashes directly into the eyes before being diluted in a finished product
  • Enhanced penetration of other ingredients which could theoretically increase irritation from harsher actives included in the same formula

If any unwanted reaction occurs stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 0 / 5

Peg/Ppg-160/31 Copolymer is highly water soluble and leaves little to no oily residue on the skin, which means it does not block pores. Its large molecular size further limits the chance of it settling into follicles. For these reasons formulators classify it as non-comedogenic.

Because it scores a zero this ingredient is generally suitable for people who are prone to acne or breakouts.

No extra concerns have been raised regarding its effect on pore blockage even when used daily in leave-on products.

Summary

Peg/Ppg-160/31 Copolymer is primarily a solvent that keeps both water-loving and oil-loving ingredients evenly dispersed. By dissolving actives, fragrances and preservatives it helps formulas stay clear, stable and lightweight so every application delivers consistent results.

While not the most famous name on an ingredient label it appears in a fair share of modern moisturizers, serums, conditioners and gentle cleansers because chemists appreciate its reliability and ease of use.

Current safety reviews show it is low risk for irritation or allergy when used at cosmetic levels. Still, skin can be unpredictable so it is smart to patch test any new product containing this copolymer before full use.

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