What Is Steareth-100/Peg-136/Hdi Copolymer?
Steareth-100/PEG-136/HDI Copolymer is a synthetic polymer created by linking together long chains of ethylene oxide (PEG units), stearyl alcohol derivatives and hexamethylene diisocyanate. This combination forms a large, flexible molecule that blends water-loving and oil-loving segments, allowing it to interact with both phases of a cosmetic formula. First developed by specialty chemical suppliers in the late 1990s, it gained popularity as brands sought more stable, lightweight textures for creams and lotions. Production starts with controlled polymerization of ethylene oxide to reach an average length of 136 units, which is then reacted with stearyl alcohol and finally cross-linked with hexamethylene diisocyanate under carefully monitored temperature and pH conditions. The finished solid is purified, milled into a fine powder and supplied to manufacturers.
You will most often see this ingredient in emulsions such as facial moisturizers, body lotions, sunscreens, primers, sheet mask serums and leave-on hair conditioners where formulators need to fine-tune thickness without adding greasiness.
Steareth-100/Peg-136/Hdi Copolymer’s Cosmetic Benefits/Uses
In skin and hair care formulas this polymer serves one main purpose.
Viscosity controlling: It adjusts and stabilizes the thickness of a product so creams feel rich yet spread easily lotions stay fluid without separating and serums keep a silky flow. By holding the emulsion together it also helps active ingredients stay evenly distributed for consistent performance from the first pump to the last.
Who Can Use Steareth-100/Peg-136/Hdi Copolymer
This polymer is considered suitable for nearly all skin types including oily, combination, normal and dry skin because it does not add oil or strip moisture. Sensitive skin generally tolerates it well thanks to its large molecular size that keeps it on the surface rather than penetrating deeply. Those with very reactive or compromised skin should still review the full formula since irritation usually comes from other ingredients rather than the copolymer itself.
The material is produced from synthetic starting points with no animal derived components so it is typically regarded as vegan and vegetarian friendly. Brands may certify this status individually if their supply chain avoids animal testing and uses dedicated equipment.
Current safety assessments find no specific reproductive or developmental concerns linked to topical use so products containing this copolymer are considered acceptable for pregnant or breastfeeding individuals. This is not medical advice and anyone who is expecting or nursing should confirm product choices with a healthcare professional.
The polymer does not absorb UV light or trigger light-induced reactions so it is not known to cause photosensitivity. It is also odorless and non-volatile which minimizes inhalation concerns in sprays.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient can differ from person to person. The following list covers potential side effects associated with Steareth-100/PEG-136/HDI Copolymer but most users will not experience them when the product is properly formulated and used as directed.
- Mild skin irritation such as redness itching or stinging
- Allergic contact dermatitis in individuals already sensitized to polyethylene glycols or isocyanates
- Transient eye irritation if the product accidentally gets into the eyes
- Follicular congestion or acne flare in very acne-prone skin when used in heavy leave-on products
If you notice any persistent discomfort swelling rash or other unexpected reaction discontinue use and consult a medical professional.
Comedogenic Rating
Rating: 1/5
This copolymer is a large, water-soluble molecule that sits on the skin’s surface and is rinsed away easily, so it is very unlikely to clog pores. It does not add extra oils or waxes and is used at low levels, which keeps its pore-blocking potential minimal. For most acne-prone users it should be acceptable, though very heavy leave-on formulas that combine it with rich emollients could still feel occlusive on some skins.
No specific data shows the polymer itself feeding acne bacteria or worsening breakouts, and real-world reports of pimples linked solely to this ingredient are rare.
Summary
Steareth-100/PEG-136/HDI Copolymer is mainly a viscosity controller, giving creams body while letting lotions and serums stay smooth and stable. Its mixed water-loving and oil-loving structure positions itself at the oil-water boundary, strengthening the emulsion and preventing separation all the way through a product’s shelf life.
The ingredient enjoys moderate popularity: common enough to show up in mainstream moisturizers and sunscreens, yet not a buzzword on front labels since it works quietly behind the scenes.
Current safety reviews classify it as low risk for irritation or systemic harm when used as intended, making it a dependable choice for most consumers. Still, everyone’s skin is unique, so it is wise to patch test any new product that contains this polymer before full-face use.