What Is Methoxy Peg-100/Epsilon Caprolactone/Sebacate Copolymer?
Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer is a synthetic block copolymer created by linking three distinct building blocks: methoxy-terminated polyethylene glycol with an average molecular weight of 100, epsilon caprolactone, and sebacic acid. Chemists combine these components through controlled ring-opening polymerization and esterification, resulting in a flexible chain that carries both water-loving and oil-loving segments. This balance lets the copolymer interact well with a wide range of cosmetic ingredients.
The earliest uses of similar PEG-based copolymers were in medical devices where their biocompatibility and moisture management were prized. As formulators looked for gentler alternatives to heavy occlusive agents, the cosmetic industry adopted this ingredient for its lightweight feel and strong moisture attraction. Today it is produced in specialized facilities that carefully adjust reaction time, temperature and catalyst levels to achieve consistent molecular weight and purity, followed by filtration and drying steps to remove residual monomers.
You will most often spot Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer in leave-on skincare such as moisturizers, serums, sheet masks and soothing after-sun gels. It also appears in hydrating primers, lightweight foundations and hair-conditioning sprays where an invisible moisture veil is desired without greasiness.
Methoxy Peg-100/Epsilon Caprolactone/Sebacate Copolymer’s Cosmetic Benefits/Uses
This ingredient is prized mainly for one standout role in formulas.
As a humectant it draws water from both the environment and deeper skin layers to the surface of the skin, helping maintain optimal hydration levels. By keeping the stratum corneum supple it softens rough patches, supports a smoother texture and can enhance the plumping effect of other actives. Its lightweight nature means it delivers this hydration boost without a sticky after-feel, making products more comfortable for daily use and suitable for layering under makeup.
Who Can Use Methoxy Peg-100/Epsilon Caprolactone/Sebacate Copolymer
This humectant is gentle enough for most skin types. Dry and dehydrated skin benefit most from its moisture binding ability while normal and combination skin appreciate the lightweight feel. Oily and acne-prone skin can use it because it does not form a heavy film that might clog pores. Those with very reactive or medically compromised skin should still check the full formula for added fragrances or acids that could be troublesome, but the copolymer itself is not known to be irritating.
The ingredient is made through synthetic chemistry with no animal-derived components so it is generally suitable for vegans and vegetarians. As always consumers should confirm that the finished product is certified cruelty free and free of other animal ingredients.
No specific warnings exist for use during pregnancy or while breastfeeding. The molecule is large, sits on the surface of the skin and is considered low risk, yet this is not medical advice. Expectant or nursing mothers should run any skincare routine past their doctor to be safe.
Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer does not cause photosensitivity, so standard daytime sun protection practices are all that is required.
The ingredient plays well with most actives and preservatives, making it a flexible choice for a wide range of formulations.
Potential Side Effects/Adverse Reactions
Side effects from topical Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer vary from person to person. The following is a list of potential reactions, though they are uncommon when the ingredient is used correctly in a well-formulated product.
- Mild redness or stinging on extremely sensitive skin
- Temporary tacky sensation if applied in very high concentrations
- Rare contact dermatitis in individuals with a known sensitivity to PEGs
- Eye irritation if the product accidentally gets into the eyes
If any negative reaction occurs discontinue use and consult a healthcare professional
Comedogenic Rating
Rating: 0 / 5
Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer is a water-attracting polymer that sits lightly on the skin without forming a thick occlusive film. It lacks heavy oils or waxes and its large molecular size keeps it on the surface rather than sinking into pores. These factors give it virtually no tendency to block follicles, so it is considered non-comedogenic.
Because of this low rating it is generally suitable for people prone to acne or breakouts.
The ingredient also rinses away cleanly in cleansers and leaves only a thin, breathable layer in leave-on products, further reducing any clogging risk.
Summary
Methoxy PEG-100/Epsilon Caprolactone/Sebacate Copolymer is used in cosmetics mainly as a humectant that pulls moisture to the skin’s surface, softens rough texture and boosts the plumping effect of other hydrators. Its balanced structure of water-loving and oil-compatible segments lets it blend smoothly into many formulas while keeping the finish light and non-greasy.
Although not yet a household name it is gaining popularity among formulators who want a gentle alternative to heavier hydrators in moisturizers, serums and makeup primers.
Safety studies show a low risk of irritation or sensitization and its comedogenic rating is virtually zero. As with any new skincare product a quick patch test is a smart step before full-face application just to be on the safe side.