Methoxy Peg-100/Polyepsilon Caprolactone Palmitate: 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
Share:
Inside this article:

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 Methoxy Peg-100/Polyepsilon Caprolactone Palmitate?

Methoxy PEG-100/Polyepsilon Caprolactone Palmitate is a laboratory-crafted block copolymer made by linking methoxy-terminated polyethylene glycol units with segments of poly-epsilon-caprolactone that have been esterified with palmitic acid. The raw materials are usually petroleum-derived ethylene oxide, bio-based or synthetic caprolactone, and plant or palm-sourced palmitic acid. Chemists combine these building blocks through controlled ring-opening polymerization then finish the chain with methoxy groups so the polymer disperses evenly in water-based formulas.

The ingredient first appeared in the early 2000s when formulators were searching for kinder alternatives to stiff hair sprays that still offered reliable hold. Its balanced water-loving and oil-loving structure quickly made it popular in styling products then in skin care where a soft, breathable film was desirable. Today it can be found in lightweight day creams, setting sprays, leave-in conditioners, wash-off masks, tinted moisturizers and anti-frizz serums.

Methoxy Peg-100/Polyepsilon Caprolactone Palmitate’s Cosmetic Benefits/Uses

This multi-tasking polymer offers several perks when added to beauty formulas:

  • Buffering – helps keep the final product’s pH steady so the formula stays gentle and active ingredients remain stable
  • Film forming – creates a thin flexible layer on skin or hair that locks in moisture reduces transepidermal water loss and gives makeup longer wear
  • Hair conditioning – smooths the hair cuticle for a softer feel and improved shine making combing easier and cutting down on static
  • Hair fixing – provides light to medium hold in styling products allowing hair to keep its shape without flaking or feeling stiff

Who Can Use Methoxy Peg-100/Polyepsilon Caprolactone Palmitate

Because this polymer is lightweight and non-occlusive it tends to agree with most skin types including dry, normal and oily skin. Its gentle pH buffering action also makes it a friendly option for sensitive complexions that react to harsher hold agents. People with extremely acne-prone skin might prefer a simpler formula since any film former can add an extra layer that traps sweat or sebum under heavy conditions, yet the risk is low in well-balanced products.

The raw materials are usually synthetic or plant derived which means the finished ingredient can be suitable for vegans and vegetarians as long as the manufacturer sources palmitic acid from palm or other plant oils rather than animal fat. Brands that are certified vegan should specify this on the label.

No research links Methoxy PEG-100/Polyepsilon Caprolactone Palmitate to reproductive or developmental concerns. The molecule is large and stays on the surface of skin or hair so absorption is minimal. Still, pregnant or breastfeeding individuals should check any new cosmetic with their healthcare provider first since this article is not medical advice.

The polymer is not known to cause photosensitivity and does not interact with UV rays, so daytime use does not require special sun precautions beyond normal sunscreen habits.

Potential Side Effects/Adverse Reactions

Reactions to topical Methoxy PEG-100/Polyepsilon Caprolactone Palmitate differ from person to person. The points below list potential side effects yet most users will not notice any problems when the ingredient is formulated correctly.

  • Mild skin redness or stinging on very sensitive skin
  • Rare cases of allergic contact dermatitis due to the PEG portion or trace impurities
  • Occasional clogged pores or small breakouts if applied in thick layers on acne-prone areas
  • Product buildup on hair that can leave strands feeling coated if not washed out regularly
  • Eye irritation if the raw polymer dust is handled directly during DIY processing

If any discomfort, rash or persistent buildup occurs stop using the product and seek advice from a healthcare professional or qualified dermatologist.

Comedogenic Rating

Rating: 1 / 5. This polymer sits on the surface in a light breathable layer and has no oily fatty acid chains that typically clog pores. The PEG backbone keeps it water dispersible which lowers the chance of it mixing with sebum and hardening inside follicles. A rating of 1 signals a very low likelihood of causing blackheads or whiteheads yet not a complete zero because any film former can trap debris if layered heavily in humid conditions. Overall it is considered safe for those prone to acne or breakouts in well-balanced formulas.

Because the ingredient is often used at modest levels and easily washes off with regular cleansing, long-term buildup is unlikely. Still, people living in hot climates or who use many leave-on products might notice minor congestion if they skip routine cleansing.

Summary

Methoxy PEG-100/Polyepsilon Caprolactone Palmitate buffers pH so actives stay effective, forms a soft flexible film that locks in moisture and extends makeup wear, conditions hair by smoothing the cuticle for added shine and slip and fixes styles with light hold that resists flaking. It performs these roles thanks to its block structure that pairs water-loving PEG segments with oil-friendly caprolactone-palmitate blocks giving it a balanced affinity for both phases.

You will not see this polymer splashed across marketing campaigns but formulators appreciate its versatility so it quietly shows up in an increasing number of creams, sprays and leave-ins.

Safety data to date shows a low irritation profile and negligible absorption which makes the ingredient suitable for daily use on most skin and hair types. As with any new cosmetic though it is smart to perform a small patch test when trying a product featuring Methoxy PEG-100/Polyepsilon Caprolactone Palmitate just to be on the safe side.

Was this article helpful?
More from Glooshi:
ADVERTISEMENT
Get all our top headlines in beauty.
Delivered right to your inbox each week. Zero spam, all goodness, opt-out at anytime.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Get the latest beauty news, top product recommendations & brand-exclusive discount codes direct to your inbox.
Send good feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Send bad feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Search