What Is Peg-100?
Peg-100 is a synthetic ingredient whose full chemical name is poly(oxy-1,2-ethanediyl) .alpha.-hydro-.omega.-hydroxy- with an average of 100 ethylene oxide units strung together. It belongs to the large family of polyethylene glycols, materials created by reacting ethylene oxide with water or ethylene glycol under controlled heat and pressure. The number 100 simply indicates the average length of the chain, giving the material a creamy, wax-like consistency that dissolves easily in water and some oils.
The raw feedstock for Peg-100 usually starts with petroleum-derived ethylene, though some manufacturers now use bio-based ethylene sourced from sugarcane or corn. First produced in the mid-20th century for industrial applications, polyethylene glycols quickly found their way into personal care products because they are gentle, versatile and highly compatible with other ingredients. Peg-100’s balanced molecular weight makes it especially useful in skin care, hair care and color cosmetics.
You will most often see Peg-100 in moisturizers, face masks, serums, lotions, shampoos, conditioners and makeup removers. It helps these formulas feel smooth, spread evenly and stay stable on the shelf.
Peg-100’s Cosmetic Benefits/Uses
Formulators choose Peg-100 because it delivers two main benefits that improve the performance and feel of a product.
- Humectant: Peg-100 attracts and holds water from the surrounding environment. This boost in moisture helps keep skin and hair hydrated leaving them feeling softer and more supple.
- Solvent: It dissolves or disperses other ingredients that might otherwise clump or separate. By keeping fragrances, active ingredients and pigments evenly mixed Peg-100 ensures a uniform application and a stable formula.
Who Can Use Peg-100
Peg-100 is generally considered suitable for all skin types including oily, combination, normal, dry and even sensitive skin because it has a low risk of clogging pores and a mild, non-irritating profile. Those with severely broken or compromised skin barriers should still use caution since any polyethylene glycol can increase penetration of other ingredients.
The ingredient is synthetic and typically sourced from petroleum or plant-derived ethylene. No animal by-products are used in its manufacture which makes Peg-100 acceptable for vegans and vegetarians.
No specific warnings exist for pregnant or breastfeeding women when it comes to topical Peg-100. It is widely used in personal care items sold in drugstores and baby products. That said this is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of any new product to a qualified health professional before regular use.
Peg-100 is not known to cause photosensitivity. Users do not need additional sun protection because of this ingredient beyond what is already recommended for daily skincare.
Potential Side Effects/Adverse Reactions
Reactions to Peg-100 differ from one person to another. The points below list potential side effects but most people will not notice any problems when the ingredient is used at common cosmetic levels in a well-formulated product.
- Skin irritation: Mild redness, itching or stinging can occur especially on compromised skin
- Allergic contact dermatitis: Rare but possible in individuals with a specific sensitivity to polyethylene glycols
- Dryness: Overuse in very high concentrations might draw water away from the skin instead of into it
- Enhanced penetration of other substances: On damaged skin Peg-100 may increase the absorption of actives or impurities which could amplify their effects
If any of these reactions appear stop using the product and consult a healthcare professional if symptoms persist or worsen.
Comedogenic Rating
Rating: 0 (non-comedogenic)
Peg-100 is highly water soluble and has a relatively large molecular size so it sits on the surface then rinses or wipes away without blocking follicles. It is not an oil or wax that can harden inside pores which is why it earns a zero on the comedogenic scale.
Because it does not clog pores Peg-100 is generally suitable for people who struggle with acne or frequent breakouts.
The only caveat is the overall formula: if Peg-100 is blended with heavier butters or comedogenic oils the finished product could still cause congestion. Always look at the full ingredient list rather than judging by a single component.
Summary
Peg-100 acts mainly as a humectant and solvent. It pulls in water to keep skin and hair hydrated and it dissolves or evenly disperses other ingredients so a product feels smooth applies easily and stays stable on the shelf.
Thanks to these dependable qualities Peg-100 appears in a wide variety of moisturizers cleansers masks and hair products. It is not a headline-grabbing additive but formulators rely on it every day because it does its job quietly and well.
The ingredient has a long record of safe topical use with low irritation potential when used at normal cosmetic levels. Still every skin is different so patch testing a new product is a smart habit even when it contains a gentle helper like Peg-100.