PEG-400

PEG / Ethoxylated

What is PEG-400?

PEG-400, known chemically as polyethylene glycol with an average molecular weight of 400, is a synthetic polymer produced by the condensation of ethylene oxide with water. This results in a clear, colorless, hygroscopic liquid widely employed in the cosmetics sector across categories like moisturizers, cleansers, serums, and solid bars. Its polyether structure features repeating ethylene oxide units terminated by hydroxyl groups, conferring excellent solubility in water and many organic solvents. In formulations, PEG-400 dissolves lipophilic and hydrophilic ingredients alike, reduces viscosity for smoother application, binds powders into cohesive solids, and reinforces emulsion interfaces to prevent separation, thereby enhancing overall product integrity, spreadability, and longevity.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 3 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Binder
Helps hold solid ingredients together to form cohesive tablets, compacts, or sticks, improving pressability, integrity, and wear of the finished product.
Emulsion stabilizer
Improves emulsion robustness by preventing droplet coalescence and phase separation, often by thickening, structuring, or strengthening the interfacial layer.
Solvent
Dissolves and carries other ingredients, helping control viscosity, evaporation rate, and delivery of actives in both water- and oil-based systems.
Binding
Provides cohesion by helping ingredients stick together, improving the strength and integrity of pressed powders, tablets, or solid bars.

Benefits

Facilitates even blending of ingredients for uniform product consistency.

Supports stable emulsions, maintaining separation-free textures over time.

Aids in creating smooth, pressable solids like sticks and powders.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals seeking lightweight, fast-absorbing skincare textures.
People with known sensitivities to polyethers or ethoxylated compounds.
Users of multi-phase products like creams and lotions.
Individuals wary of ingredients with potential impurity risks.
Those preferring non-comedogenic solvents in daily routines.
Those preferring entirely natural or minimalist formulations.

Safety Notes

  • Assessed safe for cosmetic use by expert panels when formulated to minimize impurities.
  • Low comedogenic potential, unlikely to clog pores.

Frequently Asked Questions about PEG-400

What is PEG-400 derived from?

It is synthesized by polymerizing ethylene oxide, forming a water-soluble polyether chain.

Is PEG-400 comedogenic?

It carries a comedogenic rating of 0, indicating minimal risk of pore clogging.

Why is PEG-400 used in emulsions?

It strengthens interfacial layers, preventing droplet merging and phase instability.