PEG-400 is a low-molecular-weight polyethylene glycol used as a functional cosmetic ingredient in skincare, haircare, cleansing and other personal-care formulations. It is a highly water-compatible, non-ionic polyether material valued for its solvent, solubilizing, emulsion-stabilizing, binding and formulation-support properties.
PEG-400 belongs to the polyethylene glycol family and is identified by the INCI name PEG-400. The “400” designation refers to the approximate average molecular-weight level of the material rather than indicating 400 repeating ethylene oxide units in every polymer molecule.
PEG-400 is generally supplied as a clear, colorless to nearly colorless liquid with good water compatibility. Its combination of moderate molecular weight, low-to-moderate viscosity and hydrophilic character makes it useful in a wide range of cosmetic formulations.
PEG-400 can support the incorporation and distribution of compatible ingredients, including selected cosmetic functional ingredients, fragrance materials and colorants. It can also contribute to the consistency and physical stability of certain formulation systems.
PEG-400 is a polyethylene glycol with an average molecular weight of approximately 400 g/mol. Its INCI designation is PEG-400 and its CAS number is 25322-68-3.
Polyethylene glycols are polymeric materials consisting of repeating oxyethylene units. PEG-400 is not a single molecular compound with one fixed chain length; rather, commercial PEG-400 consists of a distribution of polyethylene glycol chain lengths centered around the specified average molecular-weight range.
A generic representation is:
HO–(CH₂CH₂O)n–H
where n represents the number of repeating oxyethylene units.
For a PEG material around molecular weight 400, the average chain corresponds to approximately 8–9 oxyethylene units, although the commercial material contains a distribution of molecular sizes.
PEG-400 should be distinguished from PEG-400 derivatives, including:
These ingredients have different chemical structures and should not be represented as plain PEG-400.
PEG-400 can be represented by the general structure:
HO–(CH₂CH₂O)n–H
The material contains repeating ethylene oxide-derived units terminated by hydroxyl groups.
Unlike a small-molecule ingredient with a single molecular weight, PEG-400 is a polymeric distribution. The commercial product therefore contains molecules of different chain lengths around the average molecular-weight range.
This molecular distribution affects:
As PEG molecular weight increases, the material generally becomes more viscous and progressively changes from liquid toward waxy or solid forms. COSMILE Europe notes that PEGs with mean molar masses up to approximately 600 g/mol are generally liquid, while higher molecular-weight materials become progressively more wax-like or solid.
PEG-400 is widely useful as a solvent for compatible cosmetic ingredients.
Its hydrophilic structure allows it to assist in dissolving or distributing selected components within water-containing formulations.
It can be considered for formulations containing:
The actual solvency depends on the chemical nature of the ingredient being incorporated and the overall formulation.
PEG-400 can support the solubilization and distribution of compatible ingredients in cosmetic systems.
It is particularly useful where a water-compatible liquid carrier is required to help incorporate materials that have limited direct compatibility with the aqueous phase.
This makes PEG-400 relevant to:
COSMILE Europe specifically describes PEG-400 use in facial, shaving and hair lotions as a solvent and solubilizer for functional ingredients, perfume oils and colorants.
PEG-400 can contribute to formulation stability in appropriate systems.
It may support the physical consistency and stability of formulations when used together with suitable emulsifiers, surfactants, polymers and other formulation components.
However, plain PEG-400 should not automatically be classified as a primary emulsifier. Its contribution depends on the complete formulation architecture.
PEG-400 is also associated with binding functionality in cosmetic products.
It can contribute to the cohesion of certain formulation systems, particularly where a water-compatible polyethylene glycol is required.
PEG-400 can function as a functional excipient in fragrance-containing formulations.
It may help carry or distribute compatible fragrance materials and support their incorporation into appropriate cosmetic systems.
PEG-400 is hydrophilic and can contribute to moisture-related formulation properties. It may therefore be useful in formulations where moisture support is desirable.
However, for accurate cosmetic-function classification, the principal documented functions for PEG-400 should be treated as solvent, binding, emulsion stabilization and fragrance functional, while humectant/moisture-support effects depend on the formulation and use level.
PEG-400 may be considered for:
PEG-400 can be incorporated into selected hair-care systems where solvent and formulation-support functionality is required.
Potential applications include:
PEG-400 can support selected cleansing systems, including:
PEG-400 may be used in:
PEG-400 may also support:
COSMILE Europe identifies PEG-400 in facial, shaving and hair lotions and describes its use as a solvent and solubilizer for functional ingredients, fragrance oils and colorants.
PEG-400 is a polymeric material characterized by an average molecular-weight designation.
The commercial material contains a distribution of molecular sizes, so the exact grade should be evaluated using its current technical documentation.
Important parameters include:
PEG-400 is normally supplied as a liquid at room temperature.
Its liquid form provides convenient handling and incorporation into aqueous and water-containing formulations.
PEG-400 has strong compatibility with water and is suitable for many aqueous cosmetic systems.
Its water compatibility is one of the major reasons for its use as a solvent and solubilizing ingredient.
PEG-400 can absorb moisture from the surrounding environment.
For commercial storage:
PEG-400 has higher viscosity than lower-molecular-weight PEG grades such as PEG-200.
The viscosity of PEG-400 is also temperature-dependent.
Therefore, processing conditions should account for:
There is no universal cosmetic concentration for PEG-400.
The appropriate level depends on:
The finished formulation should be tested for stability, appearance, viscosity and sensory properties.
PEG-400 does not have one universal finished-product pH.
The pH of a cosmetic formulation depends on the complete system, including water phase, active ingredients, preservatives and other formulation components.
The finished product should therefore be evaluated using the appropriate validated pH method.
PEG-400 should be evaluated for compatibility with:
Compatibility testing should be performed under actual formulation conditions.
Depending on the commercial grade and intended application, important quality-control parameters may include:
Exact numerical limits should be taken from the applicable commercial grade and current COA/TDS rather than treated as universal values.
Swapnroop Drugs & Pharmaceuticals supplies cosmetic and formulation ingredients for manufacturers, formulators and personal-care businesses.
PEG-400 can be considered for customers seeking a PEG-400 cosmetic ingredient manufacturer in India for applications involving solvent functionality, solubilization, formulation support, binding and emulsion-stabilizing applications.
For commercial procurement, buyers should confirm the required PEG-400 grade, specification, packaging, application, documentation and quality requirements before purchase.
PEG-400 is a low-molecular-weight polyethylene glycol used as a cosmetic ingredient, primarily for solvent, solubilizing, binding and formulation-support applications.
The CAS number associated with plain PEG-400 is 25322-68-3.
The INCI name is PEG-400.
The “400” designation refers to the approximate average molecular-weight level of the polyethylene glycol material. It does not mean that every PEG-400 molecule contains exactly 400 ethylene oxide units.
PEG-400 has an average chain corresponding approximately to 8–9 oxyethylene units, while the commercial material contains a distribution of chain lengths.
PEG-400 is recognized for functions including solvent, binding, emulsion stabilization and fragrance functional applications.
Yes. PEG-400 is generally supplied as a clear, colorless liquid at normal room temperature.
Yes. PEG-400 has strong water compatibility and is suitable for many aqueous and water-containing formulations.
PEG-400 can be used in selected skincare, haircare, facial, shaving, cleansing, fragrance and other personal-care formulations.
Yes. Solvent is one of the recognized cosmetic functions of PEG-400.
PEG-400 is hydrophilic and can contribute to moisture-related formulation properties, but its principal documented cosmetic functions include solvent, binding, emulsion stabilization and fragrance-functional roles.
| Parameter | Specification |
|---|---|
| Appearance | Colourless to light-yellow liquid or oily liquid |