PEG-40 is a polyethylene glycol-based cosmetic ingredient identified by the INCI name PEG-40. It belongs to the polyethylene glycol family and is primarily used as a humectant and solvent in cosmetic and personal-care formulations.
The number “40” indicates an average of approximately 40 ethylene oxide-derived molecular units in the material. PEG-40 therefore represents an average polymeric composition rather than a single molecular species in which every molecule contains exactly 40 units.
PEG-40 is a hydrophilic, water-compatible ingredient that can support moisture retention and the incorporation of selected cosmetic ingredients into suitable formulation systems. It is particularly relevant to skincare, haircare, toners and other personal-care formulations.
The recognized CAS number for plain PEG-40 is 25322-68-3. The same broad CAS number can also appear in documentation for other polyethylene glycol molecular-weight ranges, so the INCI name, average molecular characteristics and commercial-grade documentation should be considered together.
PEG-40 is a polyethylene glycol material with an average ethylene oxide-unit value of approximately 40. Polyethylene glycols are polymeric materials containing a distribution of molecular species around their stated average.
PEG-40 provides:
Its hydrophilic nature allows it to interact with water and makes it useful in aqueous and polar cosmetic systems.
PEG-40 should be clearly distinguished from ingredients that contain “PEG-40” as part of a longer INCI name. For example, PEG-40 Stearate, PEG-40 Castor Oil and PEG-40 Hydrogenated Castor Oil are chemically different PEG derivatives and should not be treated as plain PEG-40.
| Property | Details |
|---|---|
| Product Name | PEG-40 |
| INCI Name | PEG-40 |
| Chemical Family | Polyethylene Glycols |
| Chemical Type | Polyethylene glycol |
| CAS Number | 25322-68-3 |
| CosIng Reference | 78449 |
| Average Ethoxylation | Approximately 40 ethylene oxide units |
| Chemical Description | Poly(oxy-1,2-ethanediyl), alpha-hydro-omega-hydroxy-, 40 mol EO average molar ratio |
| Synonyms | Polyethylene Glycol 40, Polyoxyethylene 40 |
| Physical State | Grade-dependent; typically viscous liquid to wax-like material |
| Appearance | Typically clear to colorless or slightly colored; grade-dependent |
| Origin | Synthetic |
| Water Compatibility | Hydrophilic / water-compatible |
| Primary Functions | Humectant, Solvent |
| Molecular Weight | Average/distribution-dependent |
| Molecular Composition | Average polymeric composition |
| Commercial Grade | Grade-specific |
PEG-40 can help retain moisture within cosmetic formulations. Its hydrophilic polyethylene glycol structure provides affinity for water and supports hydration-oriented formulations.
PEG-40 can dissolve or assist in incorporating selected cosmetic ingredients into compatible formulation systems. This makes it useful when a water-compatible solvent is required.
PEG-40 can support the incorporation of compatible functional ingredients, fragrance materials and other formulation components into aqueous or polar systems.
PEG-40 can contribute to moisture management in cosmetic products where a polyethylene glycol-based humectant is appropriate.
PEG-40 may function as a supporting ingredient in fragrance-containing cosmetic systems where solvent or formulation functionality is required.
PEG-40 can be considered for a variety of cosmetic and personal-care applications.
PEG-40 can be evaluated where a hydrophilic polyethylene glycol material is needed for humectant or solvent functionality.
The “40” represents an average ethylene oxide-unit value. It does not mean that every molecule in the material contains exactly 40 units.
Commercial PEG materials contain a molecular-weight distribution around the stated average. The exact molecular characteristics should therefore be controlled according to the selected commercial grade.
Compared with lower-average PEG grades, PEG-40 can have a higher viscosity and may exhibit a wax-like or semi-solid character depending on the molecular-weight distribution and temperature.
PEG-40 is hydrophilic and suitable for compatible aqueous and polar formulation systems.
The appropriate use level should be established through formulation development and compatibility testing based on the intended product.
Compatibility should be evaluated with:
The finished formulation pH should be evaluated according to the complete formulation. A universal pH value should not be assigned solely to PEG-40.
Depending on the commercial grade, quality evaluation may include:
PEG-20: Lower average ethylene oxide-unit value than PEG-40.
PEG-32: Lower average ethylene oxide-unit value than PEG-40.
PEG-40: Average value of approximately 40.
PEG-60: Higher average ethylene oxide-unit value than PEG-40.
PEG-40 Stearate: A stearic-acid PEG ester and chemically different from plain PEG-40. It functions primarily as a surfactant/emulsifier.
PEG-40 Castor Oil: An ethoxylated castor-oil derivative and chemically different from PEG-40.
PEG-40 Hydrogenated Castor Oil: A hydrogenated castor-oil-derived PEG ingredient and chemically different from PEG-40.
These distinctions are important when selecting ingredients, preparing technical documents and creating accurate cosmetic product pages.
Swapnroop provides cosmetic ingredient solutions for manufacturers and formulators developing skincare, haircare and personal-care products.
PEG-40 can be considered for formulations requiring a polyethylene glycol ingredient with humectant and solvent functionality. The selected grade should be evaluated according to its molecular characteristics, viscosity, physical form, purity and intended application.
For bulk procurement and formulation development, customers should review the applicable COA, TDS and product specification for the exact PEG-40 commercial grade.
PEG-40 is a polyethylene glycol cosmetic ingredient with an average value of approximately 40 ethylene oxide-derived molecular units.
The CAS number associated with plain PEG-40 is 25322-68-3.
The INCI name is PEG-40.
The CosIng reference for PEG-40 is 78449.
PEG-40 is primarily used as a humectant and solvent.
The number 40 represents the average value of ethylene oxide-derived molecular units in the polyethylene glycol material.
No. PEG-40 Stearate is a stearic-acid ester of polyethylene glycol and has a different chemical identity and formulation role.
No. PEG-40 Hydrogenated Castor Oil is an ethoxylated hydrogenated castor-oil derivative and is chemically different from plain PEG-40.
PEG-40 is hydrophilic and can be used in suitable water-containing and polar formulation systems.
No. PEG-40 represents an average polymeric composition, so its molecular-weight distribution depends on the commercial grade.
PEG-40 can be used in skincare, haircare, toners, moisturizers, hair tonics and other personal-care formulations where humectant or solvent functionality is required.
| Parameter | Specification |
|---|---|
| Appearance | Colourless to light-yellow liquid or oily liquid |