Cetyl Phosphate is a compound used to structure certain emulsions and enhance the sensory characteristics of cosmetic products. Although not widely known to the general public, it directly contributes to the quality of formulations. What exactly is the role of Cetyl Phosphate for the skin and in formulation? We explain everything here.
What is “Cetyl Phosphate” and what is it used for?
Summary
Published on February 16, 2026, updated on February 16, 2026, by Pauline, Chemical Engineer — 5 min of reading
Themes:
Key points to remember about Cetyl Phosphate.
Cetyl Phosphate primarily acts as an emulsifier, enabling the stabilisation of formulations containing an aqueous phase and an oil phase, such as moisturising creams.
Cetyl Phosphate is also capable of promoting organisation into lamellar liquid crystal structures, which improves skin hydration.
The available scientific data indicate very good skin tolerability of Cetyl Phosphate, with no reported cases of irritation or sensitisation.
Toxicological assessments show that Cetyl Phosphate is neither genotoxic nor mutagenic nor an eye irritant, confirming its good safety profile.
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Overview of Cetyl Phosphate.
Cetyl Phosphate is a compound of synthetic origin belonging to the family of phosphoric esters of fatty alcohols. Its structure is based on the combination of a long alkyl chain, typically sourced from cetyl alcohol (a 16-carbon fatty alcohol), and an ionisable phosphate group. This arrangement gives the molecule an amphiphilic nature, that is, it possesses both a lipophilic portion, attracted to oils, and a hydrophilic portion capable of interacting with water.
Chemical structure of Cetyl Phosphate.
Source: PubChem.
From a functional standpoint, this molecular architecture confers a specific affinity for interfaces between phases of differing polarity, as well as the ability to organise into ordered structures such as micelles or lamellar layers. These properties notably depend on the pH of the medium, which determines the ionisation state of the phosphate group and hence the possible electrostatic interactions with other molecules. Furthermore, the presence of a relatively long saturated hydrocarbon chain contributes to the thermodynamic stability of these molecular organisations.
| Chemical and physical properties | Values |
|---|---|
| Chemical formula | C16H35O4P |
| Names | Cetyl phosphate, hexadecyl dihydrogen phosphate, hexadecyl phosphate, 1-hexadecanol dihydrogen phosphate, monocetyl phosphate, cetyl dihydrogen phosphate, phosphoric acid monohexadecyl ester, monocetylphosphoric acid |
| Aspect | White to beige powder, odourless |
| Molar mass | 322.42 g/mol |
| Dosage | Generally used at concentrations between 0.5% and 3% |
| Solubility | Partially soluble in water, disperses in hot water, yielding clear to slightly opaque solutions that gel on cooling |
Physico-chemical characteristics of Cetyl Phosphate.
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Why use Cetyl Phosphate in cosmetics?
Within cosmetic formulations, Cetyl Phosphate is primarily utilised for its emulsifying properties.
Indeed, when formulating a moisturising cream for example, it is necessary to combine an aqueous phase with an oil phase. However, these two phases are not normally miscible. Thanks to its amphiphilic structure, Cetyl Phosphate reduces the interfacial tension between these two phases and allows for the fine dispersion of one into the other in the form of microdroplets. This arrangement limits the separation phenomenon over time and thus contributes to the physical stability of the emulsion, an essential parameter to ensure the efficacy, safety and sensory quality of a skincare product.
Schematic representation of an emulsion.
Source: AJAYI O. Thermodynamic and kinetic stability of cosmetic nanoemulsions. Nanoemulsions - Design and Applications (2024).
Furthermore, Cetyl Phosphate contributes to the even spreading of skincare products on the skin. It enhances the perceived texture during application and adds to user comfort. Some pharmaceutical formulation studies also show that this type of phospholipid can promote the formation of liquid crystalline lamellar structures, resembling the lipid organisation of the stratum corneum. These molecular arrangements are associated with improved water retention in the epidermis and convey a hydrating effect.
What is the safety profile of Cetyl Phosphate?
Cetyl Phosphate is a cosmetic ingredient that is very well tolerated.
It indeed has a reassuring safety profile. To date, the scientific literature does not report any documented case of skin reaction attributed to this ingredient, suggesting very good skin tolerance under normal conditions of use. The safety evaluations carried out on Cetyl Phosphate also demonstrate the absence of genotoxicity and mutagenicity, two essential criteria for ruling out long-term risk. These analyses further conclude that the substance neither behaves as a skin sensitiser nor as an eye irritant. All of these elements help to explain its widespread use in skincare products.
Note : In cosmetics, Potassium Cetyl Phosphate is also used; it has properties similar to those of Cetyl Phosphate and is somewhat more stable. However, it is associated with a higher risk of skin irritation.
Sources
DOS REIS SERRA C. H. & al. Emulsified systems based on glyceryl monostearate and potassium cetyl phosphate: Scale-up and characterization of physical properties. International Journal of Pharmaceutics (2008).
HELDRETH B. & al. Safety assessment of alkyl phosphates as used in cosmetics. International Journal of Toxicology (2019).
MAIA CAMPOS P. & al. Optimization of cosmetic formulations development using Box-Behnken design with response surface methodology: Physical, sensory and moisturizing properties. Brazilian Journal of Pharmaceutical Sciences (2020).
AJAYI O. Thermodynamic and kinetic stability of cosmetic nanoemulsions. Nanoemulsions - Design and Applications (2024).
