Cetyl Phosphate is a compound used to structure certain emulsions and improve the sensory feel of cosmetic products. Although it is 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 it all here.
What is “Cetyl Phosphate” and what is its purpose?
Summary
Published on February 16, 2026, updated on February 16, 2026, by Pauline, Chemical Engineer — 5 min of reading
Themes:
The key points to remember about Cetyl Phosphate.
Cetyl Phosphate primarily acts as an emulsifier, allowing the stabilization of formulations containing an aqueous phase and an oil phase, such as moisturizing creams.
Cetyl Phosphate is also capable of promoting the organization into lamellar structures of the liquid crystal type, which enhances skin hydration.
The available scientific data indicate a very good skin tolerance of Cetyl Phosphate, with no reported cases of irritation or sensitization.
Toxicological assessments show that Cetyl Phosphate is neither genotoxic, mutagenic, nor an ocular irritant, confirming its favorable safety profile.
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An overview of Cetyl Phosphate.
Cetyl Phosphate is a synthetic compound belonging to the family of phosphoric esters of fatty alcohols. Its structure is based on the combination of a long alkyl chain, typically derived from cetyl alcohol (a 16-carbon fatty alcohol), and an ionizable phosphate group. This arrangement gives the molecule an amphiphilic nature, meaning it has 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 grants it a particular affinity for interfaces between phases of different polarity, as well as the ability to organize into ordered structures such as micelles or lamellar layers. These properties depend in particular on the pH of the medium, which governs the ionization state of the phosphate group and thus the potential electrostatic interactions with other molecules. Moreover, the presence of a relatively long saturated fatty chain contributes to the thermodynamic stability of these molecular assemblies.
| Chemical and physical characteristics | 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 |
| Appearance | White to beige powder, odorless |
| Molar mass | 322,42 g/mol |
| Dosage | Generally used between 0.5% and 3% |
| Solubility | Partially soluble in water, disperses in hot water to yield clear to slightly opaque solutions that gel upon cooling |
Physicochemical characteristics of Cetyl Phosphate.
Why use Cetyl Phosphate in cosmetics?
In cosmetic formulations, Cetyl Phosphate is primarily used for its emulsifying properties.
Indeed, when formulating a moisturizing cream for example, it is necessary to combine an aqueous phase and an oil phase. However, these two phases are normally immiscible. Thanks to its amphiphilic structure, Cetyl Phosphate reduces the interfacial tension between these two phases and enables the fine dispersion of one phase into the other in the form of microdroplets. This arrangement minimizes separation over time and thus contributes to the physical stability of the emulsion, an essential parameter for ensuring the efficacy, safety, and sensory quality of a skin care product.
Schematic representation of an emulsion.
Source: AJAYI O. Thermodynamic and kinetic stability of cosmetic nanoemulsions. Nanoemulsions - Design and Applications (2024).
Furthermore, Cetyl Phosphate aids in the smooth spreadability of skincare products on the skin. It enhances the perceived texture during application and contributes to user comfort. Some formulation studies have also shown that this type of phospholipid can promote the formation of lamellar liquid-crystal structures resembling the lipid organization of the stratum corneum. These molecular arrangements are associated with improved water retention in the epidermis, reflecting 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 reports no documented cases of skin reactions attributed to this ingredient, suggesting very good skin tolerance under normal use conditions. Safety assessments conducted 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 does not act as a skin sensitizer or an ocular irritant. Taken together, these findings help explain its widespread use in skincare products.
Note : Potassium Cetyl Phosphate is also used in cosmetics; it has properties similar to Cetyl Phosphate and is slightly more stable. However, it is associated with an increased 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).
