Cosmetic Formulations and Ingredients

Cosmetics are formulated systems applied to external surfaces of the body, including the skin, hair, nails and lips, where they function essentially as temporary surface treatments or coatings. They may be designed to cleanse, protect, moisturize, condition, color, decorate, adhere to, alter the appearance of, or otherwise modify the properties of these surfaces.

Cosmetics are formulated systems applied to external surfaces of the body, including the skin, hair, nails and lips, where they function essentially as temporary surface treatments or coatings. They may be designed to cleanse, protect, moisturize, condition, color, decorate, adhere to, alter the appearance of, or otherwise modify the properties of these surfaces.

From a physical chemistry perspective, cosmetic formulations are dispersions often described as anhydrous systems, mixtures, solutions, structured systems,

Dispersions contain one phase distributed throughout another continuous phase. These include emulsions, in which one liquid is dispersed within another immiscible liquid, and suspensions, in which insoluble solid particles are dispersed within a liquid or semisolid continuous phase. Cosmetic examples include lotions and creams, pigmented foundations, sunscreens containing dispersed mineral particles, mascaras, and many color cosmetics.

Solutions are homogeneous systems in which one or more ingredients are dissolved at the molecular or ionic level within a continuous phase. Examples include aqueous toners, hydroalcoholic fragrances, some cleansers, and solutions of salts, acids, polymers, surfactants, or other soluble cosmetic ingredients.

Structured systems include gels, pastes, sticks, balms and other semisolid materials whose physical properties result from a three-dimensional network, high dispersed-phase concentration, crystallization, polymer association, particle interaction, or combinations of these mechanisms. A gel may therefore be based on an aqueous polymer network, an oil structured with a gelling agent, or another continuous phase. Wax-containing lipsticks, balms and sticks are examples of structured systems in which wax crystallization contributes to the mechanical properties of the formulation.

Anhydrous systems contain little or no intentionally added water. Examples include lipsticks, lip balms, oil-based serums, body oils, certain foundations, ointment-like cosmetic products, powders and some sticks. An anhydrous formulation may simultaneously be a solution, suspension, dispersion, gel or other structured system; “anhydrous” describes the absence of water rather than a separate physical state.

The final product form does not necessarily define the underlying formulation. For example, an adhesive may be a solution, emulsion, dispersion or structured polymer system before application and subsequently form an adhesive film on the skin. Similarly, an aerosol describes a method of product delivery rather than the fundamental formulation chemistry. The material contained within an aerosol package may itself be a solution, emulsion, suspension, powder or other formulated system that is dispensed using a compressed or liquefied propellant.

These classifications provide the physical-chemistry foundation for cosmetic formulation. Individual systems can then be defined according to their dispersed and continuous phases, rheology, interfacial properties, film formation, adhesion, stability and intended application.structured systems, or anhydrous systems, with considerable overlap between these classifications depending on composition and product structure.

Solutions are homogeneous systems in which one or more ingredients are dissolved at the molecular or ionic level within a continuous phase. Examples include aqueous toners, hydroalcoholic fragrances, some cleansers, and solutions of salts, acids, polymers, surfactants, or other soluble cosmetic ingredients.

Dispersions contain one phase distributed throughout another continuous phase. These include emulsions, in which one liquid is dispersed within another immiscible liquid, and suspensions, in which insoluble solid particles are dispersed within a liquid or semisolid continuous phase. Cosmetic examples include lotions and creams, pigmented foundations, sunscreens containing dispersed mineral particles, mascaras, and many color cosmetics.

Structured systems include gels, pastes, sticks, balms and other semisolid materials whose physical properties result from a three-dimensional network, high dispersed-phase concentration, crystallization, polymer association, particle interaction, or combinations of these mechanisms. A gel may therefore be based on an aqueous polymer network, an oil structured with a gelling agent, or another continuous phase. Wax-containing lipsticks, balms and sticks are examples of structured systems in which wax crystallization contributes to the mechanical properties of the formulation.

Anhydrous systems contain little or no intentionally added water. Examples include lipsticks, lip balms, oil-based serums, body oils, certain foundations, ointment-like cosmetic products, powders and some sticks. An anhydrous formulation may simultaneously be a solution, suspension, dispersion, gel or other structured system; “anhydrous” describes the absence of water rather than a separate physical state.

The final product form does not necessarily define the underlying formulation. For example, an adhesive may be a solution, emulsion, dispersion or structured polymer system before application and subsequently form an adhesive film on the skin. Similarly, an aerosol describes a method of product delivery rather than the fundamental formulation chemistry. The material contained within an aerosol package may itself be a solution, emulsion, suspension, powder or other formulated system that is dispensed using a compressed or liquefied propellant.

These classifications provide the physical-chemistry foundation for cosmetic formulation. Individual systems can then be defined according to their dispersed and continuous phases, rheology, interfacial properties, film formation, adhesion, stability and intended application.structured systems, or anhydrous systems, with considerable overlap between these classifications depending on composition and product structure.

Solutions are homogeneous systems in which one or more ingredients are dissolved at the molecular or ionic level within a continuous phase. Examples include aqueous toners, hydroalcoholic fragrances, some cleansers, and solutions of salts, acids, polymers, surfactants, or other soluble cosmetic ingredients.

Dispersions contain one phase distributed throughout another continuous phase. These include emulsions, in which one liquid is dispersed within another immiscible liquid, and suspensions, in which insoluble solid particles are dispersed within a liquid or semisolid continuous phase. Cosmetic examples include lotions and creams, pigmented foundations, sunscreens containing dispersed mineral particles, mascaras, and many color cosmetics.

Structured systems include gels, pastes, sticks, balms and other semisolid materials whose physical properties result from a three-dimensional network, high dispersed-phase concentration, crystallization, polymer association, particle interaction, or combinations of these mechanisms. A gel may therefore be based on an aqueous polymer network, an oil structured with a gelling agent, or another continuous phase. Wax-containing lipsticks, balms and sticks are examples of structured systems in which wax crystallization contributes to the mechanical properties of the formulation.

Anhydrous systems contain little or no intentionally added water. Examples include lipsticks, lip balms, oil-based serums, body oils, certain foundations, ointment-like cosmetic products, powders and some sticks. An anhydrous formulation may simultaneously be a solution, suspension, dispersion, gel or other structured system; “anhydrous” describes the absence of water rather than a separate physical state.

The final product form does not necessarily define the underlying formulation. For example, an adhesive may be a solution, emulsion, dispersion or structured polymer system before application and subsequently form an adhesive film on the skin. Similarly, an aerosol describes a method of product delivery rather than the fundamental formulation chemistry. The material contained within an aerosol package may itself be a solution, emulsion, suspension, powder or other formulated system that is dispensed using a compressed or liquefied propellant.

These classifications provide the physical-chemistry foundation for cosmetic formulation. Individual systems can then be defined according to their dispersed and continuous phases, rheology, interfacial properties, film formation, adhesion, stability and intended application.

Definitions