How is a cosmetic product developed?

Cosmetic formulation involves designing a blend of ingredients intended to be applied to the skin or its appendages (such as hair, nails, or mucous membranes) for aesthetic purposes—such as cleansing, perfuming, protecting, or enhancing appearance.

Unlike medicines, cosmetics do not have therapeutic claims, but they must ensure both efficacy in their messaging and safety in their use. The development of a cosmetic product requires an initial R&D phase, during which the target audience, the commercial claim (such as anti-wrinkle or sun protection), and the galenic form (cream, gel, serum, etc.) are defined. In this stage, suitable active ingredients and their optimal concentrations are selected, and a prototype formula is designed.

Once the formulation proves effective in preliminary tests, it is mandatory to verify its safety before scaling up production. This safety report must include physicochemical, toxicological, and microbiological data on the product and its raw materials.

Main stages of the formulation process

The development of a cosmetic product is usually divided into several stages:

Product concept and design: the cosmetic’s function is defined (e.g., moisturizer, sunscreen, anti-aging), and market and consumer needs are analyzed. Based on this, the type of product is determined (such as a day cream or night serum), along with the expected results (like improved skin elasticity or a specific SPF level).
Ingredient selection: active ingredients (such as vitamins, antioxidants, hyaluronic or salicylic acid, peptides, etc.) and base components (solvents, emollients, oils, etc.) are selected to support the formula. The proportion of each ingredient is adjusted to maximize efficacy while minimizing irritation. During the R&D phase, pilot formulas are developed in the lab, where the texture, pH, and solubility of the ingredients are evaluated.
Formulation optimization: through preformulation testing, the cosmetic base (emulsifiers, gelling agents, humectants) is adjusted to achieve the desired consistency (creamy, fluid, gel-like). Auxiliary excipients such as thickeners, emulsifiers, humectants (glycerin, propylene glycol), gelling agents (cellulose, carbomers), preservatives, and fragrances are also added. Each additive must be selected considering its compatibility with the other ingredients.
Scaling up and pilot production: the formula is reproduced in larger batches (pre-production) using industrial mixing, homogenization, and filling equipment. Strict hygiene and Good Manufacturing Practices (GMP) are followed according to ISO 22716 standards. Any changes in ingredients or processes require revalidation of the formula.
Final testing and market launch: before launch, the product must undergo official testing for stability, packaging compatibility, efficacy, and safety. It can only be marketed if it meets all regulatory and quality criteria.

Cosmetic ingredients and their functions

Cosmetic components are grouped into several categories based on their function:

Active Ingredients: these are the functional ingredients that produce the desired cosmetic effect (e.g., antioxidants, moisturizers, or depigmenting agents). They act directly on the skin to improve its appearance (e.g., vitamins C and E, hyaluronic acid, retinoids, peptides).
Base substances or excipients: these are the solvents and carriers necessary for formulating the product. The most common is purified water (a safe universal solvent for the skin), though alcohols (ethanol, isopropanol), glycols (propylene glycol), or vegetable oils (jojoba, almond, olive) are also used. These excipients dissolve the active ingredients and ensure their even distribution throughout the product.
Emulsifiers: these are agents that stabilize mixtures of aqueous and oily phases. Examples include fatty alcohols (cetearyl alcohol), sorbitan esters (Span/Tween), polyethoxylated compounds (PEG), among others. They determine whether the emulsion is oil-in-water (O/W) or water-in-oil (W/O), influencing the final texture (light cream vs. thicker ointment).
Humectants and emollients: humectants and emollients are substances that provide hydration and softness. Humectants (such as glycerin, hyaluronic acid, propylene glycol) retain water in the epidermis, while emollients (mineral or vegetable oils, silicones like dimethicone) form a lipid film that softens the skin.
Thickeners and gelling agents: compounds (such as carbomers, celluloses, vegetable gums) that adjust the viscosity and texture of the cosmetic product. They allow for the creation of anything from light fluids to foaming gels or thick creams.
Preservatives: prevent microbial growth in the formulation. Since many cosmetics contain water and organic compounds, they are susceptible to contamination. Preservatives (such as parabens, phenoxyethanol, benzoic acid/sodium, sorbates) extend the shelf life by inhibiting bacteria and fungi. Their selection depends on the formula’s pH and current legislation, which prohibits or restricts certain substances (see regulations).
Cosmetic additives: these include colorants, fragrances, and conditioning agents (such as antioxidants, pH regulators). While not essential for the product’s primary function, they enhance the user experience (scent, appearance, and feel).

On the commercial label, all ingredients must be listed according to INCI nomenclature (standardized English names for chemicals and Latin names for plants). Additionally, ingredients are ordered by their concentration (from highest to lowest). This transparency allows consumers to identify formulas that are free from known allergens or undesired substances.

Legislation and regulation in Europe

In the European Union, cosmetics are regulated by Regulation (EC) No 1223/2009, which harmonizes the rules across all member states. Its key points include:

Definition of a cosmetic: as described in the regulation, a cosmetic product is “any substance or mixture intended to be applied to the external parts of the human body… for the purpose of… cleaning, perfuming, altering the appearance, protecting, maintaining in good condition, or correcting body odors.”
Safety and evaluation: each product must be safe for consumers under normal conditions of use. The manufacturer is responsible for evaluating the ingredients and demonstrating that they are not toxic, irritating, or carcinogenic at the intended concentrations. To do this, a Safety Report (part of the Product Information File, PIF) must be prepared before the product is marketed.
Responsible person (RP): the regulation requires having a physical or legal person established in the EU who assumes legal responsibility for the product. The RP must ensure compliance with all requirements, keep the Product Information File (PIF) up to date, and notify product details (before sale) in the European Cosmetics Notification Portal (CPNP).
Good manufacturing practices (GMP): cosmetic manufacturing must follow the GMP specified in ISO 22716 to ensure quality and hygiene. The product’s PIF must include a declaration of conformity with these practices. This control prevents contamination or variations between batches.
Ingredient lists: the regulation establishes lists of substances that are either prohibited or restricted (Annex II prohibits, Annexes III and IV restrict, and Annex VI approves UV filters). For example, only officially listed sunscreen filters can be used at the permitted levels. Additionally, if nanomaterials are used, they must be explicitly notified. Every formulation must document the origin and function of each ingredient, and the labeling must include the full INCI list of the product.
Labeling: it is mandatory to indicate on the packaging the identity of the Responsible Person (RP), batch number, expiration date or PAO (period after opening), usage precautions, net content, and the product’s function. Allergenic ingredients must be highlighted. In any case, the information must be provided at a minimum in the language of the country where the product is marketed.

This European regulation is complemented by national directives and periodic updates (e.g., recent modifications to UV filters or preservatives).

Cosmetic testing and validation

Before launching a product to the market, it is essential to subject it to quality assurance testing:

Stability testing: ensures that the formula maintains its properties (texture, pH, ingredient activity, and absence of separation) throughout its shelf life. Both accelerated and real-time studies are performed. Accelerated tests involve exposing the product to high temperatures, cold/heat cycles, and light exposure to simulate long-term conditions in a shorter time. Real-time testing involves storing the product under normal conditions for a specified period to observe any changes over time.
The chemical stability of a cosmetic is defined as “the ability to maintain its physical-chemical and microbiological properties within specified limits throughout its shelf life and during use.” This ensures that the expiration date is accurate, and the product does not lose its efficacy or degrade during storage.
Packaging compatibility testing: evaluates whether the packaging material (plastics, glass, aluminum, etc.) interacts with the formula or contaminates the product. This ensures that the packaging does not alter the chemical or physical properties of the cosmetic product and maintains its integrity throughout the product’s shelf life.
Efficacy testing: validates the cosmetic claims made by the product (e.g., anti-wrinkle, moisturizing, skin lightening). These tests can be conducted using instrumental studies or clinical trials with volunteers. The goal is to ensure that the product delivers the promised effects and provides scientific evidence to support its claims.
Safety testing: confirms the safety of the cosmetic formula when applied to the skin. These tests are crucial to ensure that the product does not cause adverse reactions such as irritation, allergic reactions, or other harmful effects. Safety testing can be carried out using both in vitro (lab-based) and in vivo (on human volunteers) methods, with strict ethical guidelines and consent protocols.

Meeting these tests guarantees that the cosmetic is stable, safe, and works as promised, as required by European legislation.

Characteristics of cosmetics

Formulators must adapt recipes to the specific characteristics of the product and user:

Skin type and phototype: dry, oily, sensitive, or acne-prone skin requires different formulations. For example, oily skin prefers oil-free textures or light gels, while dry skin needs creams rich in lipids and intensive humectants. Phototype (light or dark) is especially relevant in sunscreens, as the dose of UV filters and the SPF are adjusted according to each skin’s sensitivity to UV radiation.
Pharmaceutical form and route of administration: the presentation (cream, lotion, gel, serum, foam, oil, wipe) influences the choice of excipients. For example, a serum is usually fluid with a high concentration of water-soluble actives (hyaluronic acid, vitamins) in a light aqueous or hydroalcoholic vehicle. An anti-aging cream can be an oil-in-water emulsion with retinol and peptides; in these cases, the pH (~5–6) is controlled to stabilize the retinol and minimize irritation. Sunscreens are formulated with non-irritating emulsifiers and UV filters soluble in oil or water; they often include stabilizers (antioxidants) to prevent the degradation of filters and emulsifiers that maintain the texture after sun exposure.
Special additives: certain products include interactive ingredients. For example, a cream with vitamin C (ascorbic acid) requires secondary antioxidants (ferulate, vitamin E) and opaque packaging to prevent oxidation. Anti-wrinkle creams with retinol are formulated with encapsulations or retinoate forms to reduce irritation, and should be packaged in airless containers. Cosmetics for sensitive areas (eyes, genital areas) will use mild or hypoallergenic fragrances and very gentle surfactants to avoid reactions.

In every pharmaceutical (cosmetic) formulation, attention must be given to pH, viscosity, solubility of the actives, and organoleptic properties. The formulator’s challenge is to balance all these aspects: for example, a body highlighter product must be aesthetically pleasing (non-greasy texture, good absorption) while containing effective actives and remaining chemically stable.