7 Types of Skincare Laboratory Tests that Need to Be Done Before Products Are Marketed

The skincare industry continues to evolve, bringing new products with increasingly diverse active ingredients, textures, formulations, and performance claims. From serums and toners to moisturizers, sunscreens, and exfoliating products, each formulation has its own characteristics and potential risks. Therefore, skincare laboratory tests play an important role in evaluating product quality, safety, and performance before products are marketed.

For this reason, a skincare formulation should not be evaluated solely based on its appearance, texture, or how comfortable it feels during application. Before a product reaches the market, manufacturers may need objective data related to its chemical characteristics, safety, microbiological quality, preservation system, and intended performance.

Skincare laboratory testing therefore plays an important role in product development and quality control. The U.S. FDA explains that manufacturers and distributors are responsible for ensuring that cosmetic products are safe when used according to their labeling or under customary conditions of use.

The agency also notes that there is no single predetermined list of laboratory tests that applies to every cosmetic product. Testing needs may vary according to the formulation, ingredients, intended use, and available safety information.

So, what laboratory tests should skincare manufacturers consider before placing a product on the market?

Table of Content:

• Chemical Compound Testing to Evaluate Product Composition
• Stability Testing to Evaluate Product Changes
• Microbiological Testing for Product Contamination
• Challenge Testing to Evaluate Preservative Effectiveness
• Toxicity Testing to Support Product Safety Evaluation
• Efficacy Testing to Support Product Performance Claims
• Molecular Biology for Specific Biological Targets

Chemical Compound Testing to Evaluate Product Composition

Chemical analysis is one of the important areas of skincare laboratory testing. Modern skincare formulations can contain a wide variety of active ingredients, including niacinamide, salicylic acid, alpha arbutin, retinol, vitamin C derivatives, peptides, and many other compounds.

Although an ingredient may be included in a formulation at a specified concentration, manufacturers may still require skincare laboratory tests to obtain objective analytical information about the material or finished product.

Depending on the objective, laboratory analysis may be designed to evaluate:

• ingredient identity;
• active ingredient concentration;
• purity;
• specific chemical characteristics;
• impurities or unwanted compounds; or
• formulation consistency.

For example, if a serum is formulated with a particular concentration of an active ingredient, chemical analysis may help determine whether the measured concentration meets the manufacturer's established specifications. The analytical method must be selected according to the chemical properties of the compound being tested and the complexity of the formulation.

Through Chemical Compound Testing as part of skincare laboratory tests, manufacturers can obtain analytical data to support raw material evaluation, formulation development, and finished-product quality control.

Stability Testing to Evaluate Product Changes

A skincare product should not only have acceptable characteristics immediately after manufacturing. The formulation should also maintain its intended quality during storage, making skincare laboratory tests important for evaluating product stability and quality over time.

Temperature, light exposure, oxygen, humidity, packaging, and interactions between ingredients can affect the characteristics of a cosmetic formulation. Through skincare laboratory tests, manufacturers can evaluate how these factors influence product stability, quality, and formulation consistency over time.

Changes may appear as:

• discoloration;
• odor changes;
• phase separation;
• precipitation;
• viscosity changes;
• pH changes; or
• degradation of certain active ingredients.

Some active ingredients are particularly sensitive to light, heat, or oxidation, which may affect their characteristics or concentration during storage. Therefore, skincare laboratory tests are important for evaluating these potential changes and supporting product stability and quality assessment.

Stability evaluation therefore helps manufacturers understand how a formulation behaves under predetermined storage conditions. The information obtained may support decisions related to formulation optimization, packaging selection, storage recommendations, and shelf-life evaluation.

Microbiological Testing for Product Contamination

Microbiological quality is another important consideration, particularly for water-based skincare products. Through skincare laboratory tests, manufacturers can evaluate potential microbial contamination originating from raw materials, water, manufacturing equipment, environmental exposure, packaging, storage, transportation, or consumer handling.

The FDA identifies contaminated ingredients or water, poor manufacturing conditions, ineffective preservation, unsuitable packaging, and storage conditions as potential sources of microbial contamination in cosmetics. Although cosmetics are not generally required to be sterile, skincare laboratory tests can help evaluate microbial quality and ensure that harmful microorganisms and microbial levels are appropriately controlled.

Microbiological testing can therefore be used to evaluate microbial populations and the presence of specified organisms. The FDA's Bacteriological Analytical Manual highlights microorganisms such as Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans as organisms of particular concern when assessing cosmetic microbiological quality.

However, evaluating the microbial condition of a newly manufactured product through skincare laboratory tests addresses only one part of the issue. Manufacturers may also need to determine whether the formulation can resist microbial contamination during storage and consumer use.

Challenge Testing to Evaluate Preservative Effectiveness

Many water-containing skincare formulations use a preservative system to help control microbial growth. However, simply adding a preservative does not automatically demonstrate adequate protection, making skincare laboratory tests important for evaluating the effectiveness of the preservative system in the finished formulation.

A Challenge Test, also known as a Preservative Efficacy Test, is used to evaluate how the product's preservation system performs when the formulation is exposed to selected microorganisms under controlled test conditions. ISO 11930:2019 describes procedures for evaluating the overall antimicrobial protection of cosmetic products and includes a preservation efficacy test as a reference approach for relevant cosmetic formulations.

Preservative performance may be influenced by numerous factors, including:

• formulation pH;
• emulsion structure;
• preservative concentration;
• surfactants;
• active ingredients;
• water activity;
• packaging; and
• interactions among formulation components.

Scientific literature on challenge testing also emphasizes that preservative effectiveness can be difficult to predict from formulation composition alone, particularly in complex cosmetic systems. Therefore, skincare laboratory tests such as Challenge Testing can provide more relevant information about preservative effectiveness than simply confirming that a preservative appears on an ingredient list.

Toxicity Testing to Support Product Safety Evaluation

Safety is a central consideration in skincare product development. An individual cosmetic ingredient may already have available safety information, but the formulation, concentration, exposure route, intended use, and target population must also be considered when evaluating a finished product.

The FDA notes that toxicological or other skincare laboratory tests may be needed to address gaps in available safety information for cosmetic ingredients or finished products.

The testing strategy should be based on product-specific factors such as:

• ingredient composition;
• active ingredient concentration;
• expected exposure;
• frequency of application;
• intended application area;
• target user population; and
• potential hazards associated with the formulation.

For example, a product intended for the eye area may require a different risk assessment approach from a body moisturizer. Similarly, formulations containing certain active ingredients may require closer evaluation depending on their concentration and expected exposure.

Toxicity Testing, as part of skincare laboratory tests, can therefore provide valuable data to support a broader product safety assessment rather than simply functioning as a final pass-or-fail requirement.

Efficacy Testing to Support Product Performance Claims

The modern skincare market is highly claim-driven. Products may claim to moisturize, improve skin appearance, protect against UV radiation, support specific cosmetic benefits, or provide other functions.

However, the presence of a well-known active ingredient does not automatically prove the performance of the finished product. When a product communicates a specific functional claim, an appropriate efficacy assessment can provide objective data regarding its performance.

Sunscreen is a clear example. Products designed to protect the skin against ultraviolet radiation require appropriate testing to evaluate their protective performance. SPF Testing, for example, can be used as part of Efficacy Testing to assess sunscreen or sunblock performance according to the selected methodology.

The same principle applies to other cosmetic products: the parameter being measured should match the intended claim. It is important to distinguish ingredient presence from finished-product efficacy.

A formulation may contain an ingredient associated with a particular cosmetic function, but the final performance can still depend on concentration, stability, formulation design, delivery to the application site, and interactions with other ingredients. Efficacy Testing can therefore provide more objective support for evaluating product claims.

Molecular Biology for Specific Biological Targets

Molecular Biology is not automatically required for every skincare product. However, DNA- or RNA-based methods may be relevant when testing objectives involve detecting or identifying specific biological materials.

Techniques such as PCR and qPCR analyze specific genetic targets. Their purpose therefore differs substantially from conventional chemical compound analysis.

Within cosmetics and related products, Molecular Biology may be considered when manufacturers need to identify certain biological sources, detect targeted genetic material, or answer questions that cannot be addressed solely through chemical analysis. The key is to select testing according to the question being asked.

For example: If the objective is to measure the concentration of retinol or alpha arbutin, Chemical Compound Testing is generally more relevant. If the objective is to evaluate potential safety concerns, Toxicity Testing may be appropriate.

If the manufacturer wants to evaluate whether the product performs a claimed function, Efficacy Testing may be considered. If the target of analysis is specific DNA or genetic material, Molecular Biology may be the more suitable approach.

Does Every Skincare Product Need the Same Tests?

No. One of the most important principles in cosmetic testing is that the testing program should match the product. There is no universal testing package that automatically applies to all skincare formulations.

The appropriate testing strategy should consider:

• formulation type;
• ingredients;
• water content;
• preservative system;
• packaging;
• intended use;
• target population;
• application area;
• product claims; and
• identified risks.

The FDA similarly explains that it does not maintain a single required list of tests for every cosmetic product. Manufacturers remain responsible for determining what information is necessary to support product safety.

For example, a water-based moisturizer may carry a different microbiological risk from an anhydrous formulation. A sunscreen requires different efficacy data from an ordinary toner. A formula containing a sensitive active ingredient may require specific chemical and stability analysis.

A risk-based testing strategy can therefore provide more useful information than conducting multiple tests without clearly defined objectives.

Laboratory Testing Should Begin During Product Development

Another important consideration is timing. Manufacturers should not necessarily wait until a product is ready for launch before considering laboratory testing.

Testing can provide greater value when incorporated during formulation development. If laboratory results reveal an issue, developers still have an opportunity to:

• reformulate the product;
• adjust ingredient concentrations;
• optimize the preservative system;
• modify packaging;
• improve manufacturing controls; or
• reassess product claims.

The FDA's cosmetics GMP guidance also includes laboratory controls covering raw materials, in-process samples, and finished products for physical and chemical characteristics, microbial contamination, and unwanted chemical contaminants. Therefore, laboratory testing should not only be viewed as a final checkpoint. It can also function as a tool for product development and quality improvement.

Support Your Skincare Product with Laboratory Testing Data

Don't rely solely on formulation concepts and product claims. Support your skincare product with relevant laboratory testing data before it reaches the market!

IML Testing & Research provides Efficacy Testing, Toxicity Testing, Molecular Biology, and Chemical Compound Testing services to help companies evaluate different product characteristics according to their testing objectives.

Developing a serum, toner, moisturizer, sunscreen, or other skincare product? Contact IML Testing & Research today and discuss your skincare laboratory testing requirements with our team!

Author & Editor: Lina

References

International Organization for Standardization. (2019). ISO 11930:2019 Cosmetics — Microbiology — Evaluation of the antimicrobial protection of a cosmetic product.

U.S. Food and Drug Administration. Product Testing of Cosmetics. FDA.

U.S. Food and Drug Administration. Microbiological Safety and Cosmetics. FDA.

U.S. Food and Drug Administration. (2024). Bacteriological Analytical Manual, Chapter 23: Methods for Cosmetics.

U.S. Food and Drug Administration. Good Manufacturing Practice (GMP) Guidelines/Inspection Checklist for Cosmetics.

Russell, A. D. (2003). Challenge testing: principles and practice. International Journal of Cosmetic Science, 25(3), 147–153.

Abdelaziz, A. A. et al. (2024). Microbiological Quality Assessment of Skin and Body Care Cosmetics by Using Challenge Test. Saudi Journal of Biological Sciences.

Orth, D. S. et al. Adequacy of cosmetic preservation: chemical analysis, microbial challenge and in-use testing. International Journal of Cosmetic Science.