The topic is short and compact
The accelerated stability test over twelve weeks at 40 degrees Celsius predicts a shelf life of approximately 24 months.
All testing must be performed on the final formulation in the final primary packaging.
Without a safety report and a product information file, a cosmetic product cannot be placed on the market in the EU.
The European Cosmetics Regulation requires that a cosmetic product must be safe under normal or reasonably foreseeable conditions of use. This proof is not provided by experience, but by documented testing. Without this documentation, a product may not be placed on the market, regardless of how carefully it was developed.
The tests are not an isolated step at the end of development, but rather determine its course. Since all relevant tests must be carried out on the final formulation in the final packaging, the testing phase can only begin once both have been finalized. Anyone who leaves packaging decisions open automatically postpones the entire schedule.
Proof of safety through documented testing, not through empirical values.
Tests on the final combination of formulation and primary packaging.
Complete product information file as a prerequisite for placing on the market.
This sequence is the most common cause of launch delays. It can only be avoided by making the packaging decision early and bindingly.
The legal framework: Why pre-launch testing is non-negotiable
The European Cosmetics Regulation requires that a cosmetic product must be safe under normal or reasonably foreseeable conditions of use. This proof is not provided by experience, but by documented testing. Without this documentation, a product may not be placed on the market, regardless of how carefully it was developed.
The tests are not an isolated step at the end of development, but rather determine its course. Since all relevant tests must be carried out on the final formulation in the final packaging, the testing phase can only begin once both have been finalized. Anyone who leaves packaging decisions open automatically postpones the entire schedule.
Proof of safety through documented testing, not through empirical values.
Tests on the final combination of formulation and primary packaging.
Complete product information file as a prerequisite for placing on the market.
This sequence is the most common cause of launch delays. It can only be avoided by making the packaging decision early and bindingly.
Accelerated stability testing: Predicting shelf life in time-lapse
Accelerated stability testing simulates the aging of a product through elevated temperature. Storage for twelve weeks at 40 degrees Celsius is standard, supplemented by reference samples at room temperature and in the refrigerator. Based on the behavior under these conditions, a shelf life of approximately 24 months is concluded.
It is not only tested whether the product separates. Appearance, color, odor, pH value, viscosity and, if relevant, the content of sensitive active ingredients are recorded. An emulsion can remain visually perfect and still exhibit a significant pH drift or a loss of active ingredient, which invalidates the claim.
Twelve weeks at 40 degrees Celsius as the standard for shelf-life prediction.
Reference samples at room temperature and cooling for comparison.
Freeze-thaw cycles to represent transport and storage conditions.
Recording of pH value, viscosity, and active ingredient content, not just appearance.
Only when all parameters remain within the defined tolerances is the test considered passed. The tolerances should be established before starting so that the evaluation is not negotiated retrospectively.
Packaging compatibility: The interface between formulation and packaging material
The compatibility test examines the interaction between product and primary packaging in both directions. On the one hand, components of the packaging material can migrate into the formulation; on the other hand, formulation components can be absorbed by the packaging material. Both effects are particularly pronounced in the case of greasy products and longer storage times.
Particularly relevant in practice is the sorption of preservatives on plastics. If a part of the system is bound, the effective concentration in the product drops below the validated threshold, even though the formulation is unchanged. Microbiological safety is then no longer guaranteed, without this being externally recognizable.
Migration of packaging components into the formulation.
Sorption of preservatives and active ingredients by the packaging.
Mechanical testing of tightness, dispenser, and closure over the service life.
Testing for deformation, stress cracks, and label adhesion.
Therefore, the preservation challenge test must absolutely be carried out in the final packaging, and a control measurement of the preservative content is recommended at the end of the stability study.
Microbiological testing: Safety for water-based products
Every water-containing cosmetic product provides a potential growth environment for microorganisms. Microbiological testing covers two distinct aspects: the initial bioburden of the product and the ability of the formulation to control contamination during use.
The initial bioburden is tested by determining the total viable count and detecting the absence of specified pathogens. Stricter limits apply to products used in the eye area, on mucous membranes, or on children under three years of age than to other products.
Determination of the total viable count with product-category-dependent limits.
Detection of the absence of specified pathogens.
Stricter requirements for eye, mucous membrane, and children's products.
Batch-related release testing instead of random sampling.
Microbiological release is part of every production batch. A one-time test during the development stage does not replace ongoing control.
The preservative efficacy test according to ISO 11930
The preservative challenge test is the actual proof that the preservation system works. The formulation is specifically inoculated with defined microorganisms, and the rate and extent to which the microbial count decreases is measured over a specified period. The ISO 11930 standard defines test microorganisms, time points, and evaluation criteria.
It is important to distinguish between a passed and a barely passed test. A system that only barely meets the criteria offers no safety margin for batch fluctuations, sorption losses to the packaging, or stress during use. A significant fulfillment of the criteria is technically sensible.
Inoculation with defined test microorganisms according to a specified protocol.
Measurement of microbial reduction at defined time points.
Testing on the final formulation in the final packaging.
Sufficient safety margin instead of barely meeting the criteria.
If the test is not
The Safety Report: Part A and Part B
The safety report is the central document of the product information file and consists of two parts. Part A compiles the data: quantitative formulation, toxicological profiles of the raw materials, exposure assessment, stability and microbiological data, as well as packaging information. Part B contains the actual assessment and conclusion of the safety assessor.
Part B may only be prepared by an appropriately qualified person. The quality of Part B directly depends on the completeness of Part A. Missing test data leads either to more conservative assumptions that limit efficacy claims, or to the fact that the assessment cannot be completed.
Part A: complete data collection including all test results.
Part B: assessment and conclusion by a qualified person.
Exposure assessment depending on application type, quantity, and target group.
Retention of the product information file for ten years.
After completion of the safety report, the notification is made in the European portal. Only after this may the product be placed on the market.
The most common planning error is to schedule the testing phase as a short step at the very end. In fact, the twelve-week stability test determines the critical path. It can only begin once the formulation and packaging are final, and it cannot be shortened.
It is therefore realistic to expect about four to five months from the final release of the formulation and packaging until marketability: twelve weeks of stability testing, microbiological testing in parallel, followed by the safety report and notification. Production slots should only be booked bindingly after this.
Stability testing as a critical path with a minimum duration of twelve weeks.
Parallelization of microbiological tests wherever possible.
Binding packaging decision before the start of the testing phase.
Book the production slot only after the test results are available.
Anyone who adheres to this sequence avoids the typical situation in which a production batch has already been scheduled while release is still pending.
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FAQ
How long does an accelerated stability study take?
The standard is twelve weeks at 40 degrees Celsius, supplemented by reference samples at room temperature and under refrigeration. From this, a shelf life of approximately 24 months is extrapolated. This duration cannot be reasonably shortened, which is why the testing determines the critical path of the launch planning.
Why must testing be carried out in the final packaging?
Because formulation and packaging material influence each other. Components can migrate, and the packaging material can bind preservatives, causing the effective concentration to fall below the validated threshold. Changing the packaging after completion of the tests invalidates the results.
What does the preservative efficacy test according to ISO 11930 assess?
The formulation is specifically inoculated with defined test germs, and the rate and extent to which the germ count decreases over a specified period is measured. This proves that the preservation system actually controls contamination during use.
What does the safety report consist of?
From Part A with the complete data collection, including quantitative formulation, toxicological profiles, exposure assessment, as well as stability and microbiological data, and from Part B with the assessment and conclusion by a qualified person. The quality of Part B depends directly on the completeness of Part A.
How much time should be planned from the final formulation to the launch?
Realistically four to five months from the final approval of the formulation and packaging: twelve weeks of stability testing, parallel microbiological testing, followed by the safety report and notification in the European portal. Production slots should only be booked bindingly once the results are available.
Is a one-time microbiological test sufficient?
No. Testing during the development stage proves the fundamental suitability of the formulation, but does not replace ongoing monitoring. A microbiological release test is required for every production batch, not just random spot checks.
