Cosmetic stability testing: how to guarantee the shelf life of your products?

Charline Radola
Aug 27
3 min read

The stability of a cosmetic product is a promise of quality and safety over time. A fragrance that evolves, a cream that loses its color, a color that fades... these are all signs that the formulation has not stood the test of time.

👉 Cosmetic stability tests help anticipate these risks and ensure that your products will remain safe and effective until their Best Before Date (BBD) or Period After Opening (PAO).

Why are stability tests essential in cosmetics?

A cosmetic product must not only be safe and compliant at the time it is placed on the market: it must remain so throughout its shelf life .

Cosmetic stability tests allow :

Check the physicochemical properties : texture, color, odor, pH, viscosity, SPF for sunscreens.
Guarantee safety of use : no microbial proliferation, no migration of undesirable substances from the container.
Justify the BBD or the PAO indicated by the “12M” or “24M” logo. for example.
Ensure long-term customer satisfaction .

💡 Without stability testing, it is impossible to validate the regulatory compliance of a cosmetic product.

The main methods of cosmetic stability testing

Methods vary depending on the nature of the product, its packaging and its conditions of use.

Accelerated aging

The product is subjected to high temperatures (40–45°C) for several weeks.

• ✅ Advantage: fast stability prediction.

• ⚠️ Limit: does not replace monitoring in real conditions.

Real-life testing

Observation of the product under normal conditions (room temperature, humidity, light).

• Allows you to validate the product’s performance over real-time use .

Stress tests (extreme tests)

Exposure to sudden temperature changes, freeze/thaw cycles or intense light.

• Objective: to verify the resistance of the cosmetic formulation to extreme conditions .

How to interpret the results and adjust a formulation?

Stability tests assess :

• Physical changes : phase shift, precipitation, variation in color or texture.

• Chemical changes : degradation of active ingredients, loss of effectiveness.

• Microbiological changes : contamination or microbial growth.

👉 If a problem is identified , the formulator can adjust:

• the oily phase (choice of more stable oils),

• emulsifiers (better cohesion),

• the conservative system (reinforced protection),

• packaging (glass, UV protection, anti-oxidation barrier).

Regulations and requirements in Europe

Cosmetic regulations require that the Cosmetic Product Safety Report (RSPC / CPSR) incorporates a stability assessment .

A stability test must demonstrate that:

• the product retains its initial properties ,

• it remains safe for human health ,

• the storage conditions and shelf life are justified .

📌 Without documented stability tests, it is impossible to validate a Product Information File (PIF) or to legally place a product on the market:

Practical tips for optimizing cosmetic stability

Anticipate from the formulation stage : choose stable ingredients, limit incompatibilities.
Testing under extreme conditions to identify weaknesses in particular cosmetic products.
Take care in choosing the packaging : container-product compatibility, UV protection, airtightness.
Working with a specialized laboratory : ensure rigorous monitoring and complete traceability.

💡 Investing in cosmetic stability testing means investing in quality, safety and customer loyalty .

In summary: stability testing, quality assurance

Cosmetic stability testing is not just a regulatory formality: it is the key to the quality and safety of your products.

By combining accelerated aging, real conditions and stress tests, it is possible to anticipate the weaknesses of a formula and optimize its lifespan .

At Galeniform , we support you in the realization of your stability and compatibility tests to ensure safe, compliant and sustainable products.