Patch Test and Its Importance in Dermatological Evaluation

July 16, 2025

zurko

Ensuring Cosmetic Safety:
Patch Test and Its Importance in Dermatological Evaluation

In an increasingly demanding and regulated cosmetic market, ensuring the safety of products before they reach the market is an unavoidable priority for any brand committed to the health of its consumers. At Zurko Research, we offer rigorous safety studies designed to validate the skin tolerance of cosmetic products under the highest scientific and ethical standards. Among these, the Patch Test stands out as an essential methodology in the dermatological evaluation of topical products.

What is a Patch Test?

The Patch Test, also known as the contact or patch test, is a clinical study aimed at assessing the skin tolerance of a cosmetic product under controlled conditions. It involves applying the product to the skin of healthy subjects, usually on the back, under a patch that remains adhered for a specific period—usually 48 hours—to observe any adverse reactions.

It is a crucial tool for detecting irritations or sensitizations before the product reaches the final consumer. Although it appears to be a simple test, its correct execution requires key technical decisions, such as the choice of occlusion type, which can significantly influence the results.

Occlusion and Semi-Occlusion: Why Does It Matter?

In a Patch Test, the type of patch used can be occlusive or semi-occlusive, and the choice between them depends on the type of product and its formulation. Each method has important implications for how the skin responds to the product.

Occlusive Patches:

Occlusive patches completely isolate the application area from air and moisture, creating a closed environment that enhances the product’s penetration into the skin. This can intensify skin reactions, especially in products with potentially irritating ingredients. They are useful for:

Products with low penetration potential (dense creams, pastes, ointments).

Studies in which a “maximum” evaluation of irritant potential is desired (very exaggerated conditions).

However, they can overestimate the skin’s response, and therefore may not always reflect the actual use of the product

Semi-Occlusive Patches:

Semi-occlusive patches allow some perspiration, making them more representative of typical cosmetic use. This type of application is preferred for:

Realistic use evaluations and prolonged tolerance testing.

Sensitive skin or studies involving specific populations (children, elderly adults).

Products with volatile ingredients, such as alcohol.

Strategic Choice: More Than a Technical Issue

At Zurko Research, the choice between occlusion and semi-occlusion is made on a personalized basis, considering the nature of the product, its usual application method, and the end consumer profile. Our approach combines scientific expertise with market understanding, ensuring reliable and applicable results.

Moreover, all our studies are designed in accordance with current European regulations (Regulation 1223/2009/EC) and are supervised by certified dermatologists, ensuring legal and scientific validity for use in the commercialization of cosmetic products.

Trust Zurko: Safety and Science in Every Formula

Conclusion

At Zurko Research, we have been working with leading cosmetic brands for over 15 years, helping them meet legal requirements and offer safe and effective products. Our commitment is clear: to ensure the safety of the final consumer and protect your brand’s reputation.

If you are looking for a reliable scientific partner to rigorously and professionally evaluate your products, you can count on Zurko.