The three-star seal is awarded to short-term tests at the point of administration or to long-term investigations on the properties and condition of the skin or skin function in areas aside from the later point of administration. This includes, for example, the determination of improvement in the moisture content of the skin for a face cream that was tested on the forearm.
The three-star seal stands for a significantly more complex trial concept and even greater conclusiveness than that achieved with the simple patch test. The tests with these seals may include measuring physiological skin parameters such as the moisture content of the skin, skin roughness, skin elasticity, etc. This can also take place over long testing periods. Similarly, three-star seal investigations can provide statements on the allergic potential (in the case of repetitive epicutaneous tests, the testing period is longer than 4–6 weeks). An open epicutaneous test or a one-off administration test, both in the subsequent area of administration (e.g. face masks are testing for tolerance on the face), also receives a three-star seal as a result of the high conclusiveness and application-oriented test design. The trial design is thoroughly discussed with the client and specifically aligned to the product concerned.
Examples of a three-star seal test include:
- Long-term trial and determination of further physiological skin parameters (skin moisture content, skin elasticity, skin barriers, etc.)
- More intensive one-off testing of a product over and above the actual duration of the application and tests in the subsequent area of administration
- Repetitive epicutaneous test
For the exact identification of the 3-star-guarantee seal, the respective date of the award is indicated in the seal motif, and the Internet address www.3-star-guarantee.de leads to further information on the test design.