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For the consumer it is very difficult to know what product to choose, since the photostability varies between different brands and the photostability is not marked on the bottle. To know which photoactive compound the sunscreen contains is not good enough. The stability also depends on factors like preservatives, oxygen radical scavengers, and base formulation. It is not reasonable that the ordinary consumer should have knowledge of this. If the product claims to give broadband protection, this protection should remain also after sun exposure. The fact that sunscreens are photounstable has been known for many years. Our study clearly shows that there are still many photounstable products on the market. When buying a sunscreen, the consumer should automatically receive a photostable product.

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Conclusion

The present study shows that several commercially available sunscreens are not photo stable. Degradation is clearly manifested in the absorption region in the UVA range after solar irradiation. In general, sunscreens with TiO2 particles seem to be more photostable, with Sunscreens 3 and 5 as exceptions. Special focus should be on the commonly used UVA absorber BMDBM. In three out of six sunscreens in our study this molecule was degraded during UV exposure. Stabilizers of BMDBM may work, but not under all conditions. There is a need for a standardized method to measure photostability and the photostability should be marked on the sunscreen product.

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