Expired sunscreen is dangerous

Sunscreen is supposed to protect the skin. The UV filters contained in the lotion extend the skin’s own protection, so that you can stay in the sun longer. However, sunscreen is by no means permanent. It can expire and then even damage the body. What does science say about this?

If sunscreen has exceeded its shelf life, it can tip over and become rancid. This sometimes leads to irritation and rashes on the skin. The protective effect also decreases over time. Worse still, old sunscreen can develop a carcinogenic substance over time.

When expired sunscreen becomes harmful

Many sun protection products with organic chemical UV filters contain the inexpensive substance octocrylene. It plays an important role in the effectiveness of sunscreen, but is suspected of influencing hormone balance.

In addition, the substance is made from the possibly carcinogenic benzophenone. Since the substance can change the genetic material under UV light, i.e. also under sunlight, and promote the development of  cancer  , its content in sunscreen is considered to be very problematic. So far, the carcinogenic effect of bezophenone has only been confirmed in animal experiments, the World Health Organization rates the substance as “potentially carcinogenic”.

A study from France and the USA in 2021 suggested that benzophenone can not only be present as an impurity in the manufacture of sunscreen, but can also be a breakdown product of octocrylene.

The researchers examined 17 products. With the exception of one control product, all sunscreens contained octocrylene, according to the ingredients. All creams had benzophenone from the start. As part of an artificially induced aging process in sunscreen, the amount of the harmful substance doubled on average.

From this, the researchers concluded that the octocrylene must have been converted into benzophenone.

How long does sunscreen keep?

There are basically two characteristics by which you can read the shelf life of the sunscreen:

• Many sunscreen containers have a specific expiration date printed on them. However, this only applies to unopened packaging.
• In addition, the jar symbol is always printed on cosmetic products. It indicates how long you can safely use the opened product. The M after the number stands for months, so 6M means six months. It can be helpful to write on the tube with a marker when the sunscreen was first opened.

However, to be on the safe side, consumers should consistently dispose of the sunscreen at the end of the sun season. Even if it means that the pack has not been completely used up or if the manufacturer says it can be used longer.

How do you recognize expired sunscreen?

Neben dem Haltbarkeitsdatum gibt es noch weitere Möglichkeiten, abgelaufene und schlecht gewordene Sonnencreme zu erkennen. Aussehen und Geruch geben hier Hinweise: Falls die Sonnencreme schlecht riecht oder sich ihre Konsistenz oder Farbe verändert hat, sollten Sie die Creme vorsichtshalber entsorgen.

Naturkosmetik als Alternative

In zertifizierter Naturkosmetik darf kein Octocrylen enthalten sein. Die in diesen Sonnencremes enthaltenen UV-Filter sind mineralisch. Wer darüber hinaus auf Nanopartikel (Zinkoxid und Titanoxid) verzichten möchte, weil diese ebenfalls aufgrund ihrer möglicherweise Fittfeast sschädlichen Wirkung in die Kritik geraten sind, sollte auf der Liste der Inhaltstoffe auf den Zusatz “nano” achten.

However, the Federal Institute for Risk Assessment currently rates the application of products with nanoparticles as harmless. Only sun protection sprays, where the particles could be inhaled, should not be used.