Saving lives with even better sunscreen | Science| In-depth reporting on science and technology | DW | 13.07.2015
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Saving lives with even better sunscreen

Even though modern-day sunscreens are excellent, there is still one problem: Many people simply don't like to apply the greasy stuff. Scientists have set out to work on the issue.

In many countries sunbathing just isn't fun anymore.

Especially in Australia and New Zealand, health organizations practice aggressive advertising to make people realize how dangerous sunlight is.

UV radiation not only gives you a sunburn, but also accelerates aging of the skin and increases the risk of skin cancer dramatically.

A good way to minimize sun damage is applying sunscreen. It contains complicated chemical molecules - UV filters - that absorb cancerous UV radiation.

Sunscreens that came on the market decades ago are quite different from the ones nowadays.

"In the old days, you could put a sunscreen on that would just protect against UVB radiation and that would protect you from getting sunburned," says John Staton. He heads Dermatest, his own sunscreen testing lab in Sydney. "You could sit and get your tan - what people thought was healthy. Now we know that tans are not healthy."

Tanning UVA radiation has a longer wavelength than UVB. It does not cause sunburn but penetrates the skin even further and causes long-term damages, including skin cancer. That's why modern sunscreens also contain molecules that absorb UVA rays.

The chemical structure of a UV filter molecule determines which kind of radiation it absorbs. UVA filters tend to be more complicated and bigger molecules than UVB filters.

Professor Michael Kimlin Queensland University of Technology Photo: Rainer Dückerhoff

Michael Kimlin: How effective a sunscreen is depends on its pleasantness

Today, sunscreens are a mixture of several UV filters that are effective at different wavelengths.

Making sunscreens more pleasant

Modern-day sunscreens "are great," says Michael Kimlin, who heads the AusSun Research Lab at Queensland University of Technology in Brisbane.

He showed that sunscreen stops the pigment cells in the skin from rapidly dividing. In the end, these cells cause skin cancer.

Other experts agree: As far as chemical protection goes, there are only minor things left that could be improved with modern sunscreen.

But the best sunscreen is useless when it's just sitting in the cabinet.

"Lots of studies have shown [..] that the best determinate of how effective a sunscreen is, is not so much the chemical sun-reducing quality of the sunscreen, because all of them have to meet certain criteria for government regulation, " Kimlin says. "The biggest criteria is how the sunscreen feels on your skin."

Many people just don't like to apply sunscreen. It is greasy, they say, and too heavy on the skin.

That's why a big part of today's research is aimed at making sunscreens more pleasant.

UV filters in bottles Photo: DW/Brigitte Osterath

UV filters are chemical substances that absorb UV radiation

Especially in Australia, this is the overall goal in sunscreen research. Here, skin cancer organizations have the vision that in the future applying sunscreen will become an everyday routine like brushing your teeth in the morning.

The formula counts

"The perfect sunscreen would feel light, had the required water resistancy, obviously had the right protection, but was as easy to apply as a skin moisturizer that felt good and smelt good", says Wladimir Budnik of Skin Health in Melbourne. The company develops and markets sunscreens for Cancer Council Australia.

But that is easier said than done.

Sunscreens are chemically different from skin moisturizers, mainly because they contain UV filters.

"We have to incorporate these UV filters into the cream," explains Uli Osterwalder, senior marketing manager for sun-care with the chemical company BASF in Germany. "And the amounts of UV filters are quite high: A sunscreen with sun protection factor 30 or 50 can contain 20 or even 30 percent UV filters - that is the problem."

Many UV filters are only soluble in oil - some of them are not soluble at all. But still, the components have to be mixed into one homogenous product.

Sunscreens contain many chemical substances apart from UV filters. Emulsifiers are needed for mixing oily and watery components. Emollients improve the sensorial behavior and solubilize UV filters. Thickeners make a product more viscous.

Mixing all substances together in a way that makes the product feel good is an art in itself.

The sunscreen that works best

So, which sunscreen should I buy? Kimlin's message to consumers is clear: "Use the one that feels best for you."

DW reporter Brigitte Osterath with Wladimir Budnik Photo: Rainer Dückerhoff

Wladimir Budnik: Choose the sunscreen type you like

The price of a product is not important, Kimlin adds. Cheap sunscreens will be just as good as expensive ones as far as UV protection goes - as long as the sun protection factor is high enough of course.

"At home we have four people at our house and there are four different bottles of sunscreen," he says. "Everyone likes something different, and that is fine."

To give consumers a big choice, there are many kinds of sunscreen applications on the supermarket shelves: lotion, spray, clear spray which is colourless instead of white, roll-ons and so on.

But experts warn that no sunscreen offers 100 percent protection. Even a sunscreen with sun protection factor 50 lets 2 percent of the sunlight onto the skin. It is a lot more if the sunscreen is not applied evenly and thick enough.

Wearing hats and sunglasses and staying in the shade whenever you can is just as important as sunscreen. "If you want to look beautiful forever, stay out of the sun, especially the Australian sun," Kimlin says, "It is quite bad!"

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