How Does Sunscreen Work?

Sunscreen Explained

It’s a question that has mystified many people, standing in front of the sunscreen products in the supermarket and wondering which one to choose. Now, the experts at Neutrogena® are here to tell you exactly how sunscreen works – so you can always be assured of choosing the right products.
Sunscreen essentially provides a ‘screen’ which filters out most of the sun’s most harmful rays. UVA and UVB rays emitted by the sun can cause premature ageing of the skin, as well as sunburn and even skin cancer in some scenarios.

To filter out these rays, sunscreen contains a mixture of organic and inorganic ingredients, which either reflect, scatter or absorb the radiation, to negate its effects on the skin. Two of the most commonly used inorganic materials found in sunscreen are titanium dioxide and zinc oxide – these physically block UV rays from reaching the skin. These ingredients used to be bright white and very visible, but developments in the world of skincare and sun protection have meant that the particles can be broken down so they’re near-enough invisible, without compromising the protection they offer.

So what does the SPF factor mean?

The organic and inorganic compounds together provide a level of protection that we measure in factors – Sun Protection Factor (SPF), to be exact.

The SPF system works as follows. If it takes you fifteen minutes to burn in the sun, a sunscreen with an SPF of 30 would allow you to remain outside for 30 times that duration – or 7.5 hours. An SPF of 15 with a baseline of fifteen minutes would only allow you to remain outside for 225 minutes (or 2.75 hours).

Experts recommend reapplying sunscreen regardless of its SPF every two hours, to protect the skin properly and ensure it doesn’t succumb to premature ageing as a result of sun exposure.

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