Sunscreens
Sunscreens can be useful for protecting our skin from the sun's rays. However, they will not protect us completely from sun damage on their own. This is why we recommend using sunscreens together with shade or clothing to avoiding getting caught out by sunburn.
You should never use sunscreen in order to spend longer in the sun.
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We recommend buying sunscreens with:
- a Sun Protection Factor (SPF) of at least 15 - the higher the factor of sunscreen the better
- “ broad-spectrum” sunscreens with a star rating of four stars or more
Also look out for brands that:
- have not gone past their expiry date - most sunscreens have a shelf life of 2-3 years
Try to apply sunscreen 15-30 minutes before going out in the sun. Reapply soon after to ensure that you get even coverage. Think of it as painting a wall - the first coat fills in any rough bits and the second gives an even layer.
Reapply every 2 hours or more frequently if washed, rubbed or sweated off. Even sunscreens that claim to be ‘waterproof’ should be reapplied after going in the water. We also recommend reapplying ‘once a day’ sunscreens, just in case you missed a bit.
Never use sunscreen to spend longer in the sun - this will put you at risk of sun damage that could lead to skin cancer.
Apply to clean, dry skin and rub in only lightly.
Do not store sunscreens in very hot places as extreme heat can ruin their protective chemicals.
The SPF is a measure of a sunscreen’s protection against the UVB rays that cause sunburn and skin cancer. The higher the factor the more protection you get from burning. But higher factors provide little in the way of extra protection.
For example, an SPF15 sunscreen filters out 93% of UVB radiation, while an SPF30 sunscreen filters out 96%. It is a common misconception that SPF30 offers double the protection of SPF15.
No sunscreen - no matter how high the factor - can offer 100 per cent protection. And it will only provide the right amount of protection if it is applied generously and regularly. On average, people put on about a quarter as much sunscreen as they should - at these levels, research has shown that even a sunscreen with SPF80 only provides an actual SPF of 3.
It is impossible to compensate for too thin a layer by increasing the factor you use. Therefore, it is crucial that you apply sunscreen generously and regularly.
Broad spectrum sunscreens block out UVA rays as well as UVB - these rays can also lead to skin cancer. In the UK we measure UVA protection with the 'star' system. Sunscreens can have anywhere from 0 to 5 stars. The number of stars is not an absolute measure and depends on how much UVB protection the sunscreen offers. For example, an SPF 25 with 3 stars may screen out more UVA overall than an SPF 10 with 4 stars.
- You need to use around two teaspoonfuls of sunscreen if you're just covering your head, arms and neck.
- You need around two tablespoonfuls if you're covering your entire body, while wearing a swimming costume.
- If you do not apply enough sunscreen, you are getting much less protection than is advertised on the bottle. And you cannot compensate for light applications by using higher factors.
Cancer Research UK does not endorse any specific brand of sunscreens. All sunscreens use the same method to determine how protective they are.
This means that brand and price are less important than things like the SPF and star ratings, which tell you how much protection they offer.
When it comes to sunscreens, the word “organic” does not have the same meaning that it does when used on food. It does not mean that a sunscreen is “natural” or contains fewer chemicals.
“Organic” is a technical term used in chemistry to describe molecules that contain carbon atoms. So the active ingredients in “organic sunscreens” contain carbon-based molecules, while the active ingredients in “inorganic sunscreens” do not - they are molecules like titanium dioxide.
Both types can help to prevent sunburn if used correctly - they just work in different ways.
- Organic sunscreens, also known as chemical sunscreens, work by absorbing ultraviolet rays from the sun.
- Inorganic sunscreens, also known as physical sunscreens or sunblocks, work by reflecting those rays.
Most available brands are now a mix of both types.
Some people find that inorganic sunscreens are harder to apply, and they end up putting less on. However, this is less of a problem for newer brands.
Inorganic sunscreens may be a better choice for children, because they are absorbed into the skin to a lesser extent and are less likely to trigger allergic reactions. Check for “titanium dioxide” or “zinc oxide” on the ingredients list.
However, both types of sunscreen work at protecting you from sunburn. The truth is that how you use sunscreen will have a far greater impact on reducing your risk of skin cancer than the type or brand that you pick.
Some sunscreens claim to provide effective protection after just one application. But we know that reapplying sunscreens regularly is very important because you are more likely to get even coverage and avoid missing bits that may then get burnt.
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