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Updated: 3 Mar 2022

How we test sun creams

Find out how we uncover which sun creams you should avoid – and which are worthy of our Best Buy accolade.
Yvette Fletcher

Our sun cream tests show that you don't need to buy an expensive product to get one that looks and feels great on your skin and works as it should. We've tested affordable sun creams that work just as well as – or better than – products that are as much as nine times more expensive.

Every sun cream that passes through the Which? test lab is subject to British Standard tests to ensure it offers its claimed level of protection against ultraviolet radiation from the sun. Our reviews answer the crucial questions about sun creams:

  • Does its SPF match the claim on the label?
  • Will it protect skin from UVA? Does it meet the EU recommendation?
  • How does it look and feel on the skin?
  • Should I buy it?

Find a product that passed our rigorous SPF and UVA tests in our sun cream reviews.

Does the SPF match the claim on the label?

We use British Standard tests to check whether each sun cream has the SPF that is claimed.

The sun cream is applied to a small area on a volunteer’s back, then a lamp that shines UV light (simulating the rays of the sun) is placed on that area. We record when the skin turns red, and compare the smallest dose of UVB light required to turn skin red – both with and without the sun cream – to determine the cream’s SPF.

If an SPF30 product passes our SPF test but has an SPF greater than 50, it’s not eligible to be a Best Buy because it’s not meeting its SPF claim. It may seem positive to get more than you paid for, but that’s not the case when it comes to sun creams. A product with an SPF higher than it should have can lead to a false sense of security, because you may then expect all SPF30 products to offer the same higher level of protection.

Does it meet the EU recommendation for UVA protection?

The EU recommendation for UVA protection calls for sun creams to offer a UVA protection factor that is a third of their rated SPF in order to be considered effective protection against UVA. This means that an SPF30 product should have a UVA protection factor (UVAPF) of 10 or more.

Unlike SPF testing, the British Standard doesn't require UVA to be tested on human volunteers. Instead, we use a spectrophotometer (a machine that measures light) to measure the amount of UVA radiation absorbed by the sun cream.

How does the sun cream look and feel on the skin?

A panel of trialists test each sun cream, rating it on how easy it is to get out of the bottle, how it feels, looks and smells on the skin.

All of our Best Buy sun creams were rated four stars or above for application and passed our SPF and UVA tests. So, not only will they protect your skin, but they'll feel nice too.

Should I buy it?

All of the sun creams that pass our SPF and UVA tests can be relied on to protect you in the sun. We give our Best Buy recommendation to products that both pass these tests and receive four or five stars for application from our user panel.

Any product that fails our SPF and UVA tests is named a Don't Buy – we think these are the sun creams you should avoid.