There’s a long list of ingredients that are used as chemical absorbers, so it’s easiest to simply look for products that are labelled ‘sensitive’ rather than search for specific ingredients. SPF make-up: does it really offer protection from the sun?

Dr Paul Banwell told us, "Some sunscreens use chemicals, such as oxybenzone, a known- allergen, and avobenzone to absorb UV rays, which can be detected in the body at harmful levels." However, there's no agreed definition of 'reef-safe', research is still ongoing as to the impact of these chemicals, and our tests found many mineral suncreams failed to protect as claimed – so take any claims with a pinch of salt. Kids' sun cream

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Cover up – wear sunglasses to protect your eyes and grab a hat if you need to keep your face out of the sun. You might also want to wear a T-shirt, which can help to cover up typically over-exposed areas such as shoulders. It takes longer for those with darker skin that rarely burns – it can take 25-40 minutes for the darkest skin type. We tested two popular sun creams in chlorinated water (to mimic a swimming pool) and salty water (to emulate the sea). We also added another scenario using fast-moving tap water to see what effect this had. Most of the time, the products weren't as effective in our more realistic conditions as they were in tap water.

It's common for sun creams to claim to be 'water resistant', but this doesn't mean that they're waterproof. We award Which? Best Buy status to products that we've independently reviewed that meet all our tough criteria: they must pass independent lab tests for UVA and UVB sun protection, and be easy and pleasant to apply. Consider the time of day – If you're spending time in the sun without wearing sun cream, you should only do so before 11am or after 3pm, as the middle of the day is when you're at the greatest risk of getting burnt.If you're using sun cream at the beach, apply plenty before swimming, and again when you leave the water. Reef-safe sun creams For environmentally conscious sun-seekers, this sun cream by Forever Living is the one to go for. It won the best sunscreen category in the Green Parent Beauty Awards in 2021, and it's vegan and cruelty-free. The inclusion of aloe vera and vitamin E is extra moisturising and soothes the skin, and the formula promises to be water resistant for 80 minutes. Remember, sun cream is just one part of staying safe in the sun and it's also really important to encourage kids (and adults) to:

The industry guideline for water-resistant sun creams allows the SPF of a product to drop by 50% after a total of 40 minutes in water. Water-resistance testing also takes place in what is essentially a bath – using tap water. Physical/mineral products reflect visible light as well as UV, which can make the formulations opaque and leave a white residue on the skin. Some formulations use nanoparticles of titanium dioxide and zinc oxide – the minerals responsible for the residue. Nanoparticles are smaller, and as they scatter visible light – rather than reflect it – the sun creams are transparent. How to use sun creamOxybenzoneis another ingredient to avoid as it is easily absorbed by the skin and enters the bloodstream, and it can disrupt your hormones as well as causing terrible harm to the environment. For any product to provide the SPF it claims, you need to apply 2mg per square cm – which means around a teaspoonful of product for your face. And, just as with sun cream, it needs to be reapplied regularly.