Physical or mineral sun creams create a barrier on the skin that acts like a mirror, reflecting and scattering the UV light.

For reasons of hygiene and safety, personal grooming products, cosmetics or items of intimate clothing cannot be returned. 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." Sun cream provides protection from sunlight using UV filters. These are classified into two types: chemical and physical – also known as mineral sun cream.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. There are a number of criteria to consider when choosing the best sun cream for your skin, and these include sun protection factor (SPF), UV protection, water resistance and sun cream type - as well as ease of application and how it feels on your skin. The NHS recommends using a minimum SPF of 30 to protect against UVB. However, Dr Paul told us that he recommends using SPF 50, as well as staying in the shade, wearing protective clothing and staying out of midday sun. He added, "Other ingredients that may cause reactions include benzophenones, cinnamates and dibenzoylmethane.

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? Find out what you need to know about 'once a day' sun creams, water-resistant sun creams, sensitive sun screen and the best kids' sun cream too. When choosing sun cream for your child, look for a short ingredients list and the terms 'fragrance free' and 'hypoallergenic'. The WHO recommends 35ml of sun cream (seven teaspoons' worth) to cover an adult, so use around a quarter to a half of this depending on the size of your child. He added, "Most people apply sunscreen too thinly and that means protection is reduced. An adult should be applying around six to eight teaspoons to cover their body.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 NHS recommends reapplying sun cream every two hours, as the sun can dry it off your skin. They add that when applying sun cream for the first time that day you should do this twice: 30 minutes before going out and again just before leaving.

Dr Paul Banwell, who runs The Banwell Clinic and is the previous head and founder of The Melanoma and Skin Cancer Unit (MASCU) in East Grinstead, agrees. He told us: "I cannot emphasise enough the importance of selecting a broad spectrum sunscreen, which will protect against UVB and UVA rays. UVB rays cause redness and sunburn as well as skin cancer, while UVA rays can also cause cancer as well as ageing of the skin. Newer sunscreens have infrared (IR) protection too and should be considered." Sun creams to avoid: The warning signs to look out for If your face or certain areas of skin are going to be super exposed to the sun for long periods then you should not only rely on suncream but wear a brimmed hat and sunglasses and cover the upper body with a rash vest or long-sleeved light cotton top. Sun cream alone cannot completely protect the skin from direct UV rays over a longer period of time." How often should I reapply sun cream? Mineral sunscreens in particular often promote their environmental credentials, the most common being that they’re ‘reef-safe’ or 'ocean-friendly'. For more details on the importance of vitamin D and where to buy supplements, see our in-depth vitamin D guide . Other ways to stay safe in the sunIt takes longer for those with darker skin that rarely burns – it can take 25-40 minutes for the darkest skin type.

Dermatologist and cosmetologistDr Eva Melegh told us: "If you are prone to sensitive skin or you are applying suncream to children’s skin then you it’s best to opt for mineral sun creams as opposed to chemical filter ones, as they have less chance of causing a skin reaction to sensitive skin. If you have sensitive skin a very helpful product is Kalme Undercoatwhich is designed to wear under sun creams to reduce the risk of skin reactions." 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. You can buy sun cream in pharmacies, supermarkets and discount stores, with some of our tested options coming from Asda, Boots, Garnier, Nivea and Wilko. Eat well, live better and stay healthy - sign up for our free monthly Food & Health newsletter for the latest insights delivered straight to your inbox Oxybenzoneis 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.

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UV protection: Sun creams receive a UV star rating out of 5, which measures how well a sunscreen protects against the sun’s UVA rays. Broad-spectrum sun creams protect against both UVA and UVB rays. 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. 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. From April to September, when the UV Index is generally higher. It takes 10 to 15 minutes of sun exposure each day for those with fair-to-olive skin to get enough vitamin D.