Sun protection is a health issue worth taking seriously, and a complex one at that, not least because no product can offer 100 per cent safety from the harmful ultraviolet rays that can cause skin cancer.

Here at IndyBest, we research and rigorously test what’s on the shelves to bring you the cream of the crop, but we are not doctors with scientific knowledge and experience. To help guide us in a search we have taken seriously, we sought the advice of Dr Catherine Borysiewicz, a Cambridge and UCL-trained NHS consultant and a dermatologist at the award-winning Cadogan Clinic, a private hospital with a dedicated skin cancer department in London.

She explains that sunscreens have one of two “modes of action”: chemical sunscreens absorb ultraviolet radiation like a sponge, while mineral sunscreens containing titanium dioxide or zinc oxide reflect it back from the surface of the skin like a mirror.

“Mineral sunscreens with a high sun protection factor, UVA and UVB protection (the former penetrates the skin more deeply but the latter is more intense and the chief cause of sunburn) are as effective as chemical sunscreens, great for people with sensitive skin or inflammatory skin conditions such as eczema, and kinder to marine life,” she says. “They went out of fashion because they tended to leave a chalky white layer on the skin, but they are slowly becoming more popular again.”

This is because modern nanoparticle technology has enabled manufacturers to make the reflective agents smaller and easier to apply to the skin, meaning the sunscreens are less likely to leave unattractive chalky streaks.

What are the environmental issues at play?

Cosmetic concerns aside, rising awareness of the damage chemicals found in chemical sunscreens can do to delicate coral and marine life has led consumers to reconsider their choices. It is estimated that 25 per cent of the sunscreen ingredients we apply end up in the water.

Certain chemicals – including oxybenzone, octinoxate, octocrylene, octisalate, avobenzone and homosalate – have been identified as being particularly dangerous for eco-systems, making coral more susceptible to bleaching, deforming baby coral and degrading its resilience to climate change. Hawaii is taking these concerns so seriously that it has now put forward legislation to ban skincare companies from selling sunscreens containing oxybenzone and octinoxate on its islands. If the bill passes, it would be a world-first, and likely inspire other countries to follow suit.

Can these chemicals harm humans too?

These chemicals are also proven hormone disrupters that can seep through human and animal skin into other bodily tissue. Oxybenzone was recently found in 96 per cent of the population by the Center for Disease Control and Prevention in the US – an alarming statistic when you learn that this chemical can affect a man’s sperm count and contribute to the development of painful endometriosis in women.

Nanoparticles (ultrafine particles) smaller than 35 nanometres are also potentially damaging to humans – including those of zinc oxide and titanium dioxide found in mineral sunscreens – as they may enter the bloodstream and cause allergic reactions. However, sunscreen manufacturers are not legally obliged to reveal the size of the nanoparticles they use, making extra-conscious shopping tricky. Early studies have suggested that they would only be dangerous in large doses, but further global research is required.

Weighing both chemical and mineral sunscreens up based on what we know, we’d opt for the latter for both health and environmental reasons.

How can I best protect myself from the sun?

Dr Borysiewicz recommends choosing a sunscreen with a SPF of 50, which may seem over-cautious but is backed up by studies showing that on average, people apply less than half the amount of sunscreen required to provide the level of protection promised on the packaging. The most commonly missed spots are the neck, ears and back, so ask a friend to help you lotion up if needs be – and be sure to return the favour.

The sun is at its strongest from 11am to 2pm, so exposure within these hours should be limited, and remember that you can burn under cloud or shade. Regardless of a sunscreen’s water resistance claims, it is always best to reapply after swimming and especially after towel-drying. Top up your protection at least every couple of hours, too, no matter the SPF.

Dr Borysiewicz also recommends using UV protective fabric (UVF) for additional protection. “My routine for our two active young kids is to apply a layer of SPF 50, then dress them in high-necked, long-sleeved UV suits with protective large-brimmed sunhats to shade their delicate faces and chests,” she says, adding that her family tend to steer clear of the beach until after 5pm, when the sun is gentler.

Mineral sunscreens have the added benefit of being effective immediately after application, unlike chemical sunscreens which must be applied at least 15 minutes before sun exposure to give the skin time to absorb them. This makes the former a practical choice for children who will not stay still in their desperation to get outside!

How did we test these sunscreens?

To test these eco-friendly sunscreens, all free from the aforementioned chemicals, we packed them all into our suitcase and headed to Majorca for a fortnight of sun, sea and sand. They were all carefully tested on fair, freckly skin prone to burning and itchiness (high stakes, then…) and their water resistance was put on trial in both the swimming pool and the salty Mediterranean (both of which were freezing, you’re welcome).

The practicality of the packaging was also considered – no-one wants leaky oily sunscreen staining their new bikini – as was the ease of application and feel of the product on the skin. You may notice that none are sprays. This is because zinc oxide and titanium dioxide could be harmful to lungs if inhaled, so it’s safer to use lotion.

Here’s our pick of the best to help you do your bit for Planet Earth and return from your holiday glowing with health, not looking like a lobster.

You can trust our independent reviews. We may earn commission from some of the retailers, but we never allow this to influence selections, which are formed from real-world testing and expert advice. This revenue helps us to fund journalism across The Independent.

Aethic Sôvée Triple-Filter Ecocompatible Sunscreen SPF 40: £53 for 150ml

We raised our eyebrows at the price tag on this SPF 40 sunscreen too, until we learned that it was the only one in the world to have a patented eco-friendly formula. Aethic has rightly acknowledged that some organic and natural ingredients can be harmful to skin and marine life, while "biodegradable" means nothing if a product degrades and still causes damage. It claims to have had every ingredient individually scientifically-tested to ensure its safety for fish and coral. The London-based company then selected the best ones with the help of a leading marine scientist, blended them together and tested the final product again. It also makes donations to marine-positive charity The Going Blue Foundation, so it’s serious about the sea.

The other major benefit of this luxury vegan product is its triple-filter protection, which means it bats away more sun ray wavelengths than most sunscreens and does not show up on any skin tone. It shuns zinc oxide and titanium dioxide – the founder did not think enough research had gone into those minerals yet – and instead uses a naturally occurring compound found in seaweed, trademarked as Photamin, to protect your skin from the sun. Dubious? Understandable. To reassure you, this was proven by King’s College London scientists to absorb UVA and UVB rays as well as acting as an antioxidant. We then tested it in hot, direct sunlight over the course of five hours, and did not burn.

The creamy lotion squeezes out of its minimalist white tube easily and spreads quickly. It leaves a matte finish but we did notice a bit of dry white powder forming after a while, only noticeable close-up. It has a subtle fruity scent – from synthetic fragrance, but don’t panic, it’s been deemed safe – and we detected a hint of calming lavender. It comes in SPF 25 and SPF 15 – you pay less for a lower SPF but we think your skin, and our lovely oceans, are worth the money.

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Organii Sun Milk SPF 50: £23.95 for 125ml, Pravera

Organii’s range is a strong choice for parents wary of protecting their baby’s thinner, more delicate skin, as it’s entirely free from nasty synthetics, relying instead on vegetable oils and active plant essences. Certified organic by ICEA (a reliable Italian body), it’s fragrance-free – good news for those with easily-irritated skin – though it does have a subtle, not unpleasant, earthy smell.

The clue’s in the name with this sunscreen – it’s milky, though surprisingly thick to spread. It feels gentle on the skin and not at all sticky – it’s a bit greasy at first but rub it in thoroughly and it won’t leave a white layer. It comes in a white squeezy tube decorated with childlike drawings of suns. Unlike incognito’s offering, the contents come out too easily – the lotion is so runny that when you put the lid back on and stand it upright on it as intended, it runs out and collects inside, causing a messy spillage the next time you open it. Get around this by opening it over the area of skin you want to cover so as not to waste any – but we can’t deny it’s annoying.

The key ingredients here are zinc oxide and titanium dioxide, which reflect both UVA and UVB rays, with soothing benefits also found in organic argan, jojoba, linseed and marigold oils sourced from ethical manufacturers. The formula is vegan-friendly, too. We smothered ourselves in this before hitting our sunbed and only touched up once to be safe when the lunchtime sun came out in force. It says to reapply straight after swimming, which we think is sensible anyway, but we didn’t burn when drying off. If you have darker skin, it’s available in SPF 30, 20 and 15 too.

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Tropic Sun Balm SPF 50: £16 for 20ml, Tropic

This is the first sunscreen of its kind that we’ve tried. It’s not a full-body lotion, but a highly-concentrated touch-up balm in a sunshine-yellow mini pot ideal for popping in the pocket of a sundress if you’re having a bag-free day. Think of it as a saviour for those most exposed parts – the nose, forehead and the tops of your shoulder. It’s 100 per cent natural, with emollients derived from coconuts, so you can use it on your lips too without worrying about poisoning yourself. Zinc oxide is the chief warrior ingredient here, guarding against both UVA and UVB rays, while added rosemary leaf oil and vitamin E protect the skin from free radicals (unstable, reactive molecules in the air that can damage body cells). This SPF 50 balm is also a wise choice if you’ve already suffered mild sunburn as it contains tamanu oil which helps heal damaged skin.

We recommend it for sun lovers prone to break-outs as it was one of the least oily sunscreens we tested. The texture is similar to a heavy foundation but it smoothes on easily without leaving a sticky layer, feels lighter than expected on the skin and could be worn over makeup. It’s not the most hygienic as you need to smear your fingers over the compacted balm, and there is a slight whiff of clay, but it’s not off-putting and has no taste. We used it when exploring a Spanish town in the heat of the day and emerged both burn-free and envied by our family who had been lugging around big bottles.

Tropic whips up all its products in its Surrey "beauty kitchen" and it stamps a "best before" date onto everything – its sun balm is expected to stay fresh for six months, but we’ve used its products for much longer, so wouldn’t get hung up on that. It is certified by both The Vegan Society and Cruelty Free International.

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incognito Second Skin Suncream SPF 30: £24.99 for 150ml, incognito

Those of you jetting off on an exotic safari trip halfway around the world, listen up, because this is a sunscreen, mosquito repellent and moisturiser all in one. Firstly, we’ve fully researched its eco-credentials. Its UVA and UVB sun protection comes from zinc oxide and titanium dioxide and the repellent is PMD – a naturally occurring substance found in the lemon eucalyptus plant which is approved by the NHS and Public Health England and, unlike the slightly toxic Deet, does not harm the environment. This company goes several steps further, too – its black and green squeezy tube is made from renewable sugarcane plastic, its certified natural by Cosmos, it’s vegan and it donates 10 per cent of its profits to charities.

This sunscreen has been clinically tested to be 100 per cent effective against mosquitos for five hours – admittedly we were in Majorca, not Africa, making this difficult to test, but we spent a day by water with mozzies about and did not get bitten or burnt. Our lunch companions, however, we not fans of the strong clinical scent which we would describe as far more acrid than the "pleasant citrus fragrance" promised by the brand. To quote Dad: "I wouldn’t recommend wearing that to a dance".

Squeezing the tube to get enough cream out to cover our legs and arms proved a lot of effort and the white paste is thick and tough to spread. That being said, it’s not overly greasy or sticky and we liked being able to see where it was going to ensure we did not miss bits (the mozzies and hot sun rays always find them). We love the packing benefits of a three-in-one product, helping us stick to that 20kg luggage limit, but will be saving this one for more adventurous trips to malaria or dengue fever zones.

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Green People Facial Sun Cream SPF 30: £18 for 50ml, Green People

If it’s natural you’re after, this facial sunscreen is made with 78 per cent certified organic ingredients, chosen especially with sensitive skin in mind. It offers protection against both UVA and UVB rays, is scent-free to avoid irritating allergies and contains avocado and green tea extracts, both of which have anti-ageing properties that help to maintain skin elasticity. This lotion uses titanium dioxide boosted by naturally-occurring UV filters and can be worn under makeup as a protective primer it leaves no trace.

Unlike some other facial sunscreens, it did not cause our eyes to sting when smoothed into the surrounding area. It comes in a tube small enough to carry on you and the product comes out easily but slowly to help you minimise waste. It did not leave us shiny and sticky and saw us through a day on the beach with a top-up after a few hours – surprisingly effective for SPF 30 on our pale skin. We knew it worked as we forgot to put any on our nose and ended up resembling a certain red-nosed reindeer.

It does not claim to be water-resistant – instead it avoids mineral oil and silicone, key ingredients in waterproof sunscreens, because they clog pores and form a barrier on the skin that is akin to "wrapping it in cling film", causing intensifying prickly heat. Certified by the Vegan Society, Green People also donates 10 per cent of profits to the Marine Conservation Society.

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The Verdict: Eco-friendly sunscreens

Though the most expensive, we found a winner in Aethic’s Sôvée, which satisfied our demand for eco ingredients while proving faff-free to apply and keeping our skin safe from the sun. Organii offers a trustworthy, affordable range for children and those with fairer skin, though the runny consistency proved too much of a hassle to earn it top place.

IndyBest product reviews are unbiased, independent advice you can trust. On some occasions, we earn revenue if you click the links and buy the products, but we never allow this to bias our coverage. The reviews are compiled through a mix of expert opinion and real-world testing.