By Dr Naomi Mackle, Dermatology Specialist and Medical Director, Adare Dermatology Clinics
Sunscreen is the single most proven anti-ageing and skin cancer prevention product you can use. Yet choosing one has never been more confusing. Chemical or mineral? Is zinc better than titanium? What is iron oxide doing in a tinted SPF? And are sunscreen chemicals safe?
As a skin cancer clinic, we get these questions every day. Here is what each type of filter does, who it suits, and how to choose the right sunscreen for your skin and lifestyle.
What are sunscreen filters?
Sunlight reaches the skin as three main types of radiation that matter for skin health:
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UVB, which causes sunburn and contributes directly to skin cancer. The SPF number measures UVB protection;
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UVA, which penetrates deeper, drives photoageing and pigmentation, contributes to skin cancer, and passes through glass;
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High-energy visible (HEV) light, the blue-violet part of visible light, which can worsen pigmentation disorders such as melasma.
Sunscreen filters fall into two broad groups.
Chemical (organic) filters absorb UV radiation and release it as a small amount of heat. They are usually lightweight, invisible on the skin and easy to formulate into elegant textures, sprays and mists.
Mineral (inorganic) filters are zinc oxide and titanium dioxide. They sit on the skin surface and protect it by absorbing and scattering UV radiation.
Zinc oxide
Zinc oxide gives broad protection across UVB and much of the UVA range. It is very gentle, non-irritating and well suited to sensitive and acne-prone skin.
Titanium dioxide
Titanium dioxide is excellent against UVB and shorter UVA wavelengths, but less effective against longer UVA, which is why it is usually paired with zinc oxide or chemical filters.
Iron oxide
Iron oxides are the pigments that give tinted sunscreens their colour. Standard UV filters do little to block visible light, but iron oxides do. This makes tinted formulas particularly valuable for people with melasma and other pigmentation problems.
What the evidence actually shows
The evidence for sunscreen is among the strongest in dermatology. A landmark Australian trial found that people who applied sunscreen daily showed significantly less skin ageing than those who used it only occasionally, and long-term follow-up showed a reduction in melanoma, roughly halving its incidence. Regular use also reduces squamous cell carcinoma.
For pigmentation, studies in melasma have shown that tinted sunscreens containing iron oxides, which block visible light as well as UV, give better results than UV-only sunscreens.
The evidence also has honest limitations. Most people apply far less sunscreen than is used in laboratory testing, so real-world protection is often lower than the number on the bottle. Protection also fades with sweat, swimming and towelling, which is why reapplication matters.
On safety, there has been a great deal of concern online about chemical filters. Studies have shown that some chemical filters can be absorbed into the bloodstream, and certain filters have been scrutinised for their possible effects on coral reefs. These concerns are taken seriously: filters are closely monitored and regulated, and concentration limits are reviewed. But absorption is not the same as harm, and there is no evidence that approved filters, used as directed, damage human health. What is certain is that skin cancer rates in Ireland and the UK are rising, skin cancer is the most common cancer in both countries, and its consequences can be devastating. Social media fears about “chemicals” should never put anyone off sunscreen.
Who each type suits, and who should be cautious
Mineral sunscreens suit acne-prone, sensitive and reactive skin. Their drawback is cosmetic: they nearly always leave some white cast. They give a lovely matte finish under make-up, but on their own they are less appealing, so they work best applied over a vitamin C (L-ascorbic acid) serum and moisturiser, and rubbed in well. For darker skin types, the white cast is rarely acceptable.
Chemical sunscreens are invisible and lightweight, making them the better choice for skin of colour and anyone who dislikes the feel of mineral formulas. Well-formulated modern products need not block pores.
Tinted sunscreens with iron oxide are ideal for melasma, post-inflammatory pigmentation and anyone prone to uneven skin tone.
Sprays and mists are ideal for scalps, bodies and children, but should be applied generously and in a well-ventilated space, avoiding inhalation. For children’s faces, spray into your hands first and apply. Babies under six months should be kept out of direct sun rather than relying on sunscreen.
Why REFORM uses these filters, and what we offer
At Adare Dermatology Clinics, skin cancer prevention is central to what we do, so REFORM’s sunscreen range was built around real patients’ needs rather than one formula for everyone.
REFORM Mineral SPF
Zinc oxide and titanium dioxide only, designed for acne-prone and sensitive skin. Expect a slight white cast; apply over serum and moisturiser and rub in well for a beautiful matte base under make-up.
REFORM SPF 50+
Very high protection made to the Australian standard, combining chemical and mineral filters. Beyond SPF 50+ UVB protection, it has a critical wavelength of 385 nm, meaning exceptionally strong UVA protection. This matters in Ireland, where UVA is present all year and passes through windows. Pilots, taxi, bus, lorry and ambulance drivers, and anyone who spends long hours in a vehicle, receive UVA through the glass every working day.
REFORM SPF 50+ Tinted
The same very high UVB and UVA protection, with added iron oxides to block high-energy visible light. This is our first choice for melasma and pigmentation disorders, which are particularly driven by UVA and visible light.
REFORM SPF Invisible Mist
A chemical-filter mist that is lightweight and suitable for all skin tones, including skin of colour. It was developed specifically for men and women with thinning hair or balding. Skin cancers of the scalp and ears are increasingly common, and a cream simply isn’t practical through hair. Many people sensibly wear a hat outdoors, but few wear one in a car, train or plane, where UVA exposure continues.
REFORM SPF 50 Body Mist
Very high protection made for ease of use on holidays and at the beach, where creams are messy, and for children who won’t sit still long enough for a cream.
How to use sunscreen safely and effectively
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Apply generously to all exposed areas: face, ears, neck, and backs of the hands.
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In the UK and Ireland, be especially vigilant from March to September, and whenever the UV index is 3 or above. Reapply every two hours outdoors and after swimming or sweating.
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In the morning, layer a vitamin C (L-ascorbic acid) serum under sunscreen for added antioxidant protection, and use a retinol at night.
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Don’t stop in winter. At ADC, we encourage patients to apply an SPF 30, or even SPF 15, once a day to exposed areas throughout the colder months.
I follow this myself. Even as winter approaches, I apply sunscreen every morning to my face, neck and the backs of my hands. I work indoors, so I don’t reapply, but with a significant family history of skin cancer, it is a habit I never skip.
The takeaway
There is no single “best” sunscreen, only the right one for your skin, your lifestyle and the one you will actually wear every day. Mineral filters suit acne-prone and sensitive skin, chemical filters offer invisible protection for all skin tones, and iron oxides add vital protection against visible light for pigmentation.
Whichever you choose, daily sunscreen remains the most important thing you can do for your skin. If you are concerned about a mole, pigmentation or sun damage, book a skin check at Adare Dermatology Clinics in Dublin, Limerick or London.
