How to choose a facial sunscreen: the anti-ageing product with the most evidence and the mistake that halves it

If you had to keep one product out of the whole washbag, it would be this one. Sunscreen is the only cosmetic with a long-term randomised trial demonstrating that it prevents skin ageing, not just sunburn: in a study of 903 adults followed for four and a half years, the group using it daily showed 24% less skin ageing than the group using it when they felt like it.

And there is one detail that decides a good part of the result: the number on the pack is measured applying an amount almost nobody puts on. This page explains what to look for on the label, how much is really needed and what distinguishes a good facial sunscreen from one abandoned within a week.

It is part of the dermocosmetics guide, where the framework of what a cosmetic can and cannot do is set out.

What the trial demonstrated

It is worth dwelling on, because it is the whole argument.

It was carried out in Nambour, Australia, and published in Annals of Internal Medicine. 903 adults under 55 were randomly assigned to four groups, combining two variables: daily sunscreen use against discretionary use (whatever each person decided), and a beta-carotene supplement against placebo. Follow-up lasted four and a half years.

The result:

• The daily-use group showed 24% less skin ageing than the discretionary-use group (odds ratio 0.76).
• Beta-carotene had no effect at all on skin ageing.

Two things make this study weigh so heavily:

1. It is randomised. It does not compare people who look after themselves with people who do not — who differ in many other ways — but two groups assigned at random.
2. It measured ageing, not sunburn. That is what interests anyone buying anti-ageing skincare, and it is exactly what has almost never been measured in a trial.

🔑 The contrast is the useful information: no serum, no cream and none of the actives sold at a high price has anything remotely like this behind it. The cheapest product on the shelf does.

How to read the label

The number (SPF)

It measures protection against UVB radiation, the main cause of sunburn. It is a number obtained in a standardised test, and here is the critical point: that test applies 2 mg/cm² of product. The European Recommendation explains it and gives the practical reference: 2 mg/cm² is equivalent to about six teaspoons of lotion — some 36 grams — for the whole body of an average-sized adult.

The Recommendation also classifies products into four categories — low, medium, high and very high protection — and sets out which number corresponds to each. This is the official table, which is almost never published in full:

Three things can be read there and on no pack:

• 🔑 A “50” and a “50+” are not the same. The first corresponds to a measured value between 50 and 59.9; the second, to 60 or more. It is the only way of indicating that the top of the scale has been passed.
• 🔑 A “30” may have measured almost 50. The high category runs from 30 to 49.9, and the number printed is the bottom of the band. The label always rounds down.
• ⚠️ The list of numbers is not a free choice. The Recommendation expressly restricts the multiplicity of figures so that products can be compared: 6, 10, 15, 20, 25, 30, 50 and 50+. A pack with a number outside that list falls outside the European recommendation.

In addition, the category must appear on the label at least as prominently as the number, and for any of them the same UVA protection is required — one third of the SPF — and the same minimum critical wavelength, 370 nm.

The UVA symbol

UVA radiation penetrates more deeply and is implicated in photoageing. Its protection does not appear as a number but as the logo of the letters UVA inside a circle, which indicates that the product meets the European criterion: UVA protection is at least one third of the stated protection factor.

That is: on an SPF 50 with that mark, the UVA protection is equivalent to at least 16-17. If what you are after is photoageing and pigmentation, that circle matters as much as the big number.

What the label cannot say

European rules are explicit, and it is worth quoting them because they dismantle half the sector’s advertising. Claims should not be made implying:

• 100% protection against UV radiation — such as “sunblocker” or “total protection”;
• that reapplication is never necessary — such as “all-day prevention”.

And the opposite statement must appear: “To maintain protection, reapply the product frequently, especially after perspiring, swimming or towelling”.

🚫 If you see “total sunblock” on a pack, you are not looking at a better product: you are looking at a claim the rules say should not be made.

The mistake that takes half of it away: the amount

Here is the difference between the SPF you buy and the one you put on.

What the real-world application studies say:

• In a survey of more than 9,000 people, facial application averaged 3.00 mg/cm² — with a median of 1.78 — and body application 1.52 mg/cm², with a median of 1.35. In that same paper’s historical review, 36 of 38 published values were below the reference 2 mg/cm².
• In another application study, the geometric means were 1.1 mg/cm² with lotion, 1.6 with spray and 0.35 with stick.
• In children, the median fell to 0.48 mg/cm².

And the nuance that changes the conclusion: the relationship between amount and protection is not linear at high factors. At low SPFs protection follows the dose roughly proportionally, but at high ones the relationship is exponential, so that the consumer gets considerably less protection than the number suggests when they under-apply.

🔑 The practical conclusion is not to be alarmed: it is to put on more. Choosing a high SPF and applying half of what is needed is exactly the scenario in which most is lost. Putting a generous amount on the face, ears, neck and backs of the hands, and repeating through the day, does more than raising the number on the pack.

Mineral or organic filters

It is the most frequent question and the short answer is that both protect.

Mineral filters (zinc oxide, titanium dioxide). They work mainly by reflecting and scattering radiation. They tend to be better tolerated on reactive skin and are the most usual choice for sensitive skin and for children. Their classic drawback is the whitish cast, greater the darker the skin tone — a real reason for giving up on them, not a frivolous complaint. Tinted versions exist that solve it.

Organic filters (sometimes called “chemical”). They absorb radiation. They allow lighter textures and more cosmetic finishes, which in practice greatly improves the chances of the product being used daily.

How to decide, without ideology:

• Reactive skin, rosacea or after a procedure: mineral is usually the more comfortable bet.
• Oily or acne-prone skin: fluid textures, gel-creams or matt finishes.
• Medium or dark skin tone: consider tinted minerals, or organic filters, to avoid the cast.
• Daily use under make-up: texture comes first, because sticking with it comes first.

⚠️ And a warning about the framework: every sun filter authorised in the European Union has been assessed and listed in the corresponding annex of the Cosmetics Regulation. “Mineral” is not a synonym for “safer”, any more than “natural” is. It is a choice about tolerance and finish.

What SPF does not cover: visible light

There is a part of the spectrum that neither the SPF number nor the UVA symbol measures, and which in one specific case changes the outcome of treatment: visible light, the light you can see. On medium and high phototypes, visible light induces pigmentation changes comparable to those produced by ultraviolet. A transparent sunscreen, however high its factor, does not filter it.

This was measured in a randomised, double-blind trial with 68 patients with melasma, all also treated with 4% hydroquinone. At eight weeks, the group using a sunscreen that incorporated iron oxide — a pigment that absorbs visible light — obtained an improvement 15% greater on the MASI index and 28% greater on colorimetry than the group with a UV-only sunscreen, both at factor 50 or above.

🔑 How to recognise it on the label: iron oxides are declared in the ingredients list as CI 77491, CI 77492 and CI 77499. In practice, they are what gives the colour: tinted versions carry more pigment and therefore more protection against visible light. What many people choose for cosmetic reasons — a tinted sunscreen, so as not to look pale — turns out to be, in this particular case, the technically better choice.

⚠️ When it really matters: if there is melasma or post-inflammatory hyperpigmentation, and in medium and dark phototypes. To prevent sunburn and photoageing in general, UVA and UVB remain what counts, and this nuance does not change the basic recommendation. The full approach to melasma is in why melasma comes back and what really works.

What we dispense, and why precisely that

Of the sunscreens we stock at the clinic, the Mineral Fluid SPF 50 by Allskin Med is the one that answers to this section: the brand declares 100% mineral filters — titanium dioxide and zinc oxide — and tone-evening micropigments, along with Polypodium leucotomos extract and vitamins C and E. And it has two tinted versions that carry more pigment: beige and bronze.

🔑 And there is the detail almost nobody connects. Many people choose the tinted version for an aesthetic reason — not to go about with a white cast — and it turns out that on skin with pigmentation it is also the technically better choice, because the pigment is precisely what absorbs visible light. The cosmetic reason and the clinical reason point, for once, to the same product.

⚠️ Said with the precision it deserves: what the brand declares is “micropigments”, and iron oxides are identified in the pack’s ingredients list as CI 77491, CI 77492 and CI 77499. If this matters to you, check it on the pack before buying — that goes for ours and for any other. And the study supporting the benefit was done in patients with melasma and on treatment with hydroquinone: it is not an argument for general sun protection.

When more care than usual is needed

• If you use retinol or acids. They increase sensitivity to radiation, and sun damage is exactly what you are trying to reverse. It is in how to start with retinol.
• If you have pigmentation. No depigmenting agent works on skin that keeps getting sun: it is the precondition, not an extra. It is in creams for facial pigmentation and, for melasma, in why melasma comes back.
• After a laser or pulsed light. The specific care and timings belong to recovery from CO₂ laser and to the pages for each technology.
• On a recent scar. It has a protocol of its own and this is not it: it is in the scar protocol after surgery.
• If you take photosensitising medicines. That is a question for your doctor or your pharmacist, not for a label.

The sunscreens in the catalogue are in the sun protection shop, in several textures and finishes. Which one suits each case — and above all which one you will genuinely use every day — is what is decided by looking at the skin.

Frequently asked questions

SPF 30 or SPF 50?

For daily facial use by someone wanting to prevent photoageing and pigmentation, a high factor makes sense. But the difference between 30 and 50 matters less than the amount applied and reapplication: at high factors, under-applying loses protection faster than the missing amount would suggest. A 30 properly applied and repeated does more than a 50 badly applied.

How much do you have to put on your face?

The official reference is by area: 2 mg/cm², which for the whole body of an adult comes to about six teaspoons. Translated to the face, almost everyone falls short: real-world application studies find medians below half of what is needed. The useful rule is simple: more than you think, and not forgetting ears, neck and the backs of the hands.

Do you have to reapply it even if you are not going to the beach?

The rules require the pack to say to reapply frequently, especially after perspiring, swimming or towelling, and prohibit declaring that it lasts all day. On an office day the exposure is lower, but if there are journeys, a terrace or a window, reapplying at midday is the sensible thing.

Does the SPF in my moisturiser or my make-up count?

It is better than nothing, and it usually falls short for the same old reason: the amount. Nobody applies the trial dose of a foundation. If the aim is real prevention, a sunscreen as such is the thing, with the make-up on top.

In winter or on cloudy days too?

UVA radiation goes through cloud and glass, and it is the most implicated in photoageing. If the aim is to prevent pigmentation and wrinkles — not just to avoid burning — daily use is what has the trial behind it: that study compared precisely daily use against use when it seemed necessary, and the difference was 24%.

Does a tinted sunscreen protect more?

In one specific respect, yes. The colour of a sunscreen usually comes from iron oxides (CI 77491, CI 77492, CI 77499), which absorb visible light — the part of the spectrum SPF does not measure and which does pigment medium and high phototypes. In melasma, a sunscreen with iron oxide improved the MASI 15% more than a UV-only one of the same factor. For every other aim — sunburn, photoageing — the difference is not relevant.

Are mineral sunscreens safer?

Both types authorised in the European Union are assessed within the same regulatory framework. The choice between mineral and organic is about tolerance and finish, not safety. On reactive skin or after a procedure, mineral is usually more comfortable; for daily use under make-up, the texture of organic filters makes it more likely to be used.

Does sunscreen prevent skin cancer?

This page is about photoageing and about choosing a product. Preventing skin cancer is a medical subject with recommendations of its own that go beyond a cosmetic — they include clothing, shade, avoiding the middle of the day and check-ups. Any lesion that changes colour, size or shape should be looked at in the consulting room, with or without sunscreen.

Sources

• Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Annals of Internal Medicine, 2013;158(11). PMID 23732711. — Randomised community trial in 903 adults under 55, with 4.5 years of follow-up and four groups (daily or discretionary sunscreen × beta-carotene 30 mg or placebo). The daily-use group showed 24% less skin ageing (odds ratio 0.76). Beta-carotene had no overall effect on skin ageing.
• Commission Recommendation of 22 September 2006 on the efficacy of sunscreen products and the claims made relating thereto (2006/647/EC). Text in the BOE. — Test quantity: 2 mg/cm², “which is equivalent to six teaspoons of lotion (some 36 g) for the whole body of an average-sized adult”. UVA protection at least 1/3 of the sun protection factor. Four labelling categories: low, medium, high and very high. Claims of 100% protection (“sunblocker”, “total protection”) should not be made, nor claims that reapplication is unnecessary (“all-day prevention”); the statement “To maintain protection, reapply the product frequently, especially after perspiring, swimming or towelling” must appear. Point 14 and its table, verified against the EUR-Lex text on 28-08-2026: “Low protection” → 6 (measured 6-9.9) and 10 (10-14.9); “Medium protection” → 15 (15-19.9), 20 (20-24.9) and 25 (25-29.9); “High protection” → 30 (30-49.9) and 50 (50-59.9); “Very high protection” → 50+ (≥ 60). Recommended minimum UVA protection factor: 1/3 of the SPF stated on the label, for all categories. Recommended minimum critical wavelength: 370 nm. Point 15: the category must be indicated at least as prominently as the sun protection factor. Minimum efficacy (point 10): SPF 6 against UVB by the International Sun Protection Factor Test Method (2006) or an equivalent in vitro method. Verified against the official text on 27-08-2026; category table added and verified on 28-08-2026.
• Castanedo-Cazares JP, Hernandez-Blanco D, Carlos-Ortega B, Fuentes-Ahumada C, Torres-Álvarez B. Near-visible light and UV photoprotection in the treatment of melasma: a double-blind randomized trial. Photodermatology, Photoimmunology & Photomedicine, 2014;30(1):35-42. PMID 24313385. — Randomised, double-blind trial in 68 patients with melasma (61 completed), assigned to a UV + visible light sunscreen with iron oxide or to a UV-only sunscreen, both at SPF ≥ 50, for 8 weeks, all of them on 4% hydroquinone as depigmenting treatment. At 8 weeks the UV-visible light group showed improvements 15% greater on MASI, 28% greater on colorimetry (L\*) and 4% greater on the histological assessment of melanin. ⚠️ A population with melasma and on hydroquinone treatment: the result does not carry over to general sun protection. It is the same source that already underpins the corresponding section of /en/melasma/.
• Carrao AM, Coleman JC, Guo JJ, Kumari H. A novel online survey approach designed to measure consumer sunscreen application thickness. Journal of Exposure Science & Environmental Epidemiology, 2024. PMID 37898625. — A survey of more than 9,000 people in the United States: mean facial application of 3.00 mg/cm² with a median of 1.78, and mean body application of 1.52 with a median of 1.35. In its historical review, 36 of 38 published values fell below the reference 2 mg/cm².
• Novick R, Anderson G, Miller E, Allgeier D, Unice K. Factors that influence sunscreen application thickness and potential preservative exposure. Photodermatology, Photoimmunology & Photomedicine, 2015. PMID 25771707. — Geometric mean applied thickness: lotion 1.1 mg/cm², spray 1.6 mg/cm², stick 0.35 mg/cm².
• Liu W, Wang X, Lai W, et al. Sunburn protection as a function of sunscreen application thickness differs between high and low SPFs. Photodermatology, Photoimmunology & Photomedicine, 2012. PMID 22548392. — Protection from low-SPF products showed a linear relationship with the applied dose, while in high-SPF ones the relationship with thickness was exponential: consumers get considerably less protection than expected from high factors that are under-applied.
• Diaz A, Neale RE, Kimlin MG, Jones L, Janda M. The children and sunscreen study: a crossover trial investigating children’s sunscreen application thickness. Archives of Dermatology, 2012. PMID 22250190. — Median application in children of 0.48 mg/cm²; 0.75 with a pump and 0.57 with a squeeze bottle.
• Regulation (EC) No 1223/2009 of the European Parliament and of the Council on cosmetic products. Text in the BOE. — The framework governing the ultraviolet filters authorised in the European Union and their safety assessment.

Book your consultation

If the reason you do not use sunscreen daily is the texture — it shines, it feels heavy, it leaves a white cast, it does not hold up under make-up — that problem has a solution and is worth solving: it is the only product in the washbag with a four-and-a-half-year trial behind it. At an assessment we pick the one that fits your skin and your routine, which is the one you will actually put on.

Clinical confirmation by the surgeon

Dr Enrique Salmerón González

Specialist in Plastic, Aesthetic and Reconstructive Surgery
Registration no. 46/4624077

Dr Elena García Vilariño

Specialist in Plastic, Aesthetic and Reconstructive Surgery
Registration no. 46/4624503

Last reviewed: 17 September 2026. This content is for information only and does not replace an individual assessment by a healthcare professional.