Can Sunscreen Cause Vitamin D Deficiency in a British Summer?

You might assume that a British summer, once it eventually arrives, can put almost anything right. Jumpers are tucked away, pub gardens fill up, and we all head outdoors to “topping up our vitamin D” like solar-powered humans. My friend Emma was that exact person this year: out for a walk every morning, scrupulous with SPF 50, and quietly pleased with herself. Then her GP called with her blood results and said she was “deficient”. In August. During a heatwave. She looked at her phone wondering how she could possibly still be low.

If you faithfully apply high-factor sunscreen and still turn out to have vitamin D deficiency, you are far from the only one. That heavy mid-afternoon fatigue, the faintly brittle mood that will not shift, the sore muscles you put down to “getting older” - all are easy to overlook. Yet it is quietly disconcerting when your body seems to signal that something is absent, and a test confirms it. The odd thing is that you may be following precisely the advice considered “right”. That is where things become interesting.

The summer myth we are happy to believe

In the UK, we tend to cling to a comforting myth: summer comes, daylight stretches out, and any vitamin D problems simply resolve themselves. We imagine soaking up sunshine at barbecues, taking the dog out in warm evening light, and taking in rays like a houseplant by the window. In practice, much of that time happens beneath clouds, in shade, behind glass, or covered in enough SPF to withstand Mercury. Then September blood results show we are still running on empty, and we are somehow surprised.

Most of us know the moment when a GP asks, “Do you get out in the sun much?” and we automatically reply, “Yes, loads,” before thinking it through. But do you? Or do you dash from the front door to the car, from the office to Pret, and convince yourself that a ten-minute walk to the station qualifies as “plenty of sunshine”? The difference between the outdoor life we imagine we lead and an ordinary weekday is larger than we care to acknowledge. Vitamin D exists squarely in that awkward space.

There is also an unstated assumption that every warm day provides strong vitamin D. A cloudy afternoon with bare arms may feel like summer, yet if the UV index is low - or factor 50 covers your skin - your body may produce very little. It is rather like believing your muscles will become toned merely by being in the same room as a gym. A nice thought, but not how the body works.

How sunscreen alters the vitamin D balance

This can seem unfair: the product you use to guard against skin cancer may also prevent the UVB rays your skin requires to produce vitamin D. When high-SPF sunscreen is applied correctly and regularly, it can greatly reduce vitamin D production. That is exactly what it is made to do. SPF 50 does not merely filter a small amount; it blocks most burning UVB, which is also the wavelength that starts your skin’s vitamin D-making process. Nothing is wrong with you. Your sunscreen is simply doing its job extremely well.

Most of us do not apply sunscreen as the instructions specify - two full finger-lengths on the face, a shot-glass amount over the body, reapplied every two hours and more often after swimming or sweating. Realistically, hardly anyone manages that every day. However, if you are among the unusual few who come close - diligent, fair-skinned, anti-wrinkle people who never allow their nose to see daylight - your vitamin D production may be seriously affected, particularly in a country where sunshine is already scarce for half the year.

The face, arms and areas that never see daylight

One small point makes a difference: which parts of your body receive sunscreen. Many of us use SPF 50 on the face every day, whether to prevent skin ageing or cancer, and perhaps apply it to the arms and chest when the weather is sunny. If your face is always protected and work usually means long sleeves, very little skin remains available to do the work. A small uncovered section of wrist will not miraculously raise your levels, however reliably you walk to the coffee shop.

For those who keep their bodies covered for cultural, personal or medical reasons, the impact can be greater still. A person in long sleeves and a head covering who also wears high-SPF sunscreen may spend hours outside without producing much vitamin D. The sun and warmth are present, but the skin and the rays do not properly meet in the way required.

Why blue skies do not stop you feeling tired

Feeling low when the weather is finally pleasant is particularly frustrating. You expect the winter blues: January’s gradual heaviness and the 4pm darkness that leaves you wanting carbohydrates and pyjamas. If it is July and you are dragging yourself through the afternoon as though your brain is moving through custard, it seems wrong. You may blame work, sleep, your phone, or anything other than the hormone quietly associated with energy and mood.

Vitamin D has functions beyond bone health. It contributes to immune function, muscle strength, inflammation and even the way the brain operates. Low levels may show up as indistinct fatigue, a weaker grip, more colds, or a lingering flatness that is difficult to explain. It is not a dramatic, soap-opera illness; it is simply life feeling slightly more difficult than it ought to. On hearing “deficiency”, you may think of rickets in a Victorian history book, rather than an exhausted 35-year-old scrolling on the sofa.

There can be a quiet sense of shame, too. How can you be low in sunshine while living among open parks and Instagram sunsets, surrounded by wellness posts insisting that you should “go outside more”? It can feel like getting something fundamental wrong, rather like failing to drink enough water or hitting snooze three times. You may brush it aside, tell yourself you will buy “some vitamins at some point”, and remain quietly stuck.

The UK latitude problem few people mention

A dull-sounding term has considerable influence here: latitude. The UK is sufficiently far north that, from around October to March, sunlight does not contain enough UVB for your skin to create vitamin D, however determinedly you stand outside in shorts. You could sunbathe at midday in Edinburgh in November and produce virtually nothing. The sun is visible, but its angle is unsuitable for the chemistry your body needs.

That means many of us enter spring already at a disadvantage. By May or June, a great number of people are considerably depleted after winter. Summer then arrives as both a rescue mission and a race against time. When weekends are full, weekdays take place mainly indoors, and your brief periods outside involve SPF 50, you may not restore your levels as much as you expect. The tank does not quite get full.

Clouds, work and sunlight in real life

Cloud cover, unreliable weather and ordinary life also matter. There may be hot days, but there can equally be weeks of grey, windy drizzle in which your “summer” scarcely feels like one. Many people work through peak UVB hours under strip lighting and air conditioning, only emerging once the sun has begun to drop. Fifteen warm minutes on a balcony may be pleasant, but it is very different from a midday walk for vitamin D production.

At this point, sunscreen becomes more than a minor consideration. For somebody on night shifts or long working hours who sees the sun only at unusual times, a short period of midday exposure might be their sole genuine opportunity to make vitamin D through the skin. If high-SPF sunscreen and clothing fully block that opportunity every time, the balance shifts in the wrong direction. You gain all the skin-risk reduction, with little in return for bones, muscles and mood.

Can you combine strong sun protection with good vitamin D?

This is the question many people quietly carry: must I choose between preventing wrinkles and preventing deficiency? The brief answer is no, though it may require a different idea of what being “sun-safe” means. Dermatologists are right to stress SPF: skin cancer rates are increasing, and childhood sunburn or repeated burns in adulthood present genuine problems. Even so, most experts also recognise that a limited amount of unprotected sunshine on bare skin at an appropriate time can help with vitamin D.

Some people take a middle route, allowing 10–15 minutes of midday sun on larger areas such as the arms and lower legs before using sunscreen, particularly in late spring and early summer, then covering up carefully for the rest of the day. This is not permission to sunbathe until you burn, but a short and deliberate window. Others, especially people with very fair or sensitive skin, avoid this altogether and use supplements, allowing tablets rather than sunlight to do the work. Both approaches are valid; what matters is being intentional rather than guessing.

Supplements, food and the quiet back-up plan

Diet alone seldom supplies enough vitamin D to correct a genuine deficiency, although it can add to your intake. Oily fish, egg yolks, liver, fortified spreads and cereals each provide small amounts. For many people, the real difference comes from a daily supplement, especially in places such as the UK where health authorities already advise taking one in the darker months. A straightforward capsule or spray can support your levels while you remain careful with SPF.

There is something reassuring in knowing that you do not need to manage this perfectly every day. You can use SPF 50 on your face throughout the year, sit in the shade and avoid burning completely, while a small tablet fills the gap. For people who cover most of their skin, or who have darker skin and therefore produce vitamin D more slowly, that is not “cheating”; it is a practical solution. The real danger is not sensible supplement use - it is spending years shrugging and assuming summer sunlight will somehow solve everything when it does not.

The subtle warning signs you may be overlooking

Low vitamin D does not make everyone dramatically unwell. Some people simply feel… off. Your legs may ache after a brief walk, shopping bags might feel harder to lift because your grip seems weaker, or you may tire more quickly than before. Perhaps colds are frequent, or your mood falls for no obvious reason even though, on paper, life appears fine. These signs are easily labelled “stress” or “getting older”, particularly when nobody around you seems visibly concerned.

Then there is the slightly uncomfortable GP discussion after a routine blood test. You may hear phrases such as “on the lower side” or “we’d like to supplement you for a bit”. Most people agree, take the high-dose prescription, vow to “go outside more”, and leave the surgery only to return to the same routine. There is no spectacle or blue flashing lights, merely a quiet turning point at which you either take notice or carry on drifting.

What is often overlooked is the slow way this develops. You do not wake one day with “vitamin D deficiency” written across your forehead. Months or years of borderline levels, combined with habits such as constant high-SPF use and an indoor lifestyle, may gradually push you into deficiency. By the time something feels wrong, the patterns are so familiar that they disappear from view: commuting, office life, sunscreen, shade and evenings inside. The narrative unfolds without you noticing.

Rethinking what “healthy sun” means

There is an emotional aspect worth acknowledging. Many of us use high-factor sunscreen because we are frightened: of burning, ageing, or the questionable mole we keep checking in the mirror. Some have watched someone close to them experience skin cancer, or have undergone a biopsy themselves, so SPF feels like armour. Hearing that this same protection could be lowering vitamin D can feel almost disloyal, as if health advice has contradicted itself yet again.

Perhaps the solution is not to choose a side - sunscreen or sunshine - but to take a more curious look at your own life. How often are you genuinely in midday light with some skin uncovered before using the bottle? Do you know your most recent vitamin D level, or are you estimating it from the amount of “outdoorsy” content you have watched on social media this week? A blood test, a modest supplement, a few deliberate minutes in the sun and reliable SPF afterwards are not dramatic measures. They are simply a quieter and more honest form of “being healthy” than relying on hazy assumptions and half-remembered headlines.

The next time you are in a café garden, warmth on your arms and a white streak of sunscreen visible where you missed your wrist, consider what your skin may be doing underneath. It is not only ageing or freckling; it is also attempting to produce a hormone that your entire body quietly depends upon. You’re allowed to protect your skin and still ask whether your vitamin D needs a bit of help. That is neither vanity nor fussiness; it is the kind of adult attention that our sun-soaked, sunscreen-covered summers rarely receive.