Vitamin D is essential for healthy bones, teeth and muscles. But does sunscreen block vitamin D synthesis? We look at the latest research, explain how your body makes vitamin D from sunlight, and cover when supplementation makes sense. The short answer: you can protect your skin and maintain healthy vitamin...
Vitamin D is essential. Full stop.
It helps the body absorb calcium and phosphate, which means healthy bones, teeth and muscles. Without enough of it, you risk bone pain, muscle weakness, and in severe cases, conditions like rickets in children or osteomalacia in adults.
There's also growing evidence that vitamin D contributes to immune function, mental health and mood. The research is still evolving, but one thing is certain: a lack of vitamin D can cause problems.
So let's talk about how you get it, what happens in a British winter, and why the "SPF blocks vitamin D" thing is mostly nonsense.
You might have seen both on supplement labels. Here's the difference:
Vitamin D3 is what your skin makes when UVB light hits it. It's also found in animal sources like oily fish, eggs and meat. Your body absorbs D3 more efficiently and it stays in your system longer.
Vitamin D2 comes from plant sources (like certain mushrooms exposed to UV light). It's fine, but D3 is the more effective option, which is why most supplements use it.
When we talk about vitamin D holistically, we mean both. But if you're buying a supplement, go for D3.
Two ways: sunlight and diet.
When UVB light from the sun hits your skin, it converts a compound called 7-dehydrocholesterol into vitamin D3. Body heat then completes the process. No sunbeds required, no miracle creams needed. Just your skin, daylight, and a bit of time.
In the UK, between late March and September, you can make enough vitamin D from regular sun exposure. That's roughly 10–15 minutes of midday sun on your forearms, hands or face, a few times a week.
But here's the catch: between October and early March, the sun's angle means UVB levels are too low for your skin to synthesise vitamin D. Even on a crisp, sunny February afternoon, you're not making any. The sun just isn't strong enough at this latitude.
That's why the NHS recommends everyone in the UK considers taking a 10-microgram (400 IU) vitamin D supplement daily during autumn and winter. Not because of a deficiency crisis, but because sunlight alone isn't cutting it for half the year.
Some foods contain vitamin D, but not in huge amounts:
To hit the recommended 10 micrograms a day through food alone, you'd need about one salmon fillet or five eggs. Every day. Which is why supplementation makes sense for most people during the darker months.
Not everyone synthesises vitamin D at the same rate.
Melanin (the pigment that determines skin colour) is your body's natural UV defence. The more melanin you have, the more time you need in the sun to produce the same amount of vitamin D. People with darker skin may need significantly longer exposure than those with lighter skin.
Adipose tissue (body fat) stores vitamin D, which can reduce how much is available in your bloodstream. So obesity is a risk factor for low vitamin D levels.
Age also plays a role. As you get older, your skin becomes less efficient at making vitamin D.
The general guidance from health professionals is 10-15 minutes of midday sun exposure during the warmer months (March to September). For people with darker skin, this may need to be longer.
And here's the important bit: that guideline is for non-burning exposure. Sunburn increases skin cancer risk. Even a few serious burns over your lifetime raise the risk of melanoma. So the goal is sensible, short bursts of daylight. If you're going to be outside longer, or your skin starts to redden, that's when you apply SPF.
This is the myth that won't die.
For years, there were concerns that sunscreen might contribute to vitamin D deficiency by blocking the UVB light needed for synthesis.
Then, in 2019, three separate studies published in the British Journal of Dermatology largely disproved this.
The most notable was led by Professor Antony Young from King's College London. His team sent participants on a week-long holiday to Tenerife (very high UV index, cloudless skies). They applied SPF 15 sunscreen optimally, multiple times a day, thick enough to prevent sunburn.
The result? Highly significant increases in vitamin D levels. Even with proper sunscreen use.
Professor Young said it clearly: "Sunscreens, even when used optimally to prevent sunburn, allowed excellent vitamin D synthesis."
The same study showed that people who used their own sunscreen (without instructions) also synthesised vitamin D, but they all got sunburned. That tells you everything you need to know.
Another 2019 systematic review analysed 75 studies spanning from 1970 to 2017 and reached the same conclusion: sunscreen use, even when applied generously and frequently, has no significant effect on vitamin D production.
Holly Barber from the British Association of Dermatologists summed it up: "The risk of vitamin D deficiency from sunscreen has been found to be low, and therefore is unlikely to outweigh the benefits of sunscreen for skin cancer prevention."
During a British winter, vitamin D deficiency isn't caused by your SPF use. It's caused by the fact that there isn't enough UVB in the sunlight between October and March for your skin to make any vitamin D at all.
Even if you spend time outdoors in January without sunscreen, you won't be synthesising vitamin D. The sun's angle is too low, the UVB intensity is insufficient, and no amount of fresh air on your face is going to change that.
What will help:
The NHS guidance is clear: everyone should consider supplementation during autumn and winter. Some groups (people who are housebound, those who cover their skin for cultural reasons, people with darker skin) should consider it year-round.
You can protect your skin and maintain healthy vitamin D levels. These things are not in conflict.
Between late March and September, short bursts of midday sun exposure are usually enough to keep your vitamin D topped up, even if you're using SPF. During autumn and winter, when UK sunlight is too weak for vitamin D synthesis, a simple daily supplement fills the gap.
Vitamin D deficiency is often used as a reason to skip sunscreen. But the science doesn't support it. Sunscreen might slightly reduce vitamin D production, but it doesn't stop it. You can protect your skin from UV damage and still make plenty of vitamin D from regular, non-burning daylight exposure.
And during the months when the sun's too weak? That's what supplements are for.
Get outside. Protect yourself when it matters. Top up with D3 when it doesn't. Sorted.
Products that help you put this into practice.
Daily moisturiser with SPF 30. One step and your skin's protected.
Your cart is currently empty.
Start Shopping
Daily moisturiser with SPF 30. One step and your skin's protected.
