SunticVitamin D and the Sun: How Much Do You Really Need?
Vitamin D is often used to justify long sessions in the sun, on the logic that if a little sunlight is good, more must be better. It is one of the most persistent reasons people give for skipping sun protection. In reality, the amount of sun your body needs to make vitamin D is small, and going beyond it adds UV damage without adding any benefit. Here is what the science actually says. This is general information, not medical advice.
How does your skin make vitamin D?
When UVB rays reach your skin, they kick off a process that produces vitamin D. Because it depends on UVB specifically, it only happens when the sun is high enough, broadly when the UV index reaches about 3 or above. Below that, as Cancer Council Australia notes, the body makes very little vitamin D no matter how long you stay out. This is also why latitude and season matter so much: in higher-latitude countries, the NHS notes that from around October to early March the sun is simply too low for most people to make enough vitamin D at all.
Can you store it up by burning?
This is the part that undercuts the long-session logic. The Skin Cancer Foundation explains that a short amount of exposure produces all the vitamin D your body can use at once, after which it starts breaking the surplus down to avoid overload. Staying out longer does not keep topping up your vitamin D, it just keeps adding UV damage. There is no biological reward for burning, only cost.
Why do authorities not recommend sunbathing for it?
No major health body recommends deliberate sunbathing as a way to get vitamin D. Cancer Council Australia states plainly that overexposure to UV is never recommended, even if you are low in vitamin D. The reassuring flip side is that everyday sun protection does not doom you to deficiency: research summarised by the same body suggests sunscreen has minimal impact on vitamin D levels over time, because you still get incidental exposure. You do not have to choose between protecting your skin and maintaining vitamin D.
Diet and supplements are the recommended route
When sunlight is not enough, food and supplements fill the gap. Oily fish such as salmon and mackerel, eggs and fortified foods all provide vitamin D. In the UK, the NHS advises that everyone consider a daily supplement containing 10 micrograms of vitamin D during autumn and winter, and year-round for people at higher risk. Treat that as general public-health guidance rather than a personal prescription: if you are worried about your levels, a doctor can test them and advise properly.
Are sunbeds a good vitamin D source?
Tanning beds are sometimes pitched as a vitamin D source, but they emit mostly UVA, which does little for vitamin D while raising cancer risk. We cover why in tanning beds vs the sun. If your aim is vitamin D, a supplement is both safer and more reliable than any UV source.
Get the incidental sun you need, and no more
The practical goal is simple: get the short, everyday exposure that supports vitamin D, then protect yourself for anything beyond that. Suntic shows the live UV index for your location, so you can see at a glance whether the sun is even strong enough to make vitamin D, and it estimates a personalised safe-sun time so longer spells outdoors stay within sensible limits. It is a guide for good habits, not a substitute for professional advice on your vitamin D.
Frequently asked questions
How much sun do I need for vitamin D?
Usually only a few minutes of incidental exposure on most days, when the UV index is about 3 or higher. Beyond that brief window your body cannot use any more vitamin D at once, so longer sessions add UV damage without extra benefit.
Can you get vitamin D in winter?
In higher-latitude countries the winter sun is often too low to make much vitamin D, which is why the NHS suggests considering a daily 10 microgram supplement in autumn and winter. Diet and supplements are the recommended sources when sunlight is insufficient.
Does sunscreen stop you making vitamin D?
Not meaningfully. Because people still get incidental exposure, research suggests everyday sunscreen use has minimal impact on vitamin D levels over time. You do not have to skip sun protection to maintain your vitamin D.
