Sun Protection and Vitamin D
Vitamin D plays an important role in your health, and so does protecting your skin from harmful amounts of UV. There are safe ways to get enough vitamin D, and research continues to look at how vitamin D may play a role in risk.
What is vitamin D?
Vitamin D is a hormone and a nutrient. Its primary function is to keep bones and teeth strong by helping the body absorb and use calcium and phosphorus in the right way.
Vitamin D has many important health benefits. It helps manage:
- Inflammation (swelling) and the growth of cells
- Muscle strength
- How well the immune and lymph system and nervous system work
Studies also suggest that having low vitamin D levels could be linked to seasonal affective disorder and mood changes.
Where does vitamin D come from?
Vitamin D can come from sunlight or from what you eat. It also comes in two main forms, D2 and D3, depending on the source.
Sunlight
Your skin makes vitamin D naturally when it is exposed to UV rays. Most people get at least some of their vitamin D this way, through natural sunlight. The outer layer of the skin (the epidermis) starts the process of making vitamin D in response to sun exposure.
How much vitamin D your skin can produce depends on:
- How old you are
- How dark your skin is
- How strong the sunlight is where you live
- Whether you wear clothing with UPF or sunscreen with SPF
- Whether you have other health problems
Food and supplements
Not many foods naturally have vitamin D. It’s often added to foods and drinks. If your vitamin D is low, your doctor might prescribe or recommend vitamin D supplements for you.
A few ways to make sure you’re getting enough vitamin D:
- Include vitamin-D-rich foods in your diet. These include fatty fish such as salmon, trout, swordfish, and tuna. Eggs and mushrooms also contain small amounts of vitamin D.
- Milk, including soy and almond milk, is fortified with vitamin D. Some other dairy products, orange juice, and cereal also can have vitamin D added. Read labels to be sure.
- If you take a calcium supplement, you may already be getting added vitamin D. Some calcium supplements contain vitamin D.
Types of vitamin D
There are 2 main types of vitamin D:
- Vitamin D2 is mostly made in a lab and added to foods and supplements.
- Vitamin D3 is the type your body makes from sun exposure. It can also come from eating certain foods and taking supplements.
Does sunscreen block vitamin D?
Most research has found that using a lower SPF (SPF 15) sunscreen does not lower vitamin D levels. Some research has found that vitamin D levels may decrease when using a higher SPF sunscreen.
However, more research is needed on higher-SPF sunscreens (SPF 30 to 100+) to find out how factors like weather, age, and skin type affect vitamin D levels when using sunscreen. This research could help explain how sunscreen affects vitamin D absorption to improve guidance on safe sun exposure.
Experts continue to recommend using broad-spectrum SPF 30 or higher to protect your skin from harmful UV rays. Broad-spectrum sunscreen protects against UVA and UVB rays.
If you’re concerned about your vitamin D levels, talk to a member of your healthcare team.
Am I getting enough vitamin D while protecting my skin?
There are ways to check whether you’re getting enough vitamin D. And there are ways to get a healthy amount of vitamin D safely without sun exposure.
Testing vitamin D levels
The best way to know if you’re getting enough vitamin D is with a blood test, 25-hydroxyvitamin D, that measures your levels. Your doctor might recommend this test if you have certain health conditions, such as liver disease or have had bariatric surgery. Your doctor might also recommend the test if you take certain medicines that might lower your ability to absorb vitamin D, such as laxatives or steroids.
If your blood test shows that you’re not getting enough vitamin D, your doctor may recommend a vitamin D supplement. Your doctor can let you know a safe dose to take. Be sure to follow your doctor’s recommendations because taking too much vitamin D can be harmful.
Getting vitamin D safely
Although vitamin D is made naturally when the skin is exposed to UV rays, it’s best to get vitamin D from your diet or vitamin supplements. It’s important to remember the harmful effects of UV rays from sunlight and tanning devices.
Recommended daily amounts of vitamin D in International Units (IU):
- Children younger than age 1 should get 400 IU.
- People ages 1 to 70 should get 600 IU.
- Adults older than 70 should get 800 IU.
Does vitamin D protect against cancer?
Research on a link between vitamin D and cancer is mixed. Some studies have shown that people with low vitamin D levels might have a higher risk of getting cancer or dying from cancer. However, it’s not clear whether taking vitamin D or having certain vitamin D levels might help prevent cancer.
It’s also not clear whether vitamin D can help control the growth and spread of cancer. More research is needed to understand if vitamin D helps to prevent or control cancer.
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The 黑料大湿Posts Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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Last Revised: September 1, 2026
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