Vitamin D is one of the most important vitamins. It plays a critical role in helping your body absorb calcium, supporting your immune system and keeping your muscles and brain cells functioning properly.
However, unlike most vitamins and minerals, it isn’t found in many food sources. Instead, most people get their vitamin D from sunlight.
How? The process of converting sunlight into vitamin D starts in your skin.
“When your skin is exposed to UVB rays from sunlight, it converts 7-dehydrocholesterol, a compound in the skin, into pre-vitamin D3,” says Dr. Tia Paul, a board-certified dermatologist and founder of Balanced Skin Dermatology and Aesthetics.
This nutrient is then converted by the liver and kidneys into its active form, calcitriol, which is a form of vitamin D.
Without enough vitamin D, you can become more prone to frequent or recurrent infections, joint and muscle weakness, difficulty walking, bone fractures, fatigue and low mood.
[READ: What’s the Best Time to Take Vitamins?]
Benefits of Vitamin D
Vitamin D offers the body a host of benefits. These include:
— Building strong bones. Adequate vitamin D levels facilitate the absorption of calcium and phosphorus, which is key for building and maintaining strong bones. Without enough vitamin D, bones can become thin, brittle and more prone to fractures.
— Supporting your immune system. Maintaining optimal vitamin D levels, specifically around 40-60 nanograms per milliliter (ng/mL), may help you stay healthy. Research suggests that vitamin D can play a role in protecting you from viral and bacterial infections and chronic inflammation.
— Boosting muscle strength. Resistance training and consuming enough daily protein are two of the most well-known ways to promote muscle growth and enhance strength, but vitamin D may also be involved. Low vitamin D levels have been linked to muscle weakness and a higher risk of falls, especially in older adults.
— Promoting mood and brain health. Studies suggest that vitamin D supplementation can help regulate mood and protect brain function. Similarly, low levels have been associated with an increased risk of depression and cognitive decline.
— Supporting skin health. Vitamin D has anti-inflammatory properties that may help certain skin conditions, like psoriasis.
With its myriad benefits, you may wonder: How much sun do you need to reap them?
[READ: Should You Take a Multivitamin?]
How Much Sun Does Your Body Need to Get Enough Vitamin D?
Generally, getting anywhere between 10 to 30 minutes of sunlight midday, a few times a week, is sufficient. However, this depends on your skin tone, age and location.
“As a dermatologist, I always emphasize balance. Aim for brief, unprotected sun exposure on small areas, like the forearms, for about 10 to 15 minutes a few times a week,” Paul says.
After that, it’s important to apply a broad-spectrum sunscreen to your face and body with SPF 30 or higher every two hours.
“Use sunscreens with zinc oxide or titanium dioxide for sensitive skin and reapply every two hours if you’re outdoors,” Paul says. “Wearing hats, sunglasses and sun-protective clothing can help you enjoy the sun safely without increasing your risk of skin cancer.”
During the winter or for those living in northern latitudes, you may need to rely more on food and vitamin D supplements to maintain adequate levels in their body.
While some research has shown that sunscreen — which works by blocking UVB light — may interfere with your body’s UV absorption and vitamin D production, the prevailing wisdom from experts is to wear sunscreen every day nonetheless. Most clinical studies demonstrate that people who wear sunscreen regularly can still absorb enough UVB rays to maintain vitamin D levels.
[SEE: Best Vitamins and Minerals for Older Adults.]
Other Ways to Get Vitamin D
Not everyone has access to (or the opportunity to get) direct sunlight several days a week, which is why many need to fill in those nutrient gaps with dietary choices.
Foods rich in vitamin D include:
— Fatty fish, like salmon, mackerel and sardines
— Egg yolks
— Beef liver
Dietary supplements are another great way to get adequate levels of the nutrient. But choose your supplements wisely and do your research, the experts advise.
Choose a vitamin D3 supplement over a vitamin D2 option, as your body absorbs the former more easily. Also, consider pairing your D3 supplement with a vitamin K2 supplement (if your doctor gives you the OK).
“These two nutrients work together to absorb and transport calcium directly to your bones and teeth,” says Dr. Will Haas, the founder and CEO of VYVE Wellness, a wellness clinic specializing in integrative medicine, wellness and longevity.
But before you purchase any supplement, make sure it’s been third-party tested by NSF International or US Pharmacopeia to make sure the product matches what’s on the label and does not contain contaminants.
“Stick with well-known brands and look for third-party certifications,” says Dr. Meghan Garcia-Webb, a physician who’s triple board-certified in internal medicine, lifestyle medicine and obesity medicine.
What’s the right dose?
Often this requires a conversation with your doctor and what’s best for you, as this depends on a variety of factors, including skin tone and age. People with darker complexions and older adults require more vitamin D than fair skin and younger populations, respectively.
However, it’s important not to overdo it. While other vitamins are water soluble, meaning they dissolve in water and are not stored in the body, vitamin D is a fat-soluble nutrient, which dissolves in fat or oil and can be absorbed and stored in the body. Therefore, consuming too much vitamin D can lead to toxicity.
“The tolerable upper intake level is 100 micrograms — or 4,000 international units,” Garcia-Webb says. “I don’t advise taking more than 2,000 international units daily without speaking to your physician.”
Bottom Line
Vitamin D plays a critical role in your overall health. The most natural way to get your regular dose of the vitamin is direct sunlight.
However, that’s not always the most realistic (or safest) option for everyone. Talk to your doctor about any health conditions you may have and how to safely increase your vitamin D intake either via diet or supplementation. A registered dietitian can also help provide tailored guidance on dietary approaches for getting enough vitamin D and other nutrients.
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How Much Sun Do You Need for Vitamin D? originally appeared on usnews.com
Update 06/12/25: This story was previously published at an earlier date and has been updated with new information.
