Soaking Up the Sun: When Is the Best Time to Take Vitamin D?

3/4/2025 • Austin Ruff

If you’re like me, you regularly don’t get enough sunshine throughout the year. In the summer, heat and humidity – and an indoor desk job – may keep us inside. In the winter, short daylight hours and cold temperatures continue to keep us indoors.

Missing out on sunshine can have a potentially unhealthy side effect – a deficiency in vitamin D. These times of year are often the best time to take vitamin D supplements, whether in a single-nutrient capsule, as a liquid droplet, or in a multi-vitamin/mineral formula.

Knowing when to take vitamin D supplements is the easiest way to avoid a low level of vitamin D year-round.

If you’ve been wondering about a good time to take vitamin D, you may have questions like the following:

When should you take vitamin D?
Can you take vitamin D at night?
How much vitamin D should I take in the winter?
What helps vitamin D absorption?

This article will answer these questions and more.

What is vitamin D? When is the best time to take vitamin D?

Vitamin D is an essential nutrient that supports bone and muscle structure, immune function, cardiovascular health, hormone balancing, healthy skin, a good mood, and more.*

Although the body can obtain vitamin D from certain foods, given the right circumstances most of our daily vitamin D need can come from sun exposure. When skin is exposed to the ultraviolet rays from the sun, a chemical reaction begins in the body that turns that glorious sunshine into vitamin D. As few as 10-20 minutes with your arms and legs exposed to the midday sun several times a week can typically provide adequate vitamin D.

But for many individuals, sun exposure isn’t enough to produce vitamin D. Whether through lifestyle factors or genetics, many factors can restrict the body’s ability to make vitamin D. If you’ve wondered if now is a good time to take vitamin D, consider how these factors impact you:

Geographical location. People who live in the northern latitudes receive less sun exposure – even in the summertime.
Season. Winter, even in southern U.S. regions, might not provide enough sunshine.
Lack of sun exposure from other causes. Air pollution, spending the majority of time indoors, using sunscreen, wearing clothing that covers most of the body all keep the sun out.
Skin pigmentation. A higher amount of melanin in the skin can inhibit the chemical reaction that makes vitamin D.
Aging. Older adults are less able to make vitamin D in the skin and are more likely to be housebound than younger adults.
Overweight. Excess fat can inhibit vitamin D’s absorption from the skin and sequester it in fat cells.
Even individuals who lead an otherwise active lifestyle with daily workouts could be lacking sufficient vitamin D because of extensive indoor training at the gym.

Vitamin D3 (the most potent form of vitamin D found in supplements) is found naturally in a limited number of foods, fish being the best source. For example, 3 ounces of rainbow trout or salmon typically contain 550-650 IUs of vitamin D, while there are roughly 40-50 IUs in one egg (in the yolk), 3 ounces of beef liver or tuna, or two sardines. Other foods that contain significant amounts of vitamin D because it is added (fortified) include cow milk, nut milks, orange juice, and breakfast cereals (read labels).

Vitamin D2 (a vegetarian source of vitamin D and less potent than D3) is found primarily in mushrooms exposed to UV light. For example, a half cup of white mushrooms exposed to UV light contains 366 IUs of vitamin D2, while the same amount of portabella mushrooms contains only 4 IU.¹

According to a 2016 USDA analysis, 92 percent of men and 97 percent of women get less than 400 IU of vitamin D from food and beverage sources.²

Because of these factors, many individuals take a vitamin D supplement to ensure adequate intake.

How to take vitamin D properly

Knowing when to take vitamin D and how much to take is not an easy, one-size-fits-all answer. The ideal amount depends on what your current vitamin D status is, what your health concerns are, and whether you are in a high-risk group for a deficiency.

The FDA recommends 800 IU daily as a baseline.¹ For bone health alone, Mayo Clinic recommends daily vitamin D supplementation of 600 IU for everyone between the ages of 1 and 70, and 800 IU for those older than 70.³While these are conservative recommendations, it is likely that if you are already low in vitamin D, then these amounts won’t be sufficient to bring your blood level up to what is considered sufficient – 32 ng/mL by conventional standards and 40 ng/mL or higher for optimal health.

Estimates for daily vitamin D recommendations often assume you are starting out with an adequate blood level. Because of the myriad vitamin D benefits and processes in which it is involved, additional supplementation might be optimal.

Thorne has an easy at-home Vitamin D Test that measures how much vitamin D you have in your bloodstream with a simple finger prick. The results come with personalized diet and lifestyle recommendations to improve or maintain your vitamin D levels and help you answer questions like “When should you take vitamin D?” Be sure to discuss the results from Thorne’s Vitamin D Test with your health-care professional.

How much vitamin D should I take in the winter?

Because of limited daylight hours and more time spent indoors during the winter months, the FDA’s baseline of 800 IU may not be enough for many individuals. Taking a quality vitamin D supplement that delivers 1,000 IU of vitamin D or even as much as 10,000 IU may be beneficial.

When is the best time to take vitamin D? Can you take vitamin D at night?

If you’ve decided that now is the best time to take vitamin D to support your health, you may be wondering how best to add it to your daily routine.

What time of day is best for vitamin D? Health experts agree that vitamin D may be taken at any time of day, morning or night. With any healthy lifestyle habit, consistency is key.

While some anecdotal sources suggest that taking vitamin D at night may interfere with sleep, there is little research so far connecting vitamin D production with sleep disorders. If you do find that taking vitamin D at night affects your sleep, an easy solution is to switch your routine and take vitamin D in the morning instead.

What helps with vitamin D absorption and what is the best form of vitamin D to take?

To help with consistency, you may benefit from taking vitamin D with a meal. As a fat-soluble vitamin, vitamin D can be taken with fatty foods, like full-fat yogurt, avocado, or almonds.

For many, supplementing with vitamin D as a standalone capsule or as a multi-vitamin/mineral formula is the easiest way to take vitamin D. Again, consistency is key – when you supplement with vitamin D, supplement at the same time every day.

If you’ve decided to take a vitamin D supplement but you’re not a fan of capsules, you may be wondering about a liquid option and when to drink vitamin D. We previously mentioned that dairy milk is often fortified with small amounts of vitamin D. For versatility with your favorite beverage, try a liquid vitamin D supplement, which provides an easy and accurate way to personalize your supplement routine.

Thorne’s Vitamin D Liquid features a self-dispensing top to measure out individual drops and to help make supplementation easy to customize for adults and children; each two-drop serving provides 1,000 IU.

The takeaway

Supplementing vitamin D year-round can support most health goals, without needing to rely on the availability of and access to sunshine throughout the year. In addition to a full lineup of multi-vitamin/mineral products with vitamin D to fit your lifestyle and life stage, Thorne offers two forms of stand-alone vitamin D supplementation: a liquid that can easily be added by single drops to any smoothie or beverage – great for kids spending more time indoors as the school year begins – and an encapsulated form available in several dosages for daily convenience. For the indoor athlete, Thorne’s D-5,000 is NSF Certified for Sport®. And if you are wondering what your vitamin D levels are, Thorne offers an easy-to-use, at-home Vitamin D Test kit that provides results along with diet, lifestyle, and supplement recommendations based on your results.

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