How to Increase Vitamin D is a common question if you have been told that your vitamin D is low or if you simply suspect that your vitamin D might not be at an adequate level. Advice such as “eat more vitamin D” does not help much because very few foods contain high amounts of vitamin D, and advice such as “get more sun” has its own limits. What you really want is a practical plan that explains which sources of vitamin D truly matter, how much vitamin D they can provide, and when neither food nor sunlight alone may be enough.

This article covers the real, practical pathways food, fortified products, sensible sun exposure, and when supplementation and testing make sense without pretending everyone can fix low vitamin D by spending an extra ten minutes outside.

Can You Increase Vitamin D Naturally?

Your body gets vitamin D from three places: sunlight-triggered skin production, food, and supplements. In theory, “naturally” usually means the first two. In practice, how much either one can realistically raise your levels depends heavily on factors you don’t fully control where you live, your skin tone, your age, your diet, and any health conditions that affect absorption.

That’s not meant to be discouraging. Food and sun exposure genuinely do contribute to vitamin D status, and for many people, small consistent changes make a real difference. But for others, particularly people with several risk factors working against them at once food and sun alone may not be enough to reach an adequate level, and that’s worth knowing going in rather than discovering after months of frustration.

7 Ways on How to Increase Vitamin D

1. Get Vitamin D From Sensible Sun Exposure

Your skin produces vitamin D when UVB rays hit it directly this is the original, most efficient source for most of human history. But how much you produce from any given sun exposure depends on a long list of variables:

• Season and latitude: at latitudes above roughly 37°N (which covers most of the continental U.S. from the Bay Area to the mid-Atlantic and north), UVB intensity is too low for meaningful synthesis for several winter months, regardless of how long you’re outside.
• Time of day: UVB is strongest roughly between 10am and 3pm; early morning or late afternoon sun contributes far less.
• Skin pigmentation: more melanin reduces the skin’s efficiency at producing vitamin D from the same UVB exposure.
• Age: skin becomes less efficient at vitamin D synthesis as you get older.
• Clothing and sunscreen: both block UVB, which is the point of sunscreen, it’s protecting you from the same rays that trigger vitamin D production.
• Cloud cover and pollution: both reduce UVB penetration.

A right amount of time doesn’t really exist since the factors listed above would affect it so heavily. What we can definitely say is that short-term, non-burning midday sunlight on skin (arms, legs) several times a week could significantly help to boost one’s vitamin D levels during the warmer months of the year, especially in low latitude regions. It’s not a year-round practice everywhere, and it should definitely not be followed in such a way as to cause sunburn – sunburn won’t provide more vitamin D, it will just harm your skin.

2. Eat More Vitamin D-Rich Foods

Relatively few foods naturally contain meaningful vitamin D, which is a big part of why deficiency is so common. The best natural sources are fatty fish, egg yolks, and UV-exposed mushrooms (see the table below for specifics).

3. Choose Fortified Foods

Because natural food sources are limited, many U.S. products are fortified with vitamin D, meaning it’s added during manufacturing rather than occurring naturally. Common fortified products include milk, some plant-based milks, orange juice, and breakfast cereals.

Practical tip: fortification amounts vary significantly by brand and product, so check the Nutrition Facts label rather than assuming all versions of a product (like all plant milks) contain the same amount.

4. Include Vitamin D3 Sources in Your Diet

Natural animal sources (such as fatty fish and egg yolk) contain only vitamin D3, whereas fortified foods and plant sources (such as mushrooms treated with UV light) contain only vitamin D2. If you want to know whether one is better absorbed by your body than the other, check out our [comparison of vitamin D2 and D3].

5. Look at Your Overall Diet, Not Just One Food

No food by itself is going to be able to resolve the issue of insufficient intake of Vitamin D because even the most effective food sources do not contain enough to fulfill the full need on a regular basis. It is better to have a variety of foods in the diet that have vitamin D on a constant basis rather than one “miracle food.”

6. Consider a Vitamin D Supplement When Appropriate

However, for a significant number of individuals, sufficient intake of vitamins from food and sun exposure alone cannot guarantee that their vitamin D levels are high. These include people who have very little exposure to sun, those with dark skin, obesity, malabsorption issues, and people living in places where there is very little sunshine throughout the year.

When you reach this point, our [vitamin D3 buying guide] will help you with the dosing, the form, and the quality of the supplement. One important thing to note at this point is that more is not better. This means that taking high doses of supplements without the advice of your doctor can pose some risks to your health (see safety below).

7. Talk With a Healthcare Professional If You May Be Low

I think that if you have risk factors or if you keep having symptoms that worry you or if you never had your vitamin D checked you should talk to a doctor instead of guessing. A blood test is the way to really find out your vitamin D level. Trying to eat vitamin D foods or get more sun is a good idea but it does not replace the need to know the exact number if you truly worry. So if you have a reason, for concern a doctor can help you get a clear answer.

Foods That Are High in Vitamin D

(Values approximate, based on USDA FoodData Central and U.S. Dietary Guidelines food composition data; actual content varies by specific product, preparation, and source.)

Does Sunlight Really Increase Vitamin D?

Yes, genuinely — UVB exposure triggers a real synthesis process in your skin, and it’s historically been the primary source of vitamin D for most people. A few important caveats worth understanding:

• Window glass blocks UVB. Sitting near a sunny window doesn’t produce vitamin D the way direct outdoor exposure does, since standard glass filters out most UVB radiation.
• More sun isn’t proportionally better. Your skin has a natural ceiling on how much vitamin D it will produce from a single exposure; prolonging sun time well past that point doesn’t meaningfully increase production, but it does increase skin damage risk.
• Sunburn is never a strategy. Deliberately allowing your skin to burn in pursuit of vitamin D doesn’t work that way biologically, and it meaningfully raises skin cancer risk over time. This is a genuine safety point, not just a caution slide — the American Academy of Dermatology and major cancer organizations specifically advise against using intentional sun exposure to manage vitamin D status.

If you live somewhere with limited sun for much of the year, or you have reasons to limit direct sun exposure (skin cancer history, photosensitive medication, personal preference), that’s a completely reasonable position — it just means food, fortified products, and potentially supplementation become more important parts of your plan.

Why Your Vitamin D May Stay Low

If you’ve made some of these changes and are still wondering why your levels don’t seem to budge, a few common contributing factors are worth knowing about (not as a diagnosis, but as context):

• Limited sun exposure due to climate, season, indoor work, or lifestyle
• Living at a higher latitude, particularly in winter
• Darker skin pigmentation, which reduces synthesis efficiency
• Older age, which reduces both skin synthesis and kidney conversion
• A diet that includes little dietary vitamin D
• Digestive or absorption conditions (Crohn’s disease, celiac disease, cystic fibrosis, history of bariatric surgery)
• Obesity, since vitamin D is fat-soluble and can be sequestered in fat tissue
• Certain medications that affect vitamin D metabolism

If several of these apply to you, food and sun changes alone may genuinely not be enough, that’s a reasonable point to loop in a healthcare provider rather than a personal failure of effort.

How Long Does It Take to Increase Vitamin D?

There’s no fixed universal timeline, and be skeptical of anything promising a specific number of days. The realistic answer depends on:

• How low your starting level was
• How consistently you’re increasing dietary intake or sun exposure
• Whether you’re also using a supplement, and at what dose
• Individual factors like age, weight, and absorption ability

For people using supplementation to correct a confirmed deficiency, clinicians typically retest after roughly 8–12 weeks of consistent use to check progress, which gives a rough sense of the timeline involved, though that’s specific to supplementation under medical guidance rather than diet and sun exposure alone, which tend to work more gradually.

Should You Get Your Vitamin D Level Tested?

In order to be sure about your vitamin D levels, there is no choice but to get tested using 25-hydroxyvitamin D [25(OH)D] tests because symptoms do not give any evidence to prove this condition, as most symptoms related to low vitamin D (such as fatigue and low mood) may occur due to many other causes, and people with confirmed low vitamin D levels lack symptoms.

Getting tested is more justified if you have several risk factors or persistent symptoms or if you just wish to see your baseline levels before deciding on whether dietary modifications or supplements are necessary. If you are wondering whether this is your case, check out our guide to [signs of vitamin D deficiency].

What About Vitamin D Supplements?

If food and sensible sun exposure aren’t realistically going to get you where you need to be, supplementation is a reasonable, well-studied next step but a few things are worth knowing before you buy anything:

• Form: vitamin D3 is generally considered more effective than D2 at raising and maintaining blood levels for most people, though both are legitimate options. See our [D2 vs. D3 comparison] for the full evidence breakdown.
• Dose: more isn’t better. The upper limit for adults is 4,000 IU/day from all sources combined, per the National Academies of Sciences, and going meaningfully above that without medical supervision isn’t supported by evidence of added benefit.
• Food vs. supplement: supplements provide a more predictable, consistent dose than food or sun exposure, which is useful if you’re specifically trying to correct a confirmed deficiency.
• Third-party testing: look for USP, NSF, or Informed Choice certification to confirm label accuracy, since supplements aren’t FDA pre-approved the way medications are.

For the full buying framework, see our [vitamin D3 buying guide].

A Simple Vitamin D Action Plan

This week, consider:

1. Check whether your current diet includes any vitamin D sources — even a rough mental inventory helps
2. Look for fortified foods you already buy (milk, plant milk, OJ, cereal) and check their labels for actual vitamin D content
3. Think honestly about how much regular outdoor time you get, and during which months
4. Review the risk factor list above and note which ones apply to you
5. If you have real concerns about deficiency several risk factors, ongoing symptoms, or you’ve simply never been tested schedule a conversation with a healthcare provider about testing
6. Don’t start a high-dose supplement “just in case” without guidance get a baseline first if you’re genuinely concerned

Common Mistakes When Trying to Increase Vitamin D

1. Assuming more sunlight is always better. Past a certain point, additional sun exposure doesn’t meaningfully increase vitamin D production, it just adds skin damage risk.
2. Relying on one food as a fix. No single food provides a complete daily solution in a realistic serving size; variety matters more than any one “superfood.”
3. Taking very high-dose supplements without testing first. Without a baseline, you can’t tell if you’re correcting an actual deficiency or just adding unnecessary intake.
4. Assuming symptoms alone prove deficiency. Fatigue and low mood have many causes testing is the only way to confirm vitamin D specifically.
5. Ignoring fortified foods. Many people overlook fortified milk, plant milk, and orange juice as meaningful, easy contributors.
6. Buying supplements based only on the IU number on the front of the bottle. Form (D2 vs. D3), delivery method, and third-party testing matter just as much as dose.
7. Assuming everyone needs the same amount. Individual needs vary by age, baseline status, body weight, and absorption ability, there’s no single right answer for everyone.

Frequently Asked Questions

Next Steps

• Want to understand whether your symptoms might actually point to deficiency? See [signs of vitamin D deficiency]
• Deciding between vitamin D forms? See our [D2 vs. D3 comparison]
• Ready to consider a supplement? See our [vitamin D3 buying guide] for how to choose dose, form, and quality

Sources

• National Institutes of Health, Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals and Consumer Fact Sheet.
• U.S. Department of Agriculture, FoodData Central.
• U.S. Dietary Guidelines for Americans 2020–2025, Food Sources of Select Nutrients.
• National Academies of Sciences, Engineering, and Medicine (Food and Nutrition Board). Dietary Reference Intakes for Calcium and Vitamin D.
• American Academy of Dermatology, guidance on sun exposure and vitamin D.

Disclaimers

Medical disclaimer: This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always talk to a qualified healthcare provider before making significant changes to your diet, sun exposure habits, or before starting any supplement.

Editorial transparency: This article was researched and written using USDA food composition data and current NIH/NASEM guidance, as cited above. It has not been reviewed by a licensed medical professional. We have not personally tested any products referenced in related ReliefWellPro content; product evaluations on this site are based on publicly available formulation data, third-party testing information, and published research rather than in-house testing.

Affiliate disclosure: Some links on ReliefWellPro may be affiliate links, meaning we may earn a commission if you make a purchase, at no additional cost to you. This does not affect our editorial evaluation of any product.