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By Meghan Novoshielski, MS, RDN
Expert Verified by Victoria Burgess, Phd, CSCS, CISSN
Reviewed by Joana Neziri, MS, NASM-CPT
Fact Checked by Kelly Uhler
Our nutrition experts rigorously evaluated various vitamin D supplements for quality, dosage accuracy, safety, effectiveness, and more. Based on our comprehensive analysis and real customer feedback, we compiled a list of the best options to meet your health needs.
Dietitian Victora Burgess and Sports Nutritionist Meghan Novoshielski explain the different types of vitamin D available on the market and breaks down which ones are best for different populations. Two seasoned health writers and an expert fact-checker review their work.
Vitamin D, a fat-soluble nutrient essential for bone health, has recently been linked to other important functions in our bodies, including supporting blood sugar management, immunity, and heart health. Despite the body’s ability to produce Vitamin D when exposed to sunlight, deficiencies have become increasingly common due to more time spent indoors and the use of sunscreen. Due to the fact that Vitamin D is fat-soluble, its absorption will depend on the body’s ability to absorb dietary fat. While Vitamin D is available in some foods, these sources are limited, increasing the risk of deficiency. Supplements can help ensure adequate intake. But how to choose? ( 1 )
To help you navigate the crowded market of Vitamin D supplements, our nutrition experts, including a registered dietitian, have reviewed and narrowed down the top options. We evaluated products based on ingredient quality, dosage, safety, and effectiveness to curate a list of the best choices. Our recommendations will help ensure you get the best Vitamin D supplement for your body’s needs.
Our editor’s choice for vitamin D supplement is Onnit Vitamin D3 Spray . This plant-based liquid supplement delivers an effective 1,000 IU dose of D3, paired with MCT oil, to aid absorption. It also includes vitamin K2 for enhanced bone health support. Read on for our full review and testing notes.
Medical disclaimer: This article is intended for educational and informational purposes only. It is not intended as a substitute for medical advice. For health advice, contact a licensed healthcare provider.
Onnit Vitamin D3 Spray stands out for its plant-based ingredients, ease of use, and safe and effective dosing.
Onnit’s vitamin D3 spray provides a healthy dose of vitamin D in an easy-to-take format that caters to various lifestyle needs.
A five-spray dose delivers 1,000 IU of vitamin D3, enough to prevent deficiency without the risks associated with excessive mega-doses. ( 1 ) D3 is the most effective form of vitamin D, raising blood levels quicker than the other forms. ( 2 )
Onnit sources its vitamin D3 from plants, specifically lichens, a unique organism composed of fungus and algae. So, this spray is suitable for vegans, vegetarians, and those avoiding animal-based products. Additionally, it’s gluten- and soy-free.
Onnit’s spray format is also ideal for those who dislike taking pills; studies showing that liquid forms are as effective as other forms in raising vitamin D blood levels. ( 3 )
Other key ingredients include 150 mcg of vitamin K2, Medium-Chain Triglyceride (MCT) oil, vitamin E, natural flavors, and stevia. All are naturally derived, making this product free from artificial additives.
Some studies suggest that vitamin D and K2 work together to support bone health, with vitamin D aiding calcium absorption and K2 directing calcium into bones. Clinical trials have actually observed greater improvements in bone mineral density when these nutrients are taken together. ( 4 , 5 ) That said, more research is needed to determine optimal dosages and uses.
It’s also worth noting that vitamin K can affect blood clotting and can interact poorly with certain blood thinners. ( 6 ) Anyone taking those medications should talk with their doctor before using Onnit Vitamin D3 spray.
The inclusion of MCT oil may enhance the absorption of vitamins D and K, both fat-soluble, though there’s no evidence that oil-based supplements are superior to powder-based ones. ( 5 ) Since this spray’s MCT oil comes from coconuts, it isn’t a safe product for people with tree nut allergies.
Vitamin E serves as an antioxidant, protecting this oil-based formula from rancidity. Finally, natural flavorings and stevia deliver two well-rated flavors: grapefruit and passionfruit.
Our team appreciates that Onnit’s spray is third-party tested and certified by Informed Choice Sport and the Banned Substances Control Group. These certifications ensure that you’re getting what the label says and no additional contaminants or substances banned by athletic organizations.
The main downside of Onnit, however, is the cost. A thirty-day supply is about twenty-five dollars, making this the most expensive item on our list. Nonetheless, our team believes this product offers a lot of value.
Onnit’s Vitamin D3 spray has 76 reviews on Amazon. Many reviewers enjoy the taste and convenience the product offers.
Verified customer Ms. Wells shares that it’s “a legit easy lifestyle incorporation.” At the same time, reviewer AA describes this product as “easy to digest with no aftertaste, and I love how simple it is to get my daily intake.”
Conversely, some customers feel the dosage is too low, and the bottle doesn’t last as long as expected.
Nutricost D3 combines high-quality ingredients with convenience and affordability, offering a safe and effective dose of vitamin D3 in an easy-to-swallow softgel capsule.
Nutricost combines ingredient quality and convenience with affordable pricing to offer great value. Each Nutricost softgel provides 2,000 IU of Vitamin D3, sufficient to boost your vitamin D levels into healthy ranges without being a mega-dose. This allows flexibility in adjusting your intake without exceeding the established safe upper limit of 4,000 IU daily.
The list of other ingredients is short: safflower oil, which may enhance vitamin D absorption, and glycerin, gelatin, and water, which make up the softgel. By avoiding extra additives, this product is free of major allergens, including gluten; it’s also non-GMO.
Nutricost further ensures ingredient quality through its production processes. This product is made in an FDA, GMP-compliant facility and is third-party tested for potency and safety.
And, the softgels are small and easy to swallow, making them ideal for individuals who struggle with larger pills. Each bottle contains 240 capsules, providing a supply that lasts over six months. At just $0.06 per capsule, Nutricost ties as the most affordable vitamin D3 product on our list.
Over one hundred Amazon customers have rated Nutricost’s Vitamin D3 supplement. They share a lot of positive feedback on how easy the softgels are to swallow as well how satisfied they are with the value and packaging.
“These are a great compromise between gummies and harder to swallow dry pills. Gummies tend to be much higher cost and these are a very easy to swallow capsule with great value.”
V.Pack, Verified Amazon Customer
Riverdancer, another satisfied customer, shares, “Because I take one of these every day, getting a bottle of 240 means I will be set for several months. These are set in an oil-based tablet for better absorption, and they are small and are swallowed easily, and they don’t have any noticeable flavor. I take other Nutricost vitamins, and these are right in line with those as far as being affordable vitamins.”
Some customers shared that they received melted products. Since softgels can be sensitive to high temperatures, other customers recommended keeping this product refrigerated.
Transparent Labs D3+K2 is a high-dose supplement designed for convenience and effectiveness, particularly for men’s health. The combination of D3 and K2 helps strengthen bones and protect heart health .
Transparent Labs D3+K2 is another product that combines the benefits of two nutrients in one convenient supplement. It pairs a high dose of vitamin D (5000 IU) with vitamin K2, which has superior bioavailability to other forms of vitamin K.
In addition to promoting bone health, vitamin K2 may improve heart health by reducing arterial stiffness, resulting in healthier, more flexible blood vessels—an important benefit for men who have a higher risk of heart disease. ( 11 , 12 )
If you need help remembering to take supplements, a high-dose option like this allows you to boost vitamin D intake by taking it weekly versus daily. That said, the 5,000 IU in each Transparent Labs capsule exceeds the safe upper limit of 4,000 IU daily, so if you intend to take this daily, consulting a doctor before use is a must. ( 1 )
Our team especially likes that this formulation is simple, using only naturally derived ingredients without artificial additives, sweeteners, dyes, or flavors. The Transparent Labs’ vitamin D3 comes from plant-based sources (lichen), though the company lists that the product is not vegan in their FAQ section.
We also love that Transparent Labs participates in third-party testing, ensuring their products are safe and accurately potent. You can find all third-party testing results on the Transparent Labs website.
At $0.50 per softgel, the Transparent Labs D3+K2 supplement offers a good balance between cost and quality. Each supplement has a 30-day return policy.
With science-backed doses of vitamin D3 and K2, Legion effectively supports women’s bone health.
Legion provides women with vitamin D, without unwanted additives.
According to a 2023 analysis, women are more likely to have vitamin D deficiencies, which can affect their bones and overall health. ( 8 ) Compounding this, as women approach menopause, their estrogen levels drop, leading to reduced calcium absorption and an increased risk of osteoporosis. ( 9 )
Legion Vitamin D+K addresses these concerns by offering 2000 IU of vitamin D3 per capsule. This dose of vitamin D can effectively replenish vitamin D levels, which is crucial to calcium absorption and bone health. ( 7 )
Additionally, this product includes 280 micrograms (mcg) of vitamin K (K1 and K2), which, when combined with vitamin D, may increase bone mineral density more than each vitamin alone. ( 4 , 5 , 10 , 6 ) However, vitamin K can affect blood clotting and interact with blood-thinning medications. If you take medications like this, check with your doctor before starting Legion Vitamin D+K. ( 6 )
Legion avoids unnecessary additives in its products. Its formula excludes artificial sweeteners, dyes, flavors, fillers, gluten, soy, and dairy. Plus, it’s calorie-free, so it can meet various dietary needs.
However, while a veggie-based capsule encases the nutrients, this product’s vitamin D3 comes from lanolin (sheep’s wool), making it not vegan-friendly.
Another feature of this product is its transparency. Legion’s vitamin D+K is NSF-certified, and its website displays the Certificates of Analysis, verifying potency and safety.
While it’s comparatively expensive at $0.67 per serving, Legion offers a “no return necessary” money-back guarantee, demonstrating confidence in their product.
Finally, each bottle of Legion Vitamin D+K provides 60 servings, and the single capsule serving is easy to swallow, adding to its convenience.
Legion vitamin D+K has earned 73 reviews on Amazon. Customers are happy with the quality of the product, its effect on their health, and the convenience of getting vitamin D and vitamin K in one easy-to-swallow gel cap.
“This supplement really helps me to fill the gaps in my nutrition and make sure that I’m getting the right amount of vitamins D and K. I’ve also found that since the sun isn’t always out here in Canada, supplementing with vitamin D helps a lot with my mood and immune health.”
Adam P., Verified Amazon Customer
Eric G. also thinks it’s “a great price for what you get,” noting that he likes “how Legion combined D+K to create one pill for both.”
However, other customers shared negative feedback on information they thought needed to be added to the bottle label, including the Good Manufacturing Practices (GMP) seal.
Dave writes, “The supplement is fine, and I need both D & K, but I just wish the bottle had more specific and common supplement info listed on it.”
A customer with the username MJA also questioned the dosing of vitamin K, writing, “Most of us receive more than enough vitamin K1 from our daily diets, so the inclusion of K1 really isn’t needed.”
Sports Research Vitamin D3 Extra Strength includes MCT oil to enhance the absorption of vitamin D3. It’s third-party tested and free of common allergies.
Sports Research provides a high-dose supplement to support people with increased vitamin D needs, including athletes, and verifies its product quality through multiple certifications.
Athletes often have higher nutritional needs to meet the demands of intense physical activity. Recent studies show that many athletes are vitamin D deficient, suggesting they are not getting enough in their diet. Low vitamin D levels could negatively impact muscle strength and endurance and increase the risk of injury and fractures. ( 14 )
While the standard recommendation for vitamin D intake is 600 to 4,000 IU daily for adults, a 2021 meta-analysis found athletes may need more like 2,000 to 6,000 IU daily to maintain healthy vitamin D levels. ( 14 )
Sports Research Vitamin D3 Extra Strength provides 5,000 IU of vitamin D in a single softgel dose, falling within this updated range. Note that this is above the recommended safe maximum intake established by the NIH, so you’ll want to discuss taking this vitamin with your doctor. ( 1 )
Sports Research conducts third-party testing to ensure consistency and quality and adds MCT coconut oil to their softgels, which may improve vitamin D absorption. The product is also gluten-free, soy-free, dairy-free, and certified non-GMO, making it suitable for many dietary preferences. However, Sports Research sources its vitamin D from lanolin (sheep’s wool), and the softgel contains bovine (cow) gelatin, so it’s off the table for people following a plant-based lifestyle.
One of this supplement’s best features is its affordability: It costs only $0.06 per dose. And, each bottle contains 360 softgels, ensuring a long-lasting supply.
Sports Nutrition Vit D3 Extra Strength is an established popular product, earning over 59,000 Amazon reviews. Customers are happy with this product’s quality, effective dose, and ease of swallowing. They also appreciate that each bottle contains many doses, so they don’t have to order as often.
Verified reviewer AJ Clearwater shared how this product delivered results for him, writing, “In May my blood test showed lower Vit D results 26.0 ng/mL, ordered this and started taking it in June. My December blood test showed my Vit D results at 58.60 ng/mL, normal range is 30-100 ng/mL. So this definitely works. I work from home in my basement office, so I’ll keep using this daily. I’ll probably be able to take it once every 2 days during the summer months.”
“I like these so much that I purchased a year’s supply! Sometimes vitamins/supplements are huge horse pills, but these are small and easy to swallow. They don’t have any weird aftertaste either.”
Erin M., Verified Amazon Customer
Among the few negative comments were complaints about the product’s smell and issues with receiving expired products from Amazon.
Ora Sol Food is a certified organic product, meaning an unbiased party has validated that all ingredients meet federal organic standards for how they are grown, raised, and produced. This product is also plant-based and third-party tested for quality and safety.
Ora provides certified organic vitamin D supplement options sourced from plants.
Obtaining organic certification means that a certifying body verifies all the ingredients in this product are raised, grown, and produced according to federal organic standards for health and the environment.
Ora offers two vitamin D supplement options: standard and high potency. The standard option provides 2,000 IU of vitamin D3 in each dose, while the high potency option combines 5,000 IU of vitamin D3 with 100 micrograms of vitamin K2.
Both doses will help achieve healthy vitamin D levels, while the high potency option may be extra beneficial for people working to correct nutritional deficiencies with their doctor’s supervision. ( 1 )
Furthermore, vitamin D and K2 potentially work better together to improve bone strength, making this appealing to people seeking bone health support. ( 4 , 5 , 10 , 6 )
Both options are entirely plant-based, sourcing vitamin D3 from lichen and vitamin K from chickpeas. They’re also free from dairy, gluten, soy, GMOs, tree nuts, added sugars, artificial colors, flavors, sweeteners, and preservatives.
Ora also third-party tests each batch of its products before they reach the shelves, checking for potency and the presence of heavy metals, microbes, allergens, and pesticides. You can find all the test results on Ora’s website.
Rather than taking a pill or gummy, this product comes in a slightly sweet chewable tablet. The sweetness comes from the inclusion of sugar alcohols—erythritol and xylitol–which can cause digestive upset in sensitive people. ( 15 )
Every bottle of Ora Sol Food contains thirty tablets, which will last you a month. However, at $0.67 per serving for the lower dose and $0.83 for the higher dose, this option is more expensive than others on the market.
Amazon customers like Ora’s vitamin D products, and they are rated highly for ingredient quality and effectiveness.
“It’s hard for me to find the right vitamins that are non-GMO, organic, and vegan. These go down easy and help me feel fantastic!”
Another customer, J. Alberry calls these “the perfect vitD…easy to swallow. Feel strong and healthy. Glad it’s 100% organic.”
However, some customers complain that this product didn’t deliver results cost-effectively. One reviewer shared, “Unfortunately, this product did not improve lab results…Taking two a day may improve chances, but then it is not cost-effective.”
Sunergetic Vitamin D3 Gummies offer an effective dose of 2,000 IU of D3 in each tasty serving.
Sunergetic’s gummies offer a tasty alternative to pills for meeting your vitamin D needs. Two gummies provide 2000 IU, an effective dose for raising low vitamin D levels. ( 7 ) If you already have sufficient levels, you can reduce to one gummy daily, extending the bottle’s life and saving some money along the way.
Each Sunergetic bottle contains a blend of three tropical flavors: strawberry, peach, and mango. Supplements that taste good may help people stick with a routine better. These gummies also don’t contain artificial dyes or flavors and use pectin instead of gelatin, making them vegan and vegetarian-friendly. They’re also gluten-free.
We don’t love that the first ingredient on Sunergetic’s nutrition label is glucose syrup, which adds fifteen calories and three grams of sugar to each serving. Additionally, at $0.57 per serving, these gummies are more expensive than many other options on the market.
Another consideration before you buy these gummies is that gummies (in general) degrade faster than capsules or tablets, which means they lose their potency over time. And, Sunergetic does not conduct third-party testing, so the gummies’ specific vitamin D content is not verified to begin with.
Despite these drawbacks, these gummies can be beneficial if you struggle with other supplement forms. Note: they do contain tree nut allergens.
Ddrops Liquid Vitamin D3 Booster provides 150% of kids’ daily vitamin D needs in a format that goes undetected in various foods and beverages, helping improve the nutrition intake of even the pickiest eaters.
It’s no secret getting kids to eat enough healthy foods can be tricky. However, deficiencies in critical nutrients, like vitamin D, can impact their growth and increase their chances of getting sick. ( 1 ) Ddrops Kids Vitamin D Booster helps cover some of these nutritional bases, providing ample amounts of vitamin D3 in a format kids won’t mind taking.
Ddrops are designed for children one year and older. The recommended dose is one drop, which can be taken directly or added to foods or drinks where kids won’t be able to tell it’s there. One drop provides the American Academy of Pediatrics (AAP) recommended daily amount of 600 IU of vitamin D3. ( 13 )
While these features make this product convenient, bear in mind it can be challenging to get the drop out of the bottle correctly and consistently. You’ll want to be cautious to avoid dispensing too much. To ensure full dosage, it’s important for the child to drink all liquid included in the glass, even when mixing with water.
Ddrops keeps its formula simple, including only coconut oil to improve the absorption of fat-soluble vitamin D. Parents will like that this product is free from common allergens like wheat, soy, dairy, corn, and nuts, and contains no sugar or artificial flavors, preservatives, or dyes. However, the D3 in this product is sourced from lanolin (sheep’s wool), so it’s not suitable for vegans.
Parents will also feel reassured that this product is NSF-certified, meaning a third party tests and monitors it for potency and purity from heavy metals and other contaminants.
Each bottle provides 100 one-drop doses, so it will last. Plus at $0.13 per dose, it’s more affordable than many other products.
Almost three thousand Amazon customers have reviewed Ddrops Kids Vitamin D Booster. Customers particularly like the ingredient quality, value, and how easy it is to add to kids’ diets.
“I purchased these drops to use with my 2 and 3 year old children. They have absolutely no taste which makes it easy to sneak into any beverage or moist food.”
Tracy T., Verified Amazon Customer
Chelsie, another customer, also praises the convenience of Ddrops, writing “Have administered this in water, directly on tongue, really any way my toddler doesn’t mind, it’s virtually tasteless!”
However a common complaint is that it can be difficult to get the drop to come out correctly, especially as you get near the end of the bottle. According to Peter L., “I like its simple ingredients. It comes out quickly so be careful. But it takes forever to come out when it gets low so we never completely finished a bottle.”
Gnarly’s 1,000 IU baseline dose allows flexibility to adjust your amounts up or down in safe increments based on your needs. The D3 in Gnarly’s product comes from Vitashine(™), a plant-based lichen source recognized by Vegan and Vegetarian Societies.
Gnarly Baseline Vitamin D3 can help people following a vegan diet avoid vitamin D deficiency.
Vitamin D3 is the most bioavailable form of vitamin D, but it’s mostly found in animal products, making it difficult to obtain on a vegan diet. ( 2 ) Gnarly Baseline offers 1,000 IU of vitamin D3 in each vegan, one-capsule dose, meeting the established recommended daily intake for adults (600 IU). ( 1 ) It also allows flexibility to increase the dose in reasonable increments per your personal health needs by simply taking more capsules. The body takes a few weeks to absorb vitamin D, so ensuring a consistent dose will ensure it happens as soon as possible.
Gnarly uses a branded version of vitamin D3 called Vitashine(™), which comes from lichens, a combination plant-based organism of algae and fungus. When exposed to UV light, lichen produces vitamin D3, which can then be extracted and used in supplements.
The capsule content itself is made from cellulose, water, and rice bran. With no other ingredients, it’s a uniquely clean-label product. However, there’s no indication this product is third-party tested, verifying the product contents, which you’ll want to consider.
At $0.22 per serving for a 60-day supply, these capsules are the most affordable plant-based option on our list.
We’re committed to providing thorough and trustworthy reviews for vitamin D supplements to help you make informed decisions. Our team of nutrition experts rigorously tests and researches each product, evaluating factors such as efficacy, safety, ingredient quality, and value.
You can read our full supplements testing methodology here to understand our comprehensive approach.
Evaluating dietary supplements efficacy ensures consumers can trust the product to meet their wellness goals. This involves verifying if they can genuinely deliver the claimed health benefits, supported by scientific evidence. Here’s what we look for when analyzing efficacy:
Understanding safety and side effects of each supplement choice helps you make a fully informed choice on which option is best suited for your health. Here’s what we assess when reviewing safety and side effects:
Value encompasses the cost in relation to the potential benefits. There are many supplements you could take, considering value provides you with the information you need to prioritize your choices. This is what we consider when discussing a product’s value:
The best supplement companies take customer satisfaction seriously, knowing their products must fit customers’ lifestyles. Assessing customer experiences helps identify trustworthy options for your health journey. We look for the following to assess a company’s customer experience:
Vitamin D acts as both a nutrient and a hormone, influencing health in the following ways:
Vitamin D helps your body absorb and use calcium to build strong bones, preventing rickets in children and protecting older adults from osteoporosis. ( 1 )
Vitamin D helps shut down inflammatory responses in your body, potentially protecting you from chronic inflammatory diseases. ( 16 )
Vitamin D directs immune system activities and helps healthy immune cells grow. Adequate intake could help you fight off viruses,infections and autoimmune diseases. ( 17 )
Vitamin D promotes insulin sensitivity, helping your cells uptake and metabolize glucose in your blood. ( 18 )
There are three main ways to get vitamin D: sun exposure, food, and supplements. ( 1 )
Sunlight is the simplest way to obtain vitamin D. Exposing your skin to UV rays triggers the production of pre-vitamin D compounds, which your liver and kidneys then convert into the active form of vitamin D, called calcitriol.
Conversion rates vary between people, but experts suggest five to thirty minutes of daily sun exposure without sunscreen is enough to achieve healthy vitamin D levels.
However, the American Academy of Dermatology (AAD) warns that exposure to UV rays increases skin cancer risk, so they recommend getting vitamin D from other sources. ( 19 )
Only a few foods naturally contain vitamin D, but many others are fortified with this nutrient to help people meet recommended amounts. These include:
While eating more of these foods can boost vitamin D intake, most people struggle to get enough of this nutrient from their diet alone. Data from the 2015-2016 National Health and Nutrition Examination Survey (NHANES) found that over 90% of men, women, and children did not get enough vitamin D from foods and beverages to meet recommended intake. ( 1 )
Supplements can help bridge the gap between vitamin D intake and recommended amounts. According to the same NHANES data, people taking vitamin D supplements consumed three times more daily than those only getting vitamin D from foods and beverages. Since the body absorbs vitamin D differently among each person, its important to ensure you are receiving enough to achieve the benefits you are looking for.
Two forms of vitamin D are available through supplementation: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both are effective at raising blood levels of vitamin D, though D3 appears to be more effective and efficient. ( 2 )
Producers usually source Vitamin D3 from animals through fish oil or lanolin (an oil extracted from sheep wool). However, some producers can make vitamin D3 from plants, like lichen and algae, offering good options for people following a vegan or vegetarian diet.
Multiple formats are available, including capsules, gummies, liquids, and chewables. All can effectively raise vitamin D levels in the blood, allowing you to tailor your supplement plan to your preferences. ( 3 , 20 )
Vitamin D supplements help people meet daily requirements without harmful UV exposure. While vitamin D is known to protect bone health, researchers are exploring other potential benefits, such as cancer prevention and diabetes management.
So far, the results are mixed. Most studies show minimal to no effects of vitamin D supplementation beyond bone health. However, many study participants already had healthy vitamin D levels (50 nmol/L). In contrast, participant groups with low vitamin D levels experienced modest benefits from supplementation. Here’s some of what we know. ( 5 , 21 , 22 , 23 )
Our bones stay strong through constant turnover, breaking down old material and rebuilding with new. Calcium and phosphorus are essential for this process; vitamin D helps your body absorb and use them efficiently. Low levels of any of these nutrients weaken bones, especially in children and older adults .
Children need enough vitamin D to support their rapid growth; deficiencies cause rickets, leading to weak bones and delayed growth. As we age, vitamin D absorption is reduced, causing gradual bone loss and increasing the risk of osteoporosis.
Vitamin D supplements help these at-risk individuals meet their needs and correct deficiencies. ( 1 ) For even better results, pair them with calcium supplements. ( 5 )
Beyond bone health, researchers have discovered that cells throughout the body have vitamin D receptors, sparking interest in its role in managing conditions like cancer, diabetes, and cardiovascular disease.
However, extensive studies involving over 30,000 participants found no benefits of vitamin D supplementation for cancer, cardiac events, or type 2 diabetes in people with adequate levels (>50 nmol/l). On the other hand, those with vitamin D deficiencies did see modest delays in type 2 diabetes onset with supplementation. ( 21 )
Additionally, analysis from a clinical trial review suggests vitamin D supplementation may help reduce cancer-related deaths, but high dropout rates and biases make these findings unclear. ( 22 )
Ultimately, more research is needed in each of these areas to understand the role of vitamin D supplementation in overall health and specifically for certain people, like those with vitamin D deficiency.
Vitamin D influences the brain , specifically how it regulates mood, and observational studies have linked low levels to depression. However, clinical studies have consistently found that vitamin D supplementation, regardless of dose or duration, does not help manage depression. ( 1 )
Interest in vitamin D’s role in immune health increased during the COVID-19 pandemic. Vitamin D supports immune function and cell growth, and studies have linked low levels with higher viral infection risks. ( 23 )
Furthermore, supplementing with vitamin D may offer protection against infections. A 2021 meta-analysis found that daily doses of 400 to 1000 IU over 12 months slightly reduced the risk of contracting an acute respiratory illness. ( 23 )
Interestingly, unlike the other studies, this protective effect was observed regardless of whether individuals had adequate or low vitamin D levels. Nonetheless, further research is needed to understand these potential benefits fully.
Vitamin D supplementation will benefit people with low vitamin D levels the most. Your doctor can perform a blood test to assess your levels. ( 5 )
According to the Institute of Medicine (IOM), blood levels at or above 50 nmol/L are generally considered adequate. Levels between 30 nmol/L and <50 nmol/L are deemed insufficient, and below 30 are considered deficient. ( 1 )
However, these tests aren’t perfect. While 50 nmol/L is considered adequate for bone health, researchers still don’t know what levels are associated with optimal overall health. Depending on your blood levels, there is a large range of supplement dose that is recommended, so ensuring you are exploring those ranges to bring you up to an adequate level is ideal.
Furthermore, certain factors increase a person’s needs and risks of vitamin D deficiency. Discussing these risks and any symptoms with your doctor, alongside blood test results, can help determine if a vitamin D supplement could benefit you.
There are a few factors that can make you more likely to experience vitamin D deficiency, including:
Seasonal changes, limited outdoor time, consistent sunscreen use (even as little as SPF 8), or skin-covering clothing can reduce sun exposure and vitamin D synthesis. ( 1 , 5 )
Darker skin has higher melanin content, which decreases the skin’s ability to produce vitamin D from sunlight. ( 1 , 5 )
Older adults have a reduced capacity to synthesize vitamin D in their skin. ( 1 , 5 )
Poor consumption of vitamin D-rich foods and primarily vegan or vegetarian diets can lead to deficiency. ( 1 , 5 )
Obesity can sequester vitamin D in fat tissue, making it less available to the body. ( 1 , 5 )
Conditions like Crohn’s disease, celiac disease, and cystic fibrosis impair nutrient absorption, including vitamin D. ( 1 , 5 )
Chronic kidney disease and liver disease affect the conversion of vitamin D to its active form. ( 1 , 5 )
Certain drugs, such as anticonvulsants and glucocorticoids can interfere with vitamin D metabolism. ( 1 , 5 )
Exclusively breastfed infants may be at risk if their mothers have low vitamin D levels, as breast milk contains low amounts. ( 1 , 5 )
If you’re wondering whether or not you have a vitamin D deficiency, you may want to assess what your symptoms are. Symptoms of vitamin D deficiency include: ( 1 , 5 )
According to the National Institute of Health (NIH), men and women aged 1-70 should aim for 600 IU (15 mcg) of vitamin D daily, while adults over 70 should aim for 800 IU (20 mcg). If you are deficient in vitamin D, your doctor may recommend a higher dosage until your levels normalize. ( 1 , 5 )
Be cautious, as excessive vitamin D can be toxic. The tolerable upper limit established by the NIH is 4,000 IU daily, though up to 10,000 IU daily is generally considered safe. Work with your doctor to determine the right amount of vitamin D for your medical conditions and health needs. ( 1 , 5 )
As is the case with most supplements, there is such things as too much vitamin D. Excess vitamin D can lead to calcium buildup in the body, causing symptoms like nausea, vomiting, muscle weakness, pain, appetite loss, excessive thirst and urination, and kidney stones. ( 1 , 5 )
Vitamin D supplements can also negatively interact with medications. As a fat-soluble nutrient, it requires fats for absorption and can interact with lipid-affecting drugs like orlistat and statins. These medications may limit vitamin D absorption, while vitamin D may reduce their potency by competing with their metabolism. ( 1 , 5 )
Additionally, steroids and diuretics can affect calcium levels, leading to disturbances in vitamin D status. Many vitamin D supplements include other nutrients, such as vitamin K, which interacts with blood thinners like warfarin. Always consult your doctor before taking high doses of vitamin D. ( 1 , 5 )
Studies show that supplements containing either vitamin D2 or D3 can effectively boost blood levels of vitamin D; however, D3 appears to be the most effective. ( 2 )
There are a lot of options when it comes to choosing the supplement that’s best for you. Our team always recommends considering brands that conduct third-party testing. This additional testing ensures purity, potency, and safety from contaminants like heavy metals, microbes, and pesticides.
Vitamin D supplements come in various formats, including capsules, liquids, and gummies. All can effectively improve your vitamin D status. Choose an option that you can consistently include in your daily routine and that fits your nutritional and budget requirements.
Most treatment goals aim to improve vitamin D status within three months; however, supplements can begin to increase vitamin D levels in a few weeks. ( 1 )
Excess vitamin D can be toxic. Vitamin D toxicity will lead to an imbalance in calcium and phosphorus, affecting bone health, and increasing the risk of kidney stones. Symptoms include pain and nausea. ( 1 )
Vitamin D can also interact with lipid-lowering medications and steroids. Always discuss any supplementation with your doctor. ( 1 )
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any diseases.
Victoria Burgess, Ph.D., CSCS, CISSN
Victoria Burgess earned her Ph.D. in Health and Human Performance from Concordia University Chicago and holds her NSCA CSCS and Certified Sports Nutritionist (CISSN). She is an adjunct professor in the Human Performance and Nutrition department at Concordia University Chicago & Parker University, where she teaches undergraduate, graduate, and doctoral-level courses.
Joana Neziri, M.S., NASM CPT
Joana is a writer, editor, and content strategist focusing on nutrition, fitness, and all things health. After earning a master’s degree in business from the University of North Florida, she began a career in research and digital marketing.
Lily is a Brooklyn-based writer and editor with over seven years of experience in health media. As a former Fitness Coach, Lily’s editorial prowess has largely focused on fitness, nutrition, and weight management. She has also spent a fair share of time in testing labs, analyzing everything from protein powders to yoga mats. Her work has appeared in Verywell Fit, Verywell Mind, Health, and more.
Kelly has a multifaceted background in elder care, health care, and copywriting. She has worked for organizations such as A Place For Mom and Homecare.com, which gave her the opportunity to work closely with families, providing reliable information to help them make informed decisions about their loved one’s health, safety, and quality of life.
Meghan is a Registered Dietitian Nutritionist (RDN) with over 15 years of experience in the nutrition field. She holds a Master’s in Nutrition Science and Policy from Tufts University and has helped create evidence-based, highly effective products for brands like Nutrisystem and Wawa to improve people’s health. As an experienced health writer, Meghan is passionate about motivating people to pursue their healthiest lives through trustworthy, practical, and engaging nutrition content. These days her health and fitness goals are all about staying strong and active to keep up with her three young and very energetic children.
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