Vitamin D is commonly remembered as the vitamin we get from sun exposure.
After decades of research, scientists are still unable to pin down the true nature of this vitamin and what it can do for health, although we know Vitamin D helps the body absorb calcium.
On the one hand, vitamin D has gained a reputation in the last few years as a “wonder” vitamin with powers over cancer, heart attack, Alzheimer’s disease, and other serious conditions. While the science on the non-skeletal benefits of vitamin D is still being sorted you, what is known is that your body can’t synthesize vitamin D naturally unless you are exposed to sunlight—so for people who live in cold or sunless climates (especially if you have darker skin), taking a vitamin D supplement is a very smart call.
Here, we’ve ranked the top vitamin D supplements on the market for you. After the rankings, we’ll break down how vitamin D works and how it can benefit you.
Rankings
1. TransparentLabs RawSeries Vitamin D3
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If the weather is overcast or you’re working long hours indoors, you’re not getting enough sunshine—which means you’re lowering your immunities and reducing your strength and performance while increasing your risks of cancer and heart disease.
Yes, it’s that serious…
Which is why we love TransparentLabs Vitamin D3. Could there be an easier way to stay happy and healthy?
RawSeries Vitamin D3 delivers 5,000 IU of active vitamin D—enough to boost your strength, testosterone, mood, and bone density regardless of the storms outside (or in your daily life).
No artificial sweeteners. No artificial coloring. Gluten-free and non-GMO. No artificial preservatives.
Each capsule packs your daily vitamin D in a gelatin softgel (vegans be aware) with safflower, glycerin, water, and sunflower oil. The plant-based oil carriers ensure you’ll get full absorption. And with 120 capsules in each bottle, you’re good for a full 3 months.
The all-around Vitamin D winner of 2020.
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2. Nordic Naturals Vitamin D3
Although Nordic Naturals is more famous for their fish oil products, they’ve branched out to vitamin D as well. It makes perfect sense, considering that vitamin D is rather scarce in Scandinavia.
In any case, Nordic Naturals D3 provides a concentrated vitamin D source alongside some of its trademark healthy oils. Each softgel provides 5000 IU of vitamin D3, dissolved in olive oil and the omega-9 fatty acid oleic acid. These are hypothesized to have heart health benefits.
In terms of purity, Nordic Naturals scores tremendously well. Independent lab testing shows that each softgel contains 1010 IU of vitamin D, within one percent of its label-stated amount.
The softgels are flavored with natural orange extract and preserved with rosemary extract, which removes the need for a synthetic preservative to keep the supplement fresh.
The only people who may not like Nordic Naturals Vitamin D3 are vegetarians and vegans (the capsule is made of gelatin, an animal product) and hardcore purists who desire as little extras in their supplements as possible. For everyone else, it’s a great choice.
3. Do Vitamins DailyD D3
Do Vitamins D3, a supplement that delivers 2500 IU of D3 per capsule, has two appealing qualities. First, unlike almost all other vitamin D supplements on the market, it’s derived from plant sources.
It’s very tough to find vitamin D3 in nature outside of animal sources (most supplements use D3 derived from sheep’s wool, as no plant makes it naturally in high qualities, with a few special exceptions: some fungi, like mushrooms and lichen, can synthesize vitamin D the same way people do, by using sunlight.
Do Vitamins D3 uses a lichen source for its vitamin D3.
As you might guess, the capsule is made from plant cellulose. It’d be awfully silly to go to the trouble of sourcing plant-based vitamin D3 if you were going to deliver it in a gelatin capsule.
The other appealing aspect of Do Vitamins D3 is that, like its other products, it carries the LabDoor “Tested for Sport” certification.
Though the chances of contamination with banned doping agents like steroids are very low for a basic supplement like vitamin D, it’s still a nice perk if you need peace of mind.
People who compete in sports that use drug testing, like triathlons, road racing, all NCAA sports, and some bodybuilding and weightlifting divisions, can consider this as a good added value.
Supporting supplements that are tested for sport also encourages the spread of the practice, helping to stamp out the problem of contaminants in supplements.
The only drawback is that, because of this special sourcing and extra testing, the cost will be higher than average. But if plant sources or contaminant testing are important to you, it’s worth the increase in price.
4. Carlson Labs D3
Carlson Labs is a smaller company that doesn’t command nearly the market share of some of its competitors, but that does not prevent it from delivering a great product.
It’s a pretty simplistic supplement, using safflower and corn oil to dissolve the fat-soluble vitamin D3 it contains in a gelatin-based capsule that delivers 1000 IU of the vitamin.
In terms of purity, it does exceptionally well. Independent lab testing finds that it contains within two percent of its label-stated amount of vitamin D3, which is especially impressive considering that some of its competitors can’t even come within 40% of their own target.
Strictly speaking, olive oil is healthier than other plant oils like safflower oil and corn oil, but when each capsule contains such a tiny amount, being particular about this is a bit excessive.
Only the most persnickety buyer could fault Carlson Labs for using a less healthy option than olive oil. The only reason oil is present in the first place is because vitamin D3 is not soluble in water; it must be dissolved in fat instead.
5. Nutrigold Vitamin D3
Nutrigold has two vitamin D offerings; they are identical save for their dosage. One option is a 1000 IU dose delivered in bovine gelatin, and the other is 2000 IU.
Nutrigold has a strong tradition of quality ingredients for a low cost with a purist, minimalist design philosophy, and for the most part, that holds true here, too.
Independent lab testing finds that it does exceed its label-claimed amount by around ten percent, delivering 1100 IU per capsule instead of 1000 IU.
One attractive perk that speaks to Nutrigold’s commitment to purity is that, unlike some of its competitors, this supplement is not manufactured on equipment shared with allergens like soy, milk, wheat, or fish.
If you have allergies to any of these ingredients, getting Nutrigold Vitamin D3 is a good call for some peace of mind.
6. NatureWise Vitamin D3
As the number one best-seller on Amazon.com, NatureWise Vitamin D3 has some serious clout. It’s also a very serious supplement-it delivers 5000 IU of the vitamin per capsule.
This is a lot higher than the recommended daily intake (600 IU, updated from 400 IU in 2010). Still, many scientists and nutritionists advocate for much higher values, noting that exposure to direct sunlight can elicit the same blood vitamin D response as several thousand IUs per day.
If you are a believer in a higher daily intake of vitamin D, which might be a good idea for residents of northern climates in the wintertime, and especially so for those residents with darker skin, this is a great choice.
This product appeals to the minimalist, too, as the only ingredients aside from vitamin d are olive oil and the constituents of the capsule (gelatin and glycerin).
All but serious avoiders of animal products can be encouraged to see this ingredient list.
Since each bottle provides 360 capsules, and each capsule contains 5000 IU of vitamin D, it’s among the best in terms of value: the amount of vitamin D you’ll get per dollar is tremendously high.
7. Doctor’s Best Vitamin D3
The Doctor’s Best brand has a reputation for high-quality supplements with low cost and good purity. Its vitamin D offering lives up to this standard fairly well.
It comes in two different dosages, 2000 IU and 5000 IU. These give you flexibility when it comes to dosing, both from person to person (a large man needs more vitamin D than a slim woman) and throughout different times of the year.
You may want to do a lower dosage in the summer and a higher dose in the winter, for example.
It should come as no surprise that the only other ingredients are virgin olive oil, gelatin, and water. One downside to Doctor’s Best Vitamin D3 is that no independent lab testing is available to assay its purity, so you’ll have to rely on the overall reliability of the brand based on its other offerings.
Fortunately, Doctor’s Best has one of the best track records among the widely distributed low-cost brands, so odds are the dosing is accurate and there are no impurities present.
8. Now Foods Vitamin D3
As one of the mainstays of inexpensive and simple vitamins, Now Foods brand is a common sighting at local big-box retailers and pharmacies.
It’s a very simple supplement; each softgel contains 1000 IU of vitamin D dissolved in olive oil and delivered in a gelatin capsule.
Problems start to arise when we look at how Now Foods Vitamin D3 fares on independent lab testing of its contents.
Analytical tests show that the supplement actually contains 30% more vitamin D than its label states: each softgel actually delivers 1300 IU of vitamin D.
While this might sound like a good deal from a value perspective, it is not exactly a ringing endorsement of the quality control capacities at Now Foods.
This is a problem its other supplements have struggled with, too. Sometimes it’s worth it for a cheap supplement with no extra ingredients.
You’ll have to decide what’s important to you; if you want precision, look elsewhere, but Now Foods Vitamin D3 is not a bad deal as far as cost per serving of vitamin D goes.
9. Thorne Research Vitamin D-1000
On the surface, Thorne Research Vitamin D-1000 looks pretty standard. It’s a vegetarian cellulose-based vitamin D supplement that delivers 1000 IU per day.
However, it’s got one interesting and unusual ingredient: the amino acid leucine.
The choice of this particular amino acid might seem a bit puzzling at first, but Thorne Research might be ahead of the curve: a 2015 study on elderly patients found that adding leucine (as well as whey protein) to the vitamin D supplementation regimen of people at risk for sarcopenia–the loss of muscle mass associated with aging–found that leucine helped prevent this muscle loss (1).
It’s not clear how or why this works, but it might be a good idea to go for Thorne Research’s vitamin D offering if you are getting older and want to think about your muscle mass retention.
That being said, the leucine content probably needs to be higher to elicit the kind of effect seen in the scientific research study.
Beyond this, it’s a little disappointing on the purity front. Independent lab testing determined that each capsule actually contains 1300 IU of vitamin D, far above its label stated amount.
This is unusual for the smaller, usually high-quality batches from a company like Thorne Research; better purity and quality would land it higher in the rankings.
10. Vitafusion Vitamin D3 Gummies
Vitafusion is a top-seller online, probably because its gummy-based formulations appeal to people who dislike taking solid pills or capsules.
Unfortunately, its track record is a little shoddy, perhaps because it’s harder to accurately control dosing in a gummy formulation.
Each gummy provides 1000 IU of vitamin D, which is 250% of your (pre-2010) recommended daily intake.
It’s sweetened with sugar, colored with fruit extracts, and flavored with natural flavoring agents. The sugar alone probably makes it a non-starter for aggressively low-carb enthusiasts, as there are so many other good options for vitamin D that contain no sugar.
As it turns out, independent lab testing shows that the reputation of subpar manufacturing quality control holds true for Vitafusion Vitamin D3 Gummies.
Each gummy actually contains 40% more vitamin D than the label claims it does. While this is much better than containing less than advertised, it still does not speak well to the quality of the supplement.
Since it’s so much easier to get quality vitamin in an inexpensive form elsewhere, these should only be a choice if you abhor taking solid pills.
11. Nature Made Adult Chewable D3
Nature Made is a widely available brand that also sells a perfectly fine vitamin D3 supplement in capsule form. But, perhaps for the same reason, Vitafusion gummies are popular (some people do not enjoy swallowing pills), Nature Made makes a chewable form of vitamin D3 as well.
Sadly, despite its popularity, it suffers from many of the same problems as other non-capsule based vitamin D3 supplements.
Vitamin D3, being the fat-soluble molecule it is, takes a lot of extraneous ingredients to get it to a) stay in a solid chewable form, b) taste good, and c) look appealing enough to chew instead of swallow.
It is sweetened with sorbitol and sucralose, flavored with artificial flavoring agents, and colored with red dye #40, which is controversial and has a questionable safety record (though is still considered safe and okay for use in food by the United States Food and Drug Administration).
Though Nature Made Adult Chewable D3 delivers a label-claimed 1000 IU per chewable tablet, lab testing reveals how impressively inaccurate this claim is.
Each tablet actually contains 60% that much! Again, it seems that non-capsule based forms of vitamin D3 are very hard to get right.
There just aren’t enough positives to place this supplement any higher on the rankings.
Vote with your wallet and support a supplement that’s measured more accurately and pays closer attention to eliminating extraneous and unnecessary ingredients.
Who should buy vitamin D?
Nearly everyone who doesn’t live in the tropics should consider taking a vitamin D supplement at least some of the year.
The critical role of vitamin D in health, combined with the high prevalence of clinical and subclinical vitamin D deficiency across many parts of the world, should be evidence enough to seriously consider taking a vitamin D supplement.
Since the human body cannot synthesize vitamin D naturally without exposure to sunlight, if your skin doesn’t see the sun much, you are very likely to develop vitamin D deficiency.
People at risk for vitamin D deficiency can broadly be divided into three categories. First among these is people who live in northern climates, who have long, dark winters with cold temperatures.
Research shows that the prevalence of low vitamin D levels increases the further you move away from the equator, which makes sense given that you’re not likely to get much sun on your skin when it’s cold out, or when it’s only sunny for six or seven hours out of the day.
Even people who live in warm climates can be prone to vitamin D deficiency if they spend most of their time indoors and cover up with sunscreen when they are outdoors.
The second category of people at risk for vitamin D deficiency is people with darker skin. Having more melanin in your skin helps protect your body against damage from sunlight, but it also makes it harder for your body to synthesize vitamin D.
In fact, vitamin D levels are one hypothesized reason why people whose ancestors lived far from the equator have lighter skin.
In any case, if you have darker skin, and particularly if you have darker skin and you live somewhere with a cold climate, your risk of vitamin D deficiency is particularly high.
The final group that should consider vitamin D supplementation more strongly is older adults. The elderly are at a notably higher risk of vitamin D deficiency, though it’s unclear whether this is merely the result of spending more time indoors than their younger counterparts, or the result of changing hormonal biology as you get older.
Regardless, given the potential associations between low vitamin D levels and a huge range of health problems that afflict the elderly, a vitamin D supplement is a smart idea.
How we ranked
Since vitamin D is such a popular supplement, we started with dozens of potential candidates for our rankings. Our first priority was dosage: each capsule (not each serving) had to offer at least 1000 IUs of vitamin D.
As things currently stand, professional medical association recommendations are 600 IUs per day for adults, and 800 IUs per day for the elderly (1).
Many scientists have called for these recommendations to be increased, as evidence accumulates that higher levels may be necessary for optimal health.
Indeed, many clinical trials on the efficacy of vitamin D use higher than this 800 IU per day threshold. If any vitamin D supplement is considered “best,” it had better contain more than the minimum recommended amount.
Beyond the reported dose on the label, we also referred to independently verified metrics of the actual dosage delivered by the capsules. We dropped any supplements whose reported dose differed wildly from its actual dose, especially if it was delivering less vitamin D than advertised.
We also required that vitamin D supplements deliver their vitamin D in some type of lipid (fat) solution. Vitamin D is fat-soluble, so unlike water-soluble vitamins like vitamin C, its absorption could theoretically be adversely affected if it isn’t already dissolved in some kind of fat.
Finally, among the remaining supplements, we favored those without added sugar, binders, and fillers, as well as those which may include some additional benefits, such as the omega 3 fatty acids found in Nordic Naturals Vitamin D, and the leucine found in Thorne Research Vitamin D.
Benefits
Vitamin D helps your body absorb calcium. For that reason alone, it’s crucial that we get enough of this important vitamin in our diets. After all, calcium (along with phosphate) is the essential building block of bones.
If you don’t get enough calcium in your diet, or if you aren’t absorbing the calcium you do consume, bone production and bone tissue are severely impacted.
A huge number of people are deficient in vitamin D. It’s estimated that worldwide, around a billion people don’t get enough vitamin D (2).
There are very few food sources of vitamin D, but beef liver, cheese, mushrooms, and egg yolks provide tiny amounts. Fatty fish provide even more, but the best way to get your vitamin D is to drink fortified milk, get 15 minutes of sunshine every day, or take supplements.
In fact, it’s very difficult to get all the vitamin D from food sources.
Likewise, if you live in a northern part of the world it can be hard to get your vitamin D from sunshine, too. Not only that, but certain segments of the population have trouble getting enough of the vitamin from the sun, too: people with dark skin.
Finally, the elderly need more vitamin D than the rest of us. For all these reasons, vitamin D supplements are among the most widely necessary supplements on the planet.
Some evidence suggests that higher levels of vitamin D are protective against cancer. Thirty years ago, it was discovered that people living in northern areas had higher rates of colon cancer (3).
That led to the theory that lower vitamin D levels might increase colon cancer risk. Dozens of studies have been performed since then that strongly support the theory, but that doesn’t necessarily mean vitamin D supplements will lower the risk.
High levels of vitamin D may also prevent heart attacks. A 20-year study (4) found that men with vitamin D deficiencies had double the risk of having a heart attack.
There’s a strong link between D and heart health, but more research is needed.
Side effects
Vitamin D has been established as safe at doses of at least 4000 IU per day, but there is a risk of adverse effects if you take extremely high doses for a long time.
What’s ‘excessive’? Even doses of 10,000 IU per day is not known to cause significant side effects in the general population (5). These side effects at very high doses can be serious, and include dysregulated blood levels of calcium.
People with thyroid conditions seem to be at a higher risk for vitamin D toxicity, because of the relationship between vitamin D and thyroid hormones.
For people who do not have thyroid problems, though, typical doses of vitamin D found in over the counter supplements pose little or no risk.
Recommended dosage
Current recommendations from medical governing bodies recommend that adults take 600 IUs of vitamin D per day and the elderly take 800 IUs of vitamin D per day (6).
However, the current recommendations have generated substantial controversy. One scathing review of the most recent recommendations pointed out that with 600 IUs of vitamin D per day as your only input of vitamin D, your blood levels of the metabolically active form of vitamin D would only be one-third of the minimum biologically healthy level (7).
Second, the recommendations for vitamin D intake as it stands are based solely on evidence for its role in bone health, not its role in preventing chronic diseases or improving physical performance.
What’s a typical dosage among adherents to the ‘more vitamin D is necessary’ hypothesis? Usually a few thousand IUs per day, though researchers note that people who are overweight and obese need higher doses (as with most supplements) to get the same effect as a lean person, simply because of their greater body mass.
In terms of dosage safety, up to 4000 IUs of vitamin D is known to be safe, based on experimental research. Higher doses are not known to be dangerous, but have not had their safety firmly established in controlled research settings.
FAQ
Q: How is a vitamin D deficiency treated?
A: The treatment plan for a vitamin D deficiency depends on how low your blood levels of vitamin D are. For severely low blood levels, direct medical supervision is usually necessary.
This is diagnosed with a blood test for the 25-hydroxy form of vitamin D, which is the biologically active form. If your levels of 25-hydroxy vitamin D are extremely low, you might be given a massive initial dose to boost your levels of vitamin D rapidly, then sustain these levels with regular high-dose supplementation going forward.
Moderate to mild vitamin D deficiency is usually treated with a daily vitamin D supplement, typically that provides a few thousand IUs per day of vitamin D. If you are deficient in vitamin D, just taking the recommended 600-800 IUs per day for healthy adults is often not enough to actually raise your vitamin D levels.
Q: Can low vitamin D lead to weight gain?
A: There is strong evidence that vitamin D is related to being overweight or obese, but whether vitamin D deficiency will cause you to gain weight is less clear.
One study published in 2013 makes the opposite case: being overweight or obese disrupts hormone metabolism, which manifests as vitamin D deficiency (8).
This paper, which used genetic markers for vitamin D metabolism to study the causal effects of vitamin D on obesity, and vice versa, argues that obesity causes vitamin D deficiency, not the other way around.
From the perspective of preventing the negative health effects of vitamin D deficiency, the distinction is less important, as in either case people who are already overweight or obese may require vitamin D supplementation.
Q: What causes vitamin D deficiency?
A: The most proximal cause of vitamin D deficiency is a lack of exposure to enough sunlight for your body to synthesize vitamin D, or a lack of vitamin D in your diet.
Dietary vitamin D is very rare; it’s only found in significant amounts in fortified foods, and some mushrooms (which, incidentally, synthesize it the same way we do—by exposure to sunlight). So, if you are not getting outside and exposing your skin to direct sunlight, that’s the most likely cause of vitamin D deficiency.
Being overweight or obese seems to amplify the problem of vitamin D deficiency through disruptions in the body’s hormonal system, so even given the same amount of sun exposure, an overweight or obese person is more likely to develop vitamin D deficiency.
Q: Does vitamin D supplementation work?
A: Yes, as long as the dosage is high enough, vitamin D supplementation is a very successful strategy for raising levels of the biologically active form of vitamin D, which is the 25-hydroxy form (technically, 25-hydroxycholecalciferol).
Doctors have noted that it is difficult to effectively raise vitamin D levels with the moderate doses (600-800 IUs per day) recommended for healthy adults, so in cases of clinical vitamin D deficiency, doctors often use substantially higher doses, especially initially, to kick-start an increase in vitamin D levels in the blood.
Q: What does vitamin D do?
A: While named a “vitamin,” vitamin D is technically a hormone. It plays a critical role in skeletal health, and deficiencies in vitamin D (which go hand in hand with calcium deficiencies) are associated with a marked increase in risk for osteoporosis.
It also play a key role in metabolising other nutrients like magnesium too. Discoveries of its biological roles are still continuing to this day; it seems to play a link in both cognitive function and athletic performance as well.
Q: Is low vitamin D linked to depression?
A: Yes, one of the most under-reported threads on the science of vitamin D is its link to mental health. According to research that examined data from over 30,000 people, people with low levels of vitamin D have a more than two-fold increased risk of depression, compared to people who have high levels of vitamin D (9).
Among people with fibromyalgia, deficiency in vitamin D is also linked to anxiety as well as depression (10). While there are not as many randomized clinical trials of vitamin D for depression as there are for bone health and fracture prevention, the role of vitamin D in mental health should not be overlooked.
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Recap
Vitamin D plays a critical role in the development and maintenance of good bone health, and evidence is accumulating that demonstrates a role in promoting heart health, longevity, and athletic performance, to name just a few other benefits.
It’s naturally synthesized by your body via exposure to sunlight, but in the modern world, many people are vitamin D deficient.
Groups at particularly high risk for vitamin D deficiency include people with darker skin, people who live in northern climates, and the elderly.
Current recommendations for minimum intake are 600-800 IUs per day, but many experts advocate doses of at least 1000-2000 IUs per day. Dosing of up to 4000 IUs per day is known to be safe.
Given the good safety profile of vitamin D and the wide range of detrimental effects associated with deficiency, you should seriously consider a vitamin D supplement if you don’t expose your skin to the sun on a regular basis throughout the year.