The Best Vitamin D Supplement
To find our top picks, we consulted with doctors and nutritionists from across the country, read through hundreds of ingredients labels, and utilized the results from three different independent lab tests. In the end, we found eight supplements that stand the best chance of boosting your vitamin D levels.
A lab-certified vitamin D3 supplement at the lowest price we found — $0.01 per supplement.
Nature Made D3 1000 IU
This lower dose received just as much third-party praise and is sold at nearly every drugstore. It's a few cents more at $0.04 per supplement.
About one-third of Americans don’t get enough vitamin D. And as researchers continue to uncover the many roles vitamin D plays in our health, it has become increasingly obvious that it’s important we get enough — and a quality vitamin D supplement is the easiest way to do that.
Our top pick is Kirkland Signature Extra Strength Vitamin D3 2000 IU. One pill contains 2,000 IU of vitamin D3, and its purity and label accuracy are certified by both the United States Pharmacopeial Convention and Labdoor, two reputable third-party supplement watchdog groups. It’s only $0.01 per serving, too.
Nature Made received just as much praise from third party test labs, but one bottle contains 220 pills (less than half as much as Kirkland Signature), for twice the price. And because each Nature Made supplement contains 1000 IU of vitamin D, you might end up need to take more than one supplement per day depending on your doctor’s recommendation.
While we don’t recommend paying more for a nearly identical product, Nature Made scores points for its availability. You can find it nearly anywhere with a pharmacy. If you prefer to buy your supplements in stores, or just want a lower dose, Nature Made Vitamin D3 is the way to go.
We also found six other options from Carlson Labs,Country Life, Nature’s Way, Nordic Naturals, NOW Foods, and Solgar. These supplements met all of our basic criteria, but were slightly more expensive or had fewer third-party certifications.
How We Found the Best Vitamin D Supplement
We started by looking for popular brands that are readily available through online retailers (like Amazon and Vitacost) or at chain grocery stores and pharmacies. We found a bunch: 239 vitamin D supplements in a variety of forms, including softgels, tablets, gummies, liquids, and sprays. Then we talked to doctors, nutrition experts, and a vitamin manufacturer before looking at each product’s ingredients label, product purity, and dosage accuracy to find the best vitamin D supplement on the market.
It needed to include vitamin D3.
In our search for the best vitamin D supplement, we learned that there are actually two types of vitamin D: D2 (ergocalciferol), which comes from plants, and D3 (cholecalciferol), which is manufactured using fish oil or — more commonly — lanolin taken from sheep wool and subjected to ultraviolet (UV) radiation. This may sound scary, but UV radiation is what our bodies use to make natural vitamin D when our skin is exposed to sunlight.
Most people should choose a supplement with vitamin D3, since it’s absorbed more easily than D2.
Dr. Joe Feuerstein, associate professor of clinical medicine at Columbia University and director of integrative medicine at Stamford Hospital in Stamford, Connecticut, told us, “D3 mimics the way our bodies make vitamin D from sunlight and it’s more easily absorbed, making it the best option for most people.”
Because vitamin D3 is more widely recommended and more available in stores, we cut any supplements that use D2.
No third-party testing? No way.
The Food and Drug Administration (FDA) regulates food products, but not dietary supplements. So it’s anybody’s guess if what’s in a pill actually matches what’s on its bottle label. Some supplements contain lead or other contaminants, and product ingredients can vary widely. In fact, Labdoor, a reputable third-party testing company, found that the actual dosage of vitamin D supplements sometimes exceeded what was listed on the label by as much as 900 percent. That’s why we required all of our top picks to be vetted by at least one of three reputable, independent labs:
United States Pharmacopeial Convention (USP) – A scientific nonprofit that sets standards for quality and purity in medicines and food supplements in the US and more than 140 other countries.
Labdoor – A free consumer resource that focuses on testing dietary supplements for purity, accuracy, and value.
National Sanitation Foundation (NSF) – An independent organization that sets worldwide standards for consumer product safety.
We also looked for minimal additives — including other supplements.
Ever wonder why vitamin D, like many supplements, contains glycerin, water, cellulose, or other fillers? We did too, so we asked Jamie Shuck, brand manager for Vitabiotics, one of the UK’s largest vitamin manufacturers. “Vitamin D is needed by the body only in tiny microgram amounts, which is barely a speck in its pure form — far smaller than a grain of rice and too small to even pick up,” Shuck explained. “Therefore, all vitamin D supplements must be formulated with other ingredients to increase the volume of the product, so customers are able to measure a safe and accurate dose.”
While it’s impossible to find a vitamin D supplement that contains just vitamin D, we did look for products that avoided questionable additives like sugar, flavoring, artificial color, and preservatives.
We also chose products containing vitamin D with no other dietary supplements. According to the experts we talked to, almost everyone needs a vitamin D supplement, while only some of us need or want additional ingredients like calcium or CoQ10.
Dr. Feuerstein also made a strong case for eliminating proprietary blends: “The challenge with proprietary blends is it’s hard to know the specific dose of vitamin D in each pill,” he said, “and that makes it difficult to treat someone who has a vitamin D deficiency.”
Each pill needed to include a fatty oil to help with absorption.
Like vitamins A, E, and K, vitamin D is fat-soluble, which means it dissolves in fat rather than water. That means D is best absorbed by the body when taken with fatty foods. That’s why many vitamin D supplements also contain an oil in addition to D3.
If you choose a supplement that doesn’t include oil, nutritionist Shereen Lehman recommends taking it with a little added fat. “You don’t need a lot,” she explains. “A salad with dressing, or a little cheese, avocado, or meat are good. Even seafood would have enough natural fat to help with vitamin D absorption.”
But we wanted to make it easy, so we cut any supplements that didn’t include some form of oil or fatty acid from olives, soybeans, or another healthy source.
We didn't take dosage into account.
From there, we had eight supplements to choose from. Each has positive third party ratings and only contains vitamin D3, some oil, plus gelatin and water or glycerin to form the rest of the supplement.
The only real difference between them is the amount of vitamin D3 per supplement. So how much vitamin D do you need?
The Recommended Daily Allowance for most adults is 600 IU. But the majority of the supplements we looked at contained between 1000 and 2000. Why so much? Our experts suggested that the RDA — which dropped from 2000 IU all the way down to 600 IU in 2010 — might not be enough to prevent a vitamin D deficiency.
But there’s no hard and fast rule — and much of it depends on environmental factors. An office worker in cloudy Seattle will likely need more vitamin D than a lifeguard in Los Angeles, for example. Before you start taking supplements, talk to your doctor about the right dosage for you.
Popular nutrition expert Dr. Andrew Weil recommends 2,000 IU of vitamin D3 per day for most people, and Dr. Feuerstein agrees: “If you follow the current RDA of vitamin D, which is 600 IU per day, I can pretty much guarantee that unless you’re a child, it won’t be anywhere near enough.” He recommends 2,000 IU per day for his adult patients, with higher doses for patients who have been diagnosed with a vitamin D deficiency.
2000 IU might be the right dose for most people, but that doesn’t guarantee that it’s right for you. Your age, where you live, and the medications you take all play a role in how much vitamin D you need. Before you start taking supplements, talk to your doctor about the right dosage for you.
Our Pick for the Best Vitamin D Supplement
Kirkland Signature Extra Strength Vitamin D3 stood out because it met all of our criteria, for the best value. To start, we liked the short list of ingredients: 2,000 IU of vitamin D3 (as cholecalciferol, which mimics the way the body naturally processes vitamin D), soybean oil (rich in heart-healthy polyunsaturated fats), plus gelatin, glycerin, and water for the softgel capsule.
Kirkland Signature even earned kudos from not one, but two independent labs. Its label bears the USP symbol, arguably the gold standard for product testing. USP certification is recognized around the world.
If product quality, minimal additives, and accurate labeling aren’t enough, Kirkland Signature Extra Strength Vitamin D3 is a good value, too. At about $0.01 per serving, it was less than half the cost of our other top contenders.
We loved the Costco-sized bottle, which contained 600 softgels that were as small as any we tested. After all, if you’re going to make vitamin D supplements a part of your daily routine, you might as well make it easy on yourself: one tiny pill that’s easy to swallow, in a bottle that will last for a good 20 months. At $3.50 per year, Kirkland Signature Extra Strength Vitamin D3 is an inexpensive way to stay up on your vitamin D intake.
The only drawback? If you prefer to purchase your vitamin supplements in stores, you may be out of luck. The Kirkland Signature brand is exclusive to Costco, which requires it’s shoppers to purchase a monthly membership fee.
We liked Nature Made D3 tablets for many of the same reasons as Kirkland Signature: It’s the only other D3 supplement tested by both USP and Labdoor to ensure purity and potency, plus it includes soybean oil to help boost absorption. But unlike Kirkland Signature, a Nature Made bottle of 250 pills costs about $15 (8 more cents per serving). In other words, you’ll pay more money for fewer supplements.
Nature Made also contains 1000 IU of vitamin D per pill (half as much as Kirkland Signature). Our experts recommend 2000 IU per day to most of their adult patients. If your doctor agrees, you’ll need to take two pills per day. But the tablets are tiny, and a lower dose means you can easily take more or less vitamin D as needed.
Both brands are available through Amazon, but if you prefer to buy your supplements in a brick-and-mortar store, you can find it at grocery stores and pharmacies nationwide including Target, Walgreens, and Safeway.
Did You Know?
Most people aren’t getting enough vitamin D.
An estimated 41% of US adults are vitamin D-deficient. And that has serious long-term effects. “Without vitamin D you won’t absorb calcium in your gut, which leads to an increase in bone loss,” says Dr. Feuerstein. “But vitamin D goes so far beyond that. We have vitamin D receptors in nearly all the tissues of the body, and we’re learning about its effect on cancer, heart disease, multiple sclerosis, and in autoimmune disease.” Shuck adds that “vitamin D also has other key functions in the body, such as helping to maintain normal immune system functioning.”
It’s difficult to get adequate vitamin D through diet alone.
There are food sources of vitamin D, notes nutritionist Shereen Lehman: “Oily fish like salmon and tuna have some vitamin D, and eggs do as well. Mushrooms like maitake and chanterelle can be a good source, as can portabella mushrooms grown in UV light. Otherwise, look for foods fortified with vitamin D like milk, breakfast cereals, and many brands of nut milk.”
But can you get enough D just from food sources? That depends on how hungry you are. The National Institutes of Health (NIH) found that even foods rich in vitamin D require multiple servings to meet the recommended 600 IU per day.
And more sun exposure comes with its own risks.
Some medical researchers, like Dr. Holick, recommend getting 15 minutes of unprotected sunlight per day — in the middle of the day when the sun is brightest. And Dr. Weil recommends 10 minutes of sun per day. But the American Academy of Dermatology disagrees, and suggests we use skin protection (clothing and sunscreen with an SPF of 30 or higher) every time we’re out in the sun, to prevent skin cancer.
So what’s the right answer? We suggest checking with your doctor to find out what’s right for you.
A simple test will tell if your vitamin D level is low.
Many doctors routinely check vitamin D levels during a patient’s annual physical exam. A simple blood test, called the 25(OH)D, will determine the amount of vitamin D stored in your body from all sources, including sun, diet, and supplements. In fact, the test measures stored vitamin D as far back as 15 days, which makes it the ideal way to get an accurate measurement of your vitamin D level.
If your doctor doesn’t already check your vitamin D levels during your annual exam, don’t be afraid to ask for the test.
Another option: a home testing kit for under $70 from the Vitamin D Council. You prick your finger and place a drop of blood on blotting paper, and then send it to the lab, which will mail you your results.
If your test determines that you’re deficient in vitamin D, Dr. Feuerstein suggests working with your medical provider to determine the best dosage — and getting tested every six months until you reach your goal. He routinely tests his patients twice a year to determine if their vitamin D level changes from summer to winter.