The Best Vitamin D3 Supplements in 2026

Roughly 40 percent of American adults have vitamin D blood levels below 20 ng/mL, the cutoff most labs flag as deficient. That figure comes from NHANES survey data, not from a supplement company. And it makes sense. We work indoors, we wear sunscreen when we don't, and north of Atlanta the winter sun sits too low for your skin to make meaningful vitamin D from about October through March. This is one of the few supplements where the case for taking it is boring and solid rather than hyped. The interesting shift in recent years is that the default recommendation moved from plain D3 to D3 paired with vitamin K2, on the theory that K2 helps steer the extra calcium you absorb into bone instead of soft tissue.

If you just want the answer: buy Nutricost Vitamin D3 + K2. One small softgel gives you 5,000 IU of D3 with 90 mcg of K2 in the well-studied MK-7 form, it's third-party tested, it costs a few cents a day, and more than 5,000 reviewers agree it does the unglamorous job fine. Everything else in this guide exists for a specific situation, like a tested deficiency or a hatred of pills.

Disclosure: we may earn a commission if you buy through some of the links on this page, at no extra cost to you. This article is general information, not medical advice, so talk to your doctor before starting any supplement, especially at higher doses.

Product	IU per serving	With K2	Form	Best for
Nutricost Vitamin D3 + K2	5,000	Yes, 90 mcg MK-7	Softgel	Most people
Luma Nutrition D3 + K2	10,000	Yes, MK-7	Softgel	Tested deficiency, doctor supervised
NOW Foods Vitamin D3	2,000	No	Softgel	Cheap maintenance dosing
Nordic Naturals Vitamin D3 Gummies	1,000	No	Gummy	People who hate pills
Thorne Vitamin D/K2	1,000 per 2 drops	Yes, 200 mcg MK-4	Drops	Flexible dosing
Sports Research D3 + K2	5,000	Yes, 100 mcg MK-7	Softgel	Plant-based softgel fans

Nutricost Vitamin D3 + K2: best for most people

Here's the honest frame for this whole category. Vitamin D3 is a commodity. Nearly every brand buys cholecalciferol made from lanolin, the wax from sheep's wool, and drops it into an oil-filled softgel. What actually separates products is dose, whether K2 comes along, and whether anyone tests the finished pills. Nutricost gets all three right and charges less than almost anyone. You get 5,000 IU of D3 plus 90 mcg of K2 as MK-7 in each softgel, verified by ISO-accredited third-party testing, usually for under 15 dollars a bottle. The softgels are small, and the 5,000-plus review count means the track record is long, not lucky.

Cons: 5,000 IU daily is above the official 4,000 IU upper limit, which is fine for winter or every-other-day dosing but worth knowing before you set a daily reminder. There's no sport-certification stamp for tested athletes. And the label looks like a spreadsheet. None of that changes the math. Check the current price on Nutricost D3 + K2 here.

Luma Nutrition D3 + K2 10,000 IU: for tested deficiency, with a doctor involved

This is not a starter product. 10,000 IU is two and a half times the upper limit, and nobody should take that long term on a hunch. But if bloodwork puts you well under 20 ng/mL and your doctor wants your levels up quickly, one high-dose softgel with K2 included beats swallowing handfuls of smaller pills. Luma Nutrition's D3 + K2 pairs the 10,000 IU with MK-7 and keeps the capsule easy to take.

Cons: Luma is a smaller brand with a shorter history than NOW or Thorne. The dose makes it easy to buy for the wrong reason, since bigger numbers look like better value. And once your level is back in range, you should step down to something like the Nutricost 5,000. Treat this bottle as a repletion tool with an end date, not a subscription.

NOW Foods Vitamin D3: the budget classic without K2

NOW is the rare supplement company that runs serious in-house testing labs and has been boringly consistent since 1968. Its plain D3 comes in 1,000, 2,000, 5,000 and 10,000 IU strengths, and the 2,000 IU bottle often works out to about two cents a day. If you already get K2 from a separate supplement, a good multivitamin, or a natto habit, plain D3 is all you need, and this is the cheapest reliable way to get it.

Cons: no K2, obviously. The wall of nearly identical bottles makes it easy to grab the wrong strength, and the brand does nothing to help you choose. Fine product, zero hand-holding.

Nordic Naturals Vitamin D3 Gummies: for people who hate pills

Gummies are usually where supplement quality goes to die. The candy format is hard to dose precisely, and plenty of tested gummies contain more or less than the label claims. Nordic Naturals is the exception worth naming, because the company publishes a certificate of analysis for every batch and its label accuracy record is genuinely good. Each gummy carries 1,000 IU of D3, which is a sensible maintenance dose, and compliance is the whole game with vitamin D. The pill you actually take beats the better pill you skip.

Cons: the highest cost per IU on this list by a wide margin, no K2, and a gram of sugar per gummy. If you need 5,000 IU, five gummies a day gets expensive and silly fast.

Thorne Vitamin D/K2: drops for flexible dosing

Two drops give you 1,000 IU of D3 with 200 mcg of K2, so one bottle can run 1,000 IU in July and 4,000 IU in January. Thorne is the brand practitioners and pro teams reach for, its manufacturing standards are as tight as this industry gets, and a single dropper bottle lasts months. For households sharing one product across different doses, drops make real sense.

Cons: it costs several times what Nutricost does per 1,000 IU. Thorne uses K2 as MK-4 rather than MK-7, and MK-4 clears your blood in hours while MK-7 sticks around for days, so the form here is arguably weaker at this dose. Also, counting drops gets old by about week three.

Sports Research D3 + K2: the same idea in nicer packaging

5,000 IU of D3 with 100 mcg of MK-7 in a coconut oil base, wrapped in a plant-based softgel. It's a good product, third-party tested, non-GMO verified, pleasant to swallow. It's also, functionally, the Nutricost formula at roughly twice the price. If the coconut oil carrier or the vegetarian-friendly shell matters to you, or you catch it on sale, buy it without guilt.

Cons: price, and that's mostly it. This product is the clearest demonstration of the commodity point. In this category you're often paying for branding, not chemistry.

Do you need K2 with your D3

The mechanism is real. Vitamin D increases how much calcium you absorb, and vitamin K2 activates matrix Gla protein and osteocalcin, the proteins that pull that calcium into bone and keep it out of artery walls. Pairing them looks smart on paper. The clinical evidence is thinner than the marketing suggests, though. The best long-term data is a three-year Dutch trial in which 180 mcg of MK-7 daily slowed bone density loss in postmenopausal women. Trials on artery calcification are smaller and mixed. What tips the scale is cost: adding K2 to a D3 softgel costs the manufacturer pennies, adds a dollar or two to the bottle, and has a clean safety record. Think of it as cheap, reasonable insurance rather than a proven necessity. One hard exception: if you take warfarin, K2 interferes with the drug. Stick to plain D3 and tell your doctor.

How much vitamin D should you take

The official RDA is 600 to 800 IU depending on age, and the NIH Office of Dietary Supplements sets the tolerable upper intake at 4,000 IU per day for adults. In practice, most supplements sell 1,000 to 5,000 IU, and the Endocrine Society's 2011 guidance suggested adults may need 1,500 to 2,000 IU daily just to hold blood levels above 30 ng/mL. Its 2024 update turned more conservative for healthy adults, which tells you how unsettled the science still is. If you're unsure where you stand, spend the 40 dollars on a 25-hydroxyvitamin D blood test instead of guessing. Two practical notes. Vitamin D is fat soluble, so take it with a meal that contains some fat, which measurably improves absorption. And toxicity is real, not a scare story. Sustained intakes above roughly 10,000 IU a day can push calcium into the blood and cause nausea, kidney stones, and worse. Nobody gets there from sunshine. People get there by stacking a mega-dose capsule on top of a fortified diet and a multivitamin for months. Above 4,000 IU daily, get a doctor involved and retest.

FAQ

Should I take vitamin D in the morning or at night?

Whenever you'll actually remember it, ideally with your biggest meal. The fat in the meal matters more than the clock. Some people swear evening vitamin D disrupts their sleep, but the evidence for that is anecdote grade. Consistency beats timing.

Is D3 better than D2?

Yes. Both raise blood levels, but D3 raises 25-hydroxyvitamin D higher and holds it there longer than D2 does. Every product in this guide is D3. The main historical reason to use D2 was vegan sourcing, and lichen-derived vegan D3 has mostly solved that.

How long until my levels come up?

Weeks, not days. At a steady dose, blood levels typically plateau after six to eight weeks. If you're correcting a deficiency, retest at about three months, then drop to a maintenance dose rather than riding the high dose indefinitely.

Can I just get vitamin D from food?

Rarely. A serving of salmon has 400 to 600 IU, a cup of fortified milk about 120 IU, and after that the menu thins out fast. Getting even 1,000 IU a day from food takes deliberate effort. Summer sun works. A northern winter mostly doesn't.