✓ Reviewed and Fact-Checked by Dr. Jesse Ropat, PharmD, RPh, B.Sc.
Some things are just better together. While Vitamins D and K each provide their own benefits when taken separately, taking them together not only boosts these effects but creates new ones. As the saying goes, the sum is greater than its parts.
First, let’s talk about each vitamin separately.
First, vitamin D, aka “the sunshine vitamin.” Vitamin D we get primarily from plants, mushrooms, and yeast. Vitamin D3 is the form that we synthesize in our skin when we’re exposed to sunlight.
While vitamin D2 is more well-known, D3 is more effective for oral supplementation, which is why it’s often used in scientific studies and supplements. It plays a key role in calcium absorption and bone health.
Vitamin K2 is a form of vitamin K produced by bacteria in your gut or found in animal products like fish and beef. Vitamin K2 plays a significant role in the body’s blood clotting process and distribution of calcium.
In other words, D3 helps the body absorb calcium, while K2 helps direct calcium to where it’s needed.
When combined, vitamin D3 and K2 complement and increase each other’s effectiveness.
With all of this said, not all supplements are created equal. Today we wanted to share the best products on the market. Every product on our list is third-party tested and cGMP-approved.
*Note: We do have affiliate links throughout this article, which means we receive a commission if you purchase from any of our links. This supports our mission to bring complicated health and fitness info in an entertaining package. And it keeps us from putting up annoying things like banner ads. Those suck.
Best D3 + K2 Overall: Performance Lab
Best D3 + K2 for Vitamin D Deficiency: Slim Sciences
Best Organic D3+ K2: Pure Synergy
Best D3 + K2 Liquid Drops: Double Wood
Best Liposomal Vitamin D3 + K2: Performance Lab
Best Vegan D3 + K2: Performance Lab
Best D3 + K2 for children: Nordic Naturals Gummies
The Lifeforce D+K formula is the only one of its kind to feature ampli-D®, a patented form of vitamin D clinically proven to raise vitamin D levels three times faster than ordinary vitamin D supplements.
This focus on bioavailability and absorption, and with the research to back it up, is why this product is #1 on our list.
I also like that the dose is 2400 IU of Vitamin D, which is right around the optimal dose for many. They also use a patented form of Vitamin K2. Each tablet contains 300mg of Vitamin K. This is another area where this product stands out.
Their form, K2Vital® activates Gla protein, which is one of the strongest inhibitors of blood vessel calcification and arterial stiffness. This in turn can support heart health, which is a claim most other products simply can’t make.
For all these reasons, Lifeforce D+K is our #1 choice.
For overall quality to support your health Performance Lab D3 +K2 is another top choice.
A few elements make this product stand out. First, there’s the focus on increased absorption. They use liposomal vitamin D3 from algae, which means it’s protected in a coat of phospholipids to help it get absorbed.
Higher absorption means you can take a lower dose and get the same benefit, or even more benefits. Unlike Lifeforce, they don’t have the research to demonstrate the increases in absorption, but it’s a great theory, and the research on liposomes in general is strong.
Second, the use NutriGenesis® K2 for improved absorption as well. This patented form is designed to be ‘nature-identical’ so you get vitamin K2 in a form close to what you find in whole foods. They even use patented NutriCaps®, so you know you’re getting quality right down to the capsules.
This product is suitable for vegans and contains NO soy, egg, fish, shellfish, dairy, peanut, tree nuts, wheat, or other allergens. It’s non-GMO and non-irradiated. it’s gluten-free, free of synthetic additives, artificial colors, and preservatives. Simply, Performance Lab D3+K3 is one of the best products out there.
Oh, one other great benefit is they’re the best on our list for international purchases. Whether you’re in Canada, the European Union, the UK, Australia, or almost anywhere on the global, you can get it without paying ridiculous shipping fees.
Hot on its heels in turns of quality and effectiveness is Slim Sciences Vitamin D3 & K2.
Every capsule contains 125 mcg (5000 IU) of vitamin D3, and 200 mcg of vitamin K2. It’s gluten-free, vegan, non-GMO, and free of allergens, so it’s also a clean product.
One element that stands out about Slim Sciences’ product is that it’s manufactured in an FDA-approved facility in the USA.
Finally, they have a 180-day money-back guarantee.
They even have a buy 1, get 2 offer going on right now, so the price point makes it a great value.
For all of these reasons, Slim Sciences D3 & K2 comes in at #2.
This is another unique product that stands out for a few key reasons. First they’re the only ones that use certified organic ingredients. Like Performance Lab, they go an extra step to sustainably source the vitamins and go with vegan sources.
Next, it includes an organic whole-food blend, including prebiotics, to help make it easy on the stomach. If you’ve had stomach distress from supplements before, this is a great option to try.
In terms of value and simplicity, look no further than Transparent Labs.
For just $20 bucks, you get 120 softgel capsules with a 5000 IU dose of vitamin D3 and 100 mcg of vitamin K2. The only other ingredient is the softgel capsule.
Transparent Labs is known for their, well, transparency. They have a certificate of analysis available for all of their supplements.
With just one capsule a day, you will be covering your bases. In fact, 5000 IU is enough even if you have a known vitamin D deficiency.
That’s actually the downside of this product. 5000 IU of vitamin might be overkill for many people.
Double Wood’s D3 and K2 supplement offers high-quality ingredients for a good price. It’s also potent, with 5000 IU of vitamin D3 per serving. It also includes MCT Oil as a base, which might help with absorption. It is also U.S.-manufactured, vegan-friendly, gluten-free, soy-free, and non-GMO.
You may also notice this product has 200 mcg of vitamin k2, so you get a higher dose of k2 than most products.
With the liquid vitamin option, you can also vary your dose depending on your needs. You can take an ultra-high dose, or a lower dose.
Each bottle contains 30 servings. Double Wood offers a money-back guarantee.
This D3K2 product uses a liposomal delivery method to further increase bioavailability. Liposomes are lipids that are designed to protect ingredients as they go through the digestive tract, so more of it goes into your bloodstream.
Quicksilver’s Vitamin D3 + K2 liquid has 2500 IU of vitamin D per serving and 90 mcg of vitamin K2.
It’s also a super pure and high-quality product. It’s tested free of allergens, tested gluten-free, non-GMO, and vegetarian-friendly. While a bit more expensive than the previous products on our list, with 100 servings and top-tier quality, you can’t go wrong.
Nordic Naturals has a pomegranate-flavored chewable gummy version. This is great for kids for a few reasons. First of all, kids generally prefer gummies. Look, I’m not a parenting expert, but I remember being a kid and the Flintstone vitamins were always the move.
Second, it has a smaller dose, 1000 IU, that’s perfect for people who need less.
With just 2 grams of sugar per gummy, even adults can get in on the fun with this product.
Thorne Research’s D and K2 supplement is small but mighty. Just one bottle contains 200 servings. Its solution is free of gluten, dairy, and soy. It can be taken on its own or added to any beverage or meal. In addition, Thorne Research offers a testing kit on its website to determine if a vitamin D supplement is necessary for you.
Sports Research offers a D3 and K2 supplement made with intentional, plant-based ingredients. It contains D3 derived from Lichen, K2 derived from chickpea, and virgin coconut oil all in a plant-based capsule. It’s manufactured in the USA and contains up to 60 servings.
MRM Nutrition’s Vegan Vitamin D3 and K2 is another supplement on our list made with plant-based ingredients. Its D3 is extracted from Lichen and is free of nuts, soy, gluten, and yeast. Each bottle contains 60 servings if taking 1 capsule per day (which is recommended, because it contains over 300% of your daily value).
NOW Foods Vitamin D-3 and K-2 offers a quality supplement at a great price point. Each capsule contains 1000 IU of vitamin D3 and 45 mcg of K2. This is on the lower side. Each bottle provides up to 120 servings. It comes in a vegetarian capsule.
Research shows that combining D3 and K2 might do the following:
A review of over 80 studies concluded that vitamins D3 and K2 were more successful at supporting bone health when used together than when used alone. This may be because D3 helps the body absorb calcium while K2 helps direct calcium to where it’s needed. This makes it a key combo for bone density and strong bones.
So if you want healthy bones, this may be a key supplement in your arsenal.
Vitamin D3 and K2 can work together to fight against cardiovascular disease and reduce inflammation. An imbalance between vitamin D and vitamin K can result in more calcium being deposited into our blood vessels and hardening them, rather than in our bones. This is called “calcification” of the blood vessels. It’s a dangerous combination, resulting in weaker bones, increased risk of osteoporosis, and heart disease.
While vitamin C is all the rage for fighting colds, there actually isn’t good evidence that vitamin C supplementation supports the immune system and shortens colds. In contrast, recent compilations of research, like this 2017 meta-analysis, suggest that vitamin D supplementation can prevent acute respiratory infections (aka, a cold).
For immune function support, this is one of the few tried-and-true supplements out there.
An estimated 40% of Americans aren’t getting enough vitamin D each day. A deficiency of vitamin D can lead to muscle weakness, bone loss, osteoporosis, and bone fractures. Taking a Vitamin D3 supplement will, well, increase your vitamin D levels.
You can have too much of a good thing, and vitamin D is no exception. Excess vitamin D, known as vitamin D toxicity, can cause high calcium levels that result in the following side effects:
Although vitamin D toxicity is rare, it’s best to follow the recommended supplement guidelines to avoid these symptoms.
As always, the best way to determine if a D3 and K2 supplement is right for you is by consulting a healthcare professional. If you want stronger bones and improved cardiovascular health, a D3 and K2 supplement may be worth the try.
Vitamin D is a fat-soluble vitamin. That means, it gets absorbed better in conjunction with other fats, rather than with water. Encasing it in a softgel, fat-based capsule, may support absorption. This is why vitamin D and omega-3 supplementation are popular as a combination; it may make the vitamin D more bioavailable. You may also see people recommend you take your vitamin D supplement with olive oil or another healthy fat.
While a multivitamin may have its place, for most people you pay for a ton of ingredients you don’t need (and just pee out), while not getting enough of what you do need. A better strategy is to figure out what you need. Vitamin D and K are common deficiencies, which is why it often makes more sense to pick up a supplement like this.
For a whole-food-based nutrition solution to cover your bases, we recommend looking into a greens powder supplement.
For supplements, vitamin D3, (AKA cholecalciferol) is the most studied form. It’s the form we absorb best as a dietary supplement. Per the research, it’s more effective at raising our vitamin D levels. The ideal dose of daily vitamin D intake varies by age. In general, adults are safe to intake 4000 IU of vitamin D per day, or up to 25000 IU of vitamin D per week. Individuals who are known to be deficient may take even more, and should discuss their specific daily intake with their healthcare provider. It is possible to take too much vitamin D, so stick with a regiment that you’ve discussed with your healthcare provider.
Vitamin D2 (ergocalciferol) and D3 (cholecalciferol) are two different forms of vitamin D. Vitamin D2 comes from plant-based sources like yeast and mushrooms, while D3 is produced in the skin in response to sun exposure and is also found in animal-based foods like egg yolks and beef liver. As mentioned, D3 seems to be more effective at raising our vitamin D levels.
Vitamin K1 is what you’ll find in leafy green vegetables, while K2 is in fermented foods and animal products. Research has suggested that K2 (menaquinone-7) is more effective for bone health, and generally has higher absorption. That’s why it’s the most popular form in supplements.
Sure, you can. Mowever, most of us don’t. The reality is that modern lifestyles mean we’re inside a lot more, and practically speaking can’t get the vitamin D we need.
This is especially true during the winter months when we get less sun exposure.
Also, vitamin K does NOT come from the sun and is also a common deficiency.
In an ideal world, we all get enough sunlight, and eat enough vegetables and fermented dairy to maintain our bone and cardiovascular health.
You should take vitamin D3 and K2 with a meal that contains healthy fats. These vitamins dissolve in fat, so eating them with fat helps your body absorb them.
If you’re not taking with a meal, one common strategy is stack this with an omega-3 fatty acid supplement. That gives you some fats to help the absorption.
Some studies suggest that vitamin D3 might improve sleep quality, but researchers need to explore this further. The effect of K2 on sleep isn’t clear.
You should usually take vitamin D3 and K2 with a meal, often at breakfast or lunch. Taking them later in the day might disturb sleep for some people, as vitamin D can have an alerting effect in some cases.
The best way to find the right dose is by getting your vitamin D levels tested and following your doctor’s instructions. Typical doses range from 1000 IU to 5000 IU.
There are lots of great brands out there. Performance Lab is our top choice for various reasons, but other great products might suit your goals, needs, and values.
Taking vitamin K2 and D3 together can enhance the effectiveness of both. Vitamin D3 helps your body absorb calcium, while K2 directs the calcium to your bones and teeth instead of soft tissues. This combination supports bone health.
If you’re on blood-thinning medications or have certain health conditions, you might need to avoid K2 supplements. Always consult with your healthcare provider to see if K2 is right for you.
Fatigue, muscle weakness, bone pain, and mood changes can signal vitamin D deficiency. To know for sure, see your healthcare provider and get tested.
This is the shorthand for menaquinone-7, which is the chemical term for vitamin K2. On some labels, you’ll see “vitamin K2 mk-7” to make it sound fancy and special, but they’re all synonyms.
Vitamin D3 and K2 work synergistically to support bone health. Vitamin D3 helps the body absorb calcium, a crucial mineral for bone strength and density. Vitamin K2, on the other hand, helps direct the absorbed calcium to the bones and teeth, rather than allowing it to deposit in soft tissues. By working together, D3 and K2 ensure that calcium is utilized effectively in the body, promoting strong and healthy bones.
This depends on individual factors such as age, skin tone, sun exposure, dietary intake, overall health, and most importantly, your actual vitamin D levels. Some people may have sufficient vitamin D levels through diet and sunlight, while others, especially those at higher risk of deficiency, may benefit from daily supplementation.
To decide whether you take it daily, work with your healthcare provider.
Disclaimer: Talk to your healthcare provider before taking any dietary supplement, including Vitamin D3 and K2.