Quick answer
Vitamin D and vitamin K2 are often paired because vitamin D helps the body absorb calcium and vitamin K2 activates proteins that help direct calcium to bone. Thorne’s Vitamin D + K2 liquid, for example, suggests 2 drops (1,000 IU D3 and 200 mcg K2) one to three times daily. Both are fat-soluble, so take them with a meal that has some fat. Anyone on warfarin should not start K2 without their prescriber.
Key takeaways
Vitamin D and vitamin K2 are often paired because vitamin D helps absorb calcium and K2 helps direct it toward bone.
K2 comes in different forms, and MK-7 stays in the blood much longer than other forms of vitamin K.
Both are fat-soluble and best taken with a meal, and anyone on warfarin should not start K2 without their prescriber.
If you have questions about whether vitamin D and K2 fits your plan, a short call is a simple place to start.
Vitamin D and K2 combinations are some of the most popular supplements. This page explains why they are paired, how labels dose them, and the key cautions. It is educational information. For more on each, see Who should consider vitamin D3 and Who should consider vitamin K2 (MK-7), and our Vitamin D blood test (25-OH) guide.
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Why they are paired
A narrative review describes how vitamin D and vitamin K work together in calcium handling, with vitamin K needed to activate proteins such as osteocalcin and matrix Gla protein (van Ballegooijen 2017). The authors note that more trials of the combination are needed.
Label dosing
Thorne Vitamin D + K2 liquid lists 1,000 IU of vitamin D3 and 200 mcg of vitamin K2 per 2 drops, with a suggested use of 2 drops one to three times daily, or as recommended by your practitioner. Capsule combinations often provide 1,000 to 5,000 IU of D3 with 90 to 180 mcg of K2. The right vitamin D amount depends on your blood level, so testing helps.
MK-4 vs MK-7
K2 comes in different forms. MK-7 stays in the blood much longer than vitamin K1 (Schurgers 2007), so it is usually taken once daily in microgram amounts. MK-4 is cleared faster and is often dosed more than once a day. Thorne’s liquid uses MK-4.
Timing
Both vitamins are fat-soluble, so most people take them with their largest meal of the day.
Cautions and who should check with a provider
If you take warfarin or another vitamin K antagonist, do not start K2 without your prescriber, because even low-dose MK-7 changed vitamin K status in healthy adults (Theuwissen 2012). High-dose vitamin D can raise calcium too much, and testing your 25-OH vitamin D level helps guide the amount.
Ask first if you have kidney disease, high calcium, sarcoidosis, or parathyroid issues, or if you are pregnant or nursing.
Questions to bring to your clinician
These questions can help you get the most out of your next visit.
Should I check my vitamin D level before deciding on vitamin D and K2?
Is vitamin D with K2 a reasonable choice alongside my current medications and supplements?
Would it be worth checking any labs before I try vitamin D with K2, or is my history enough to decide?
What would tell us that vitamin D with K2 is working well for me, and how long should we wait before reviewing it?
Practitioner-grade options in my Fullscript catalog: if you and your clinician decide a supplement makes sense, my supplement guide by health goal links to the practitioner-grade products I trust.
Frequently asked questions
Should vitamin D and K2 be taken together?
They are often paired because they work together in calcium handling. Ask your provider whether you need both.
How much K2 should I take with vitamin D?
Labels commonly pair 1,000 to 5,000 IU of D3 with 90 to 200 mcg of K2. Your provider can tell you what fits you.
When is the best time to take vitamin D and K2?
With a meal that contains some fat, often your largest meal.
Can I take K2 if I am on a blood thinner?
Not without your prescriber. K2 can affect warfarin.
Can I take vitamin D with magnesium?
Yes. They are often taken together, and magnesium plays a role in how the body uses vitamin D.
Can I take vitamin D and K2 with calcium?
Many people take them together. Ask your clinician whether you need extra calcium, since many people get enough from food.
Can I take vitamin D with a multivitamin?
Yes, but check the multivitamin label first so you know your total daily vitamin D.
Can I take vitamin D and K2 at night?
Yes. Taking them with a meal that contains fat matters more than the time of day.
Related reading
- Who should consider vitamin D3
- Who should consider vitamin K2 (MK-7)
- Vitamin D blood test (25-OH) guide
- Magnesium glycinate vs citrate vs oxide vs L-threonate
- Creatine for women over 40, 50, and 60
Sources
- Thorne. Vitamin D + K2 Liquid product page: supplement facts and suggested use.
- van Ballegooijen AJ, et al. The Synergistic Interplay between Vitamins D and K for Bone and Cardiovascular Health: A Narrative Review. Int J Endocrinol. 2017. PubMed 29138634
- Schurgers LJ, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007. PubMed 17158229
- Theuwissen E, et al. Low-dose menaquinone-7 supplementation improved extra-hepatic vitamin K status, but had no effect on thrombin generation in healthy subjects. Br J Nutr. 2012. PubMed 22289649
Talk with your own doctor or healthcare provider about the right dose for you before starting any supplement, especially if you’re pregnant, nursing, or take medications.
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If you have questions about whether vitamin D and K2 fits your plan, a short call is a simple place to start.
This page shares general educational information and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Talk with your healthcare provider before starting any supplement, especially if you take medications, are pregnant or nursing, or have a health condition. Product labels can change, so always follow the label on the bottle you have.
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