Should you take vitamin D3 and K2 together?
You can, but not everyone needs both. Their jobs overlap. Vitamin D helps your body absorb calcium. Vitamin K plays a part in bone health. Early research suggests the two may do more for your bones together than either does alone, though results so far are mixed.
They’re also hard to get in different ways. In fall and winter, shorter days mean less sun, and less D3 made by your skin. K2 is mostly found in natto and some hard cheeses, which few of us eat. Our spray covers both, so there’s one less thing to remember.
Who shouldn’t take vitamin D3 and K2?
Skip the spray if:
- You already take a multivitamin with D and K
- You take a blood thinner such as warfarin (talk to your doctor first)
- You take a statin, steroid or diuretic, as some interact with vitamin D (check with your doctor or pharmacist)
- You only want the recommended daily amount: a plain 15 mcg (600 IU) D3 does that job
Vitamin D2 vs D3: what’s the difference?
Both are vitamin D, and both raise the vitamin D in your blood. The difference is where they come from.
- D2 (ergocalciferol) is made by plants and fungi, such as mushrooms exposed to UV light.
- D3 (cholecalciferol) is the form your own skin makes in sunlight. It’s also the form in fatty fish and egg yolks.
According to the NIH, D3 might raise blood levels higher and for longer than D2.
Most D3 is made from lanolin, the natural grease in sheep’s wool, so it isn’t vegan. Ours comes from lichen, a slow-growing organism found on rocks and trees, so it’s fully vegan.
Vitamin K1 vs K2 (and MK-4 vs MK-7): what’s the difference?
Think of vitamin K as a family name. K1 is the one on your plate most days. K2 is the rarer relative, and it comes in several forms, each labeled MK and a number.
| Form | Chemical name | Where you find it | Worth knowing |
|---|---|---|---|
| K1 | Phylloquinone | Leafy greens such as spinach, kale and broccoli; soybean and canola oil | The main form in the US diet |
| K2 (MK-4) | Menaquinone-4 | Meat, chicken, egg yolks, cheese | Your body also makes some from K1 |
| K2 (MK-7) | Menaquinone-7 | Natto (fermented soybeans) | Made by fermentation. Stays in the blood longer than K1. |
Vitamin K helps your blood clot normally and plays a part in bone health. It does this by switching on osteocalcin, a protein that binds calcium into bone. Every form of vitamin K can do this, including the MK-7 in our spray, the same form found in natto.
Which foods contain vitamin D3 and K2?
Most people get enough vitamin K from food. Vitamin D is harder: very few foods contain it naturally, and K2 is mostly found in natto, which few Americans eat.
| Nutrient | Main food sources | Worth knowing |
|---|---|---|
| Vitamin D | Fortified milk and plant milks, breakfast cereals and some orange juice; fatty fish (trout, salmon, tuna, mackerel); egg yolks | Few foods contain much naturally. Fortified foods supply most of the vitamin D in American diets |
| Vitamin K2 | Natto, cheese, egg yolks, meat and chicken | 3 oz of natto has about 850 mcg of MK-7. Most other sources have a few micrograms per serving |
So if you eat well and still wonder why either matters, that’s the answer. Unless fortified milk is a daily habit, food won’t get you far on vitamin D. And K2 comes down to how often natto makes it onto your plate.
How much vitamin D3 and K2 should you take a day?
Most adults need 15 mcg (600 IU) of vitamin D a day, or 20 mcg (800 IU) from age 71, and shouldn’t go over 100 mcg (4,000 IU) from all sources. For vitamin K, the adequate intake is 120 mcg for men and 90 mcg for women.
| Nutrient | Daily amount (NIH) | Upper limit (NIH) |
|---|---|---|
| Vitamin D, adults | 15 mcg (600 IU), or 20 mcg (800 IU) if you’re 71 or over | 100 mcg (4,000 IU) a day, from all sources |
| Vitamin K, adults | 120 mcg (men), 90 mcg (women) | None set, because of its low potential for toxicity |
| KURK D3+K2 Spray, per daily serving (7 sprays) | D3: 75 mcg (3,000 IU). K2: 150 mcg | Below the adult upper limit for vitamin D |
More isn’t better. The upper limit counts everything: food, drinks and supplements. Very high vitamin D levels almost always come from supplements, and it’s easy to overshoot by accident: a multivitamin, fortified milk and a separate vitamin D product soon add up. Check the micrograms on every label.
When and how should you take vitamin D3 and K2?
Once a day, at a time you’ll remember. The routine that lasts is the one attached to something you already do. If KURK Liquid Curcumin is already in your morning coffee, that’s your moment.
- Keep the bottles together. Put the spray next to your KURK. What you see each morning, you use.
- Pair it with breakfast. It’s a moment that happens every day, so the spray happens with it.
- Follow the label. Shake well, spray 7 times under your tongue, hold for about 60 seconds, then swallow.
- Let them arrive together. Add the spray to your cart with your next KURK order, so both arrive at once.
| KURK D3+K2 Spray | |
|---|---|
| Vitamin D3 per daily serving | 75 mcg (3,000 IU), 375% DV |
| Vitamin K2 per daily serving | 150 mcg, as MK-7, 125% DV |
| Vegan | Yes. Also soy-free and gluten-free |
| Other ingredients | Filtered water, vitamin K2 (all-trans MK-7), proprietary spice blend, vitamin D3 from lichen (cholecalciferol), peppermint essential oil, sweetener (steviol glycosides), rosemary extract, tea extract, vitamin E (alpha-tocopherol) |
| Servings per bottle | 1 fl oz (30ml) bottle, about 30 daily servings of 7 sprays (1ml) |
| Cost per day | About $2.17 a day as a one-time purchase ($65 a bottle). Subscribers pay less, and you can pause or cancel any time. |
| Bottle | Glass |
| Made at | KURK Biosciences, our ISO-certified lab in London |
From KURK Biosciences, the same London team behind KURK Liquid Curcumin. The full ingredient list is above and on the label.
FAQs
What are the benefits of vitamin D3 and K2?
Vitamin D helps your body absorb calcium and supports normal bones, muscles and immune function. Vitamin K helps your blood clot normally and plays a part in bone health.
Is 3,000 IU (75 mcg) of vitamin D3 a day safe?
It’s below the NIH adult upper limit of 100 mcg (4,000 IU) a day from all sources, but well above the 15 mcg (600 IU) most adults need. Count everything you take, including multivitamins and fortified foods, and talk to your doctor if you’re unsure.
Can I take it with KURK curcumin?
Yes. They’re separate products that fit the same moment: KURK in your morning drink, the spray with breakfast. If you take any medication, check with your doctor or pharmacist first.
Is vitamin D3 vegan?
Most isn’t, because it’s made from lanolin in sheep’s wool. Ours is: the D3 comes from lichen, and the spray is also soy-free and gluten-free.
Can you take vitamin K2 with blood thinners?
Talk to your doctor first. Vitamin K can interact with blood thinners such as warfarin (Coumadin), so your doctor needs to know before you start anything that contains it.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Always read the label and follow the directions for use. Talk to your doctor or pharmacist before starting any new supplement, especially if you are pregnant, breastfeeding, taking medication or managing a medical condition.
Sources
National Institutes of Health, Office of Dietary Supplements. Vitamin D: Fact Sheet for Consumers. Recommended amounts, upper limits, food sources, interactions.
National Institutes of Health, Office of Dietary Supplements. Vitamin K: Fact Sheet for Health Professionals. Recommended amounts, food sources, warfarin.
Aaseth JO, Finnes TE, Askim M, Alexander J. Nutrients, 2024;16(15):2420. doi.org/10.3390/nu16152420
Schurgers LJ, Vermeer C. Haemostasis, 2000;30(6):298–307. doi.org/10.1159/000054147. K1 and K2 in food.
Schurgers LJ, Teunissen KJ, Hamulyák K, et al. Blood, 2007;109(8):3279–83. doi.org/10.1182/blood-2006-08-040709. MK-7 vs K1 in the blood.
Related reading:
Turmeric vs curcumin: what’s the difference and why it matters
Does KURK work? The evidence behind 185×
