Why are so many Australians low in vitamin D?
Mostly because of how we live. Sun-safe habits and indoor jobs mean less sun on bare skin, and food rarely makes up the gap. Risk is higher if you’re rarely outdoors, have naturally very dark skin or live in southern Australia, where winter UV levels are low. If that sounds like you, ask your GP about a blood test.
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. D3 depends on sun on your skin, and 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 or another vitamin D product
- You take a blood thinner such as warfarin (talk to your GP first)
- You take a statin, steroid or diuretic, as some interact with vitamin D (check with your GP or pharmacist)
- You only want to meet the recommended intake: a standard 25 microgram (1,000 IU) vitamin 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 grown under UV light.
- D3 (cholecalciferol) is the form your own skin makes in sunlight. It’s also the form found in oily fish and egg yolks.
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 labelled MK and a number.
| Form | Chemical name | Where you find it | Worth knowing |
|---|---|---|---|
| K1 | Phylloquinone | Leafy greens such as spinach, kale and broccoli; vegetable oils | The main form in most diets |
| K2 (MK-4) | Menaquinone-4 | Meat, egg yolks, butter | Your body also makes some from K1 |
| K2 (MK-7) | Menaquinone-7 | Natto (fermented soybeans); smaller amounts in some cheeses | 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: few foods contain much, and K2 is mostly found in natto, which few Australians eat.
| Nutrient | Main food sources | Worth knowing |
|---|---|---|
| Vitamin D | Oily fish (salmon, sardines, mackerel), eggs, UV-exposed mushrooms; margarine and some milks are fortified | Few foods contain much. Most Australians get most of their vitamin D from the sun |
| Vitamin K2 | Natto, some hard cheeses, egg yolks, meat | Natto is the richest source, and a rarity on Australian plates |
So if you eat well and still wonder why either matters, that’s the answer. Average vitamin D intakes from food in Australia are only 2 to 3 micrograms a day. 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 5 to 15 micrograms of vitamin D a day, depending on age, and the upper level is 80 micrograms (3,200 IU) from all sources. For vitamin K, the adequate intake is 70 micrograms for men and 60 for women.
| Nutrient | Daily amount (NHMRC) | Upper level (NHMRC) |
|---|---|---|
| Vitamin D, adults | 5–15 micrograms (200–600 IU), depending on age | 80 micrograms (3,200 IU) a day |
| Vitamin K, adults | 70 micrograms (men), 60 micrograms (women) | None set |
| KURK D3+K2 Spray, per daily serving (7 sprays) | D3: 75 micrograms (3,000 IU). K2: 150 micrograms | Just under the adult upper level for vitamin D |
More isn’t better. The upper level counts vitamin D from everything you take: food, drinks and supplements. Our spray gives you 75 micrograms a day, so check the micrograms on anything else you take, such as a multivitamin, before adding it. If you’re unsure, ask your GP or pharmacist.
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 routine, 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.
What's in the KURK D3+K2 Spray, and how is it made?
| KURK D3+K2 Spray | |
|---|---|
| Vitamin D3 per daily serving | 75 micrograms (3,000 IU) |
| Vitamin K2 per daily serving | 150 micrograms, as MK-7 |
| 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 | 30ml bottle, about 30 daily servings of 7 sprays (1ml) |
| Cost per day | About A$3.28 a day as a one-off purchase (A$98.33 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 vitamin D3 and K2 good for?
Vitamin D helps your body absorb calcium and supports normal bones and muscle function. Vitamin K helps your blood clot normally and plays a part in bone health.
Is 3,000 IU (75 micrograms) of vitamin D3 a day safe?
It’s just under the NHMRC adult upper level of 80 micrograms (3,200 IU) a day, which counts all sources. So check any multivitamin or other vitamin D you take, and ask your GP or pharmacist 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 GP 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 GP first. Vitamin K can interact with blood thinners such as warfarin, so your GP needs to know before you start anything that contains it.
Always read the label and follow the directions for use. Supplements should not replace a balanced diet. Talk to your GP or pharmacist before starting any new supplement, especially if you are pregnant, breastfeeding, taking medication or managing a medical condition.
Sources
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National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. Vitamin D and vitamin K adequate intakes, upper levels.
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Dunlop E, et al. Journal of Human Nutrition and Dietetics, 2022. doi.org/10.1111/jhn.13002. Vitamin D intakes and status in Australia.
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Nowson CA, Margerison C. Medical Journal of Australia, 2002;177(3):149–52. Vitamin D intake and vitamin D status of Australians.
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National Institutes of Health, Office of Dietary Supplements. Vitamin D: Fact Sheet for Consumers. D2 vs D3.
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National Institutes of Health, Office of Dietary Supplements. Vitamin K: Fact Sheet for Health Professionals. Food sources, warfarin.
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Schurgers LJ, Teunissen KJ, Hamulyák K, et al. Blood, 2007;109(8):3279–83. MK-7 vs K1 in the blood.
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Schurgers LJ, Vermeer C. Haemostasis, 2000;30(6):298–307. doi.org/10.1159/000054147. K1 and K2 in food.
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Aaseth JO, Finnes TE, Askim M, Alexander J. Nutrients, 2024;16(15):2420. doi.org/10.3390/nu16152420
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Better Health Channel, Victorian Government. Vitamin D. Risk groups and winter UV levels.
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