Reviewed by Rishi Modi, Clinical Nutritionist & Founder, HealthyHey Nutrition · Last updated 25 October 2026
HealthyHey makes the D3 and K2 products named in this guide. Doses are checked against India's RDA and the research is linked, so you can check it yourself.
If you take vitamin D3 for bone health, you have probably seen it sold with vitamin K2. The two do different jobs in how the body uses calcium: D3 helps you absorb it from food, and K2 activates osteocalcin, a bone protein that binds it.
This guide explains what each does, how much India's RDA advises, what the research shows and who should check with a doctor first. For more on K2 itself, see our complete vitamin K2 guide.
Key Takeaways
- Why both: without enough vitamin D, the body absorbs only 10 to 15% of the calcium in food (Holick 2007); vitamin K2 activates osteocalcin, a bone protein that binds calcium (Schurgers 2007). Together they support calcium utilisation and bone health.
- Dose: India's RDA for adults is 600 IU (15 mcg) of vitamin D and 55 mcg of vitamin K a day (ICMR-NIN 2020). If a blood test shows low vitamin D, your doctor sets a higher dose for a period. The NHS advises not taking more than 4,000 IU (100 mcg) of vitamin D a day unless a doctor advises it.
- Timing: Both are fat-soluble, so take them together with a meal containing some fat (nuts, ghee or oil); morning or evening makes no difference, daily consistency does.
- India context: studies across India report vitamin D deficiency in 70% or more of people tested (Ritu and Gupta 2014), and natto, the richest food source of MK-7, is rarely eaten in India.
- The research: the largest MK-7 trial gave 244 healthy postmenopausal women 180 mcg a day for three years; bone loss at the spine and the neck of the hip was smaller than with a placebo (Knapen 2013).
- Safety: K2 can interact with warfarin and other anticoagulants; anyone on blood thinners, with kidney issues, high blood calcium or sarcoidosis should consult a doctor before supplementing.
What Vitamin D3 Does
Vitamin D3 helps your gut absorb calcium from food. Without enough vitamin D, the body absorbs only 10 to 15% of dietary calcium (Holick 2007). Your skin makes vitamin D in sunlight and a little comes from food; a 25-hydroxy vitamin D blood test shows your level.
What Vitamin K2 Does
Vitamin K2 activates proteins that need vitamin K to work (Schurgers 2007):
1. Osteocalcin (in bone)
Osteocalcin is made by osteoblasts, the cells that build bone. Until vitamin K activates it, through a process called carboxylation, it cannot bind calcium. In a head-to-head study, MK-7 activated osteocalcin more completely than vitamin K1 (Schurgers 2007).
2. Matrix Gla protein (MGP)
MGP is made in cartilage and blood vessel walls and also needs vitamin K. Research on what K2 supplements do there is still developing, so this guide sticks to bone health and calcium utilisation, the uses our products are labelled for.
How the nutrients fit together
| Nutrient | Role in how the body uses calcium |
|---|---|
| Vitamin D3 | Helps the gut absorb calcium from food |
| Vitamin K2 | Activates vitamin K-dependent proteins, such as osteocalcin in bone |
| Calcium | The mineral itself, a main part of bone |
| Magnesium | Needed by the enzymes that convert vitamin D into its active form (Uwitonze and Razzaque 2018) |
India's RDA sets a daily amount for all four (ICMR-NIN 2020).
Benefits of Taking D3 and K2 Together
1. Supports bone health
Vitamin D helps the body absorb the calcium bone is built from (Holick 2007). For K2: the largest MK-7 trial gave 244 healthy postmenopausal women 180 mcg of MK-7 a day or a placebo for three years. Vitamin K status improved, and bone loss at the spine and the neck of the hip was smaller with MK-7, though not across the whole hip (Knapen 2013).
2. Supports calcium utilisation
D3 helps you absorb calcium, and K2 activates osteocalcin, the bone protein that binds it (Schurgers 2007).
3. One capsule instead of two
If you need both, a combined capsule is simpler. To compare products, work out the cost per 100 mcg of K2 and per 1,000 IU of D3 rather than the bottle price.
The India Factor: Vitamin D and K2 in Indian Diets
Studies across India report vitamin D deficiency in 70% or more of people tested (Ritu and Gupta 2014).
K2 (MK-7) intake is also likely to be low, because the richest food source, natto, is not part of the Indian diet, and paneer, unlike aged cheese, is not a notable source.
If you spend little time in the sun or eat few fermented foods, a vitamin D blood test is a sensible first step. Your doctor can tell you whether you need a supplement, and how much.
D3+K2 Dosage Guide
| Group | Vitamin D3 | Vitamin K | Source |
|---|---|---|---|
| Adults (India's RDA) | 600 IU (15 mcg) a day | 55 mcg a day | ICMR-NIN 2020 |
| Low vitamin D on a blood test | A higher dose for a period, set by your doctor | Ask your doctor | Recheck as your doctor advises |
| Main MK-7 bone trial | — | 180 mcg of MK-7 a day for three years | 244 healthy postmenopausal women (Knapen 2013) |
| Upper amount from supplements | Not more than 4,000 IU (100 mcg) a day unless a doctor advises it | 1 mg (1,000 mcg) or less a day is unlikely to cause harm | NHS (vitamin D, vitamin K) |
Key points:
- Both are fat-soluble — take them with food containing fat (a handful of nuts, ghee, or a meal with oil)
- They can be taken at the same time — morning or evening, consistency matters most
- Add up the vitamin D from every supplement you take, including multivitamins, and keep the total within your doctor's advice
Can You Take D3 and K2 as a Single Supplement?
Yes. If you need both, a combined capsule means one capsule a day instead of two.
HealthyHey Vitamin K2 MK-7 + Vitamin D3 gives 55 mcg of K2 as MK-7 and 600 IU (15 mcg) of lichen-derived D3 in one vegetarian capsule a day: 100% of India's RDA for both, as printed on the label. It gives less K2 than the 180 mcg used in the main bone trial. Every production batch is tested at an NABL-accredited lab, and our published reports list their batch numbers. It is made under an FSSAI licence in a unit certified to GMP (TÜV India), FSSC 22000 and ISO 22000. See the product →
If you also want calcium and magnesium, the BoneMax complex has calcium, magnesium, D3 and K2 in one formula; take it instead of a separate D3+K2, not as well as one.
HealthyHey Vitamin K2 MK-7 + Vitamin D3: label and lab results
- Label: 55 mcg vitamin K2 (MK-7) and 15 mcg (600 IU) vitamin D3 (cholecalciferol from lichen) per vegetarian capsule; one capsule a day with a meal; 30, 60 or 120 capsules; labelled suitable for vegetarians. Other ingredients: bulking agent (INS 460(i)), anticaking agent (INS 341(iii)), vegetable capsule shell (HPMC, INS 464), binding agent (INS 407) and preservative (INS 261(i)).
- Price on healthyhey.com on 25 October 2026: ₹899 for 120 capsules (₹13.62 per 100 mcg of K2), ₹699 for 60 and ₹499 for 30.
- Lab reports (report page): heavy metals on batch PHS31122802 (Avon Food Lab, NABL TC-11151, issued 30 January 2026): lead and arsenic below the quantitation limit of 0.05 mg/kg, within FSSR 2011 limits. Microbiology on batch PHS73SA0094 (Avon, issued 7 August 2025): Salmonella and Listeria absent in 25 g. Neither report measures the K2 or D3 content.
Safety and Interactions
At India's RDA amounts, D3 and K2 are well within the NHS upper amounts. Specific cautions:
- Warfarin users — K2 can interfere with warfarin (a blood thinner). Do not take K2 supplements without your doctor's guidance if you're on anticoagulants: one study found that 50 mcg a day or more of MK-7 may change how these medicines work (Schurgers 2007).
- Kidney disease — If you have impaired kidney function, calcium metabolism is already altered. Consult your nephrologist before supplementing D3 or K2.
- Hypercalcaemia — If your blood calcium is already high, adding D3, which helps the body absorb calcium, needs medical supervision.
- Sarcoidosis / granulomatous diseases — These conditions can cause the body to produce excess active vitamin D. Consult a specialist.
If you take any medicine regularly, ask your doctor before adding D3 or K2.
Frequently Asked Questions
Why should I take vitamin D3 and K2 together?
They do different jobs in how the body uses calcium. Vitamin D3 helps you absorb calcium from food (without enough vitamin D, only 10 to 15% is absorbed), and vitamin K2 activates osteocalcin, a bone protein that binds calcium. India's RDA lists both, and one capsule with both is simpler if you need both.
Can I take vitamin D3 without K2?
Yes. Vitamin D3 helps you absorb calcium whether or not you take K2. Whether you also need K2 is worth asking your doctor: it does a different job, activating osteocalcin in bone, and India's RDA for vitamin K is 55 mcg a day.
What time of day should I take D3 and K2?
Any time of day works. Both vitamins are fat-soluble, so take them with a meal containing some fat. Taking them at the same time each day matters more than morning or evening.
Can I take D3+K2 with calcium and magnesium?
Yes. They are often taken together for bone health, and magnesium is needed by the enzymes that activate vitamin D. If a product already contains D3 and K2, such as BoneMax, do not add a second D3+K2 without checking the total with your doctor.
How do I know if I'm deficient in vitamin D?
A 25-hydroxy vitamin D blood test is the standard check. Many labs report below 20 ng/mL as deficient, but cut-offs vary between labs and guidelines, so ask your doctor what your result means. Studies across India report deficiency in 70% or more of people tested, so a test is worthwhile if you haven't had one recently.
Is the HealthyHey K2+D3 suitable for vegetarians?
Yes. HealthyHey Vitamin K2 MK-7 + Vitamin D3 comes in vegetarian capsules, its vitamin D3 comes from lichen, and the label states it is suitable for vegetarians.
Research Sources
- Holick MF. Vitamin D deficiency. N Engl J Med. 2007;357(3):266-281. doi:10.1056/NEJMra070553
- Schurgers LJ et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007;109(8):3279-3283. doi:10.1182/blood-2006-08-040709
- Knapen MHJ et al. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women. Osteoporos Int. 2013;24(9):2499-2507. doi:10.1007/s00198-013-2325-6
- Ritu G, Gupta A. Vitamin D deficiency in India: prevalence, causalities and interventions. Nutrients. 2014;6(2):729-775. doi:10.3390/nu6020729
- Uwitonze AM, Razzaque MS. Role of magnesium in vitamin D activation and function. J Am Osteopath Assoc. 2018;118(3):181-189. doi:10.7556/jaoa.2018.037
- ICMR-National Institute of Nutrition. Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements, 2020.
- NHS. Vitamins and minerals: vitamin D. nhs.uk
- NHS. Vitamins and minerals: vitamin K. nhs.uk
Disclaimer: This content is for informational purposes only and is not a substitute for professional medical advice. Consult your healthcare provider before starting any supplement. HealthyHey products are not intended to diagnose, treat, cure, or prevent any disease.