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Vitamin D3 and K2 MK7 Tablets - High Dose

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Vitamin D3 and K2 MK7 Tablets - High Dose

Daily Vitamin D3 with K2 (MK-7) tablets. Made in our GMP-certified Oxfordshire facility, every batch independently tested by RSSL. The NHS recommends a daily Vitamin D supplement for everyone in the UK during autumn and winter.

  • Every Batch Tested by RSSL
  • Made in a GMP-Certified UK Facility
  • 120 Tablets · 4 Months' Supply
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The NHS recommends a daily Vitamin D supplement for everyone in the UK during autumn and winter. Between October and early March, sunlight in the UK is generally insufficient for the skin to produce adequate Vitamin D — so adults and children over the age of 1 should consider a daily supplement of at least 10μg (400 IU).
UK-made · GMP-certified · RSSL-tested

Made in our Oxfordshire facility. Tested by RSSL.

Our Vitamin D3 + K2 (MK-7) tablets are manufactured in our own GMP-certified facility in Kidlington, Oxfordshire. Every production batch is independently tested by RSSL — an independent UK laboratory — and the Certificate of Analysis is published online with the batch number printed on your bottle.

VERIFIED
BATCH
#N1754
Certificate of Analysis
Vitamin D3 + K2 (MK-7) Tablets · 5,500 IU · 120ct
RSSL (UK)
Report P26-06812
Test date: 15 Jul 2026
Vitamin D3 (Cholecalciferol) Claim: 5,500 IU Found: 5,767 IU PASS
Heavy metals (Pb, Cd, As, Hg) Below limits Below EU limits PASS
Microbial (Salmonella, yeast, mould) Within EU spec All within spec PASS
Method: HPLC-DAD, ICP-MS & ISO detection Full report at testing.nfsupplements.co.uk

Every single batch 3rd-party tested.
Results published to our testing database.

Most supplement labels are unverified. We test every production batch independently — without exception — and publish the full Certificate of Analysis online. The batch number printed on your bottle matches the report, so you can verify the product in your hand against the lab data yourself.

Each test confirms the Vitamin D3 content matches what we declare on the label, alongside heavy metals and microbiological testing.

View test results Tested by an independent UK laboratory
What Vitamin D does

A foundation nutrient with a wide remit.

Vitamin D contributes to normal absorption and utilisation of calcium and phosphorus, to the maintenance of normal bones, teeth and muscle function, and to the normal function of the immune system.* In the UK and across northern latitudes, sunlight exposure between October and March is generally insufficient for the skin to produce adequate Vitamin D, which is why daily supplementation is widely recommended.

D3 5,500 IU Vitamin D in circulation Calcium absorption approved* Normal bones approved* Muscle function approved* Immune function approved*

Why we supplement at 5,500 IU

The NHS recommends that everyone in the UK — adults and children over the age of 1 — should consider taking a daily supplement containing 10 micrograms (400 IU) of Vitamin D, especially between October and early March, when sunlight at northern latitudes is insufficient for the skin to produce adequate Vitamin D.

Our 5,500 IU dose is deliberately above the European tolerable upper intake level for adults (100μg / 4,000 IU per day). It is intended for adults who specifically want a high-dose Vitamin D supplement rather than a general daily baseline — if you are unsure whether a dose at this level is right for you, speak to your GP or pharmacist before starting. Each tablet provides 5,500 IU of Vitamin D3 (Cholecalciferol) alongside 100μg of Vitamin K2 (Menaquinone-7).

Vitamin D contributes to the maintenance of normal bones and to the normal function of the immune system. Vitamin K contributes to normal blood clotting and to the maintenance of normal bones.*

Manufactured in our own GMP-certified facility in Kidlington, Oxfordshire, with every batch independently tested by RSSL.

Authorised health claims

What Vitamin D and Vitamin K contribute to.

Each claim below is authorised under the EU/UK retained register of permitted health claims for these nutrients (Regulation (EC) No 1924/2006, list of permitted claims under Regulation (EU) No 432/2012).

Vitamin D

Vitamin D contributes to:

Normal bones & teeth*

Vitamin D contributes to the maintenance of normal bones and to the maintenance of normal teeth.*

Normal muscle function*

Vitamin D contributes to the maintenance of normal muscle function.*

Normal immune function*

Vitamin D contributes to the normal function of the immune system.*

Calcium absorption*

Vitamin D contributes to normal absorption and utilisation of calcium and phosphorus, and to normal blood calcium levels.*

Vitamin K

Vitamin K contributes to:

Normal blood clotting*

Vitamin K contributes to normal blood clotting.*

Normal bones*

Vitamin K contributes to the maintenance of normal bones.*

How we compare

What "Vitamin D3 + K2" usually leaves out.

Most products in this category disclose two numbers — D3 IU and K2 mcg — and stop there. The quality and verification details that actually determine whether the product matches its label are rarely on the box.

NF Supplements Typical High-Street Brand Typical Online Brand
Vitamin D3 dose 5,500 IU 1,000 IU 2,000 IU
Vitamin K2 dose 100 mcg 75 mcg 100 mcg
Per-batch 3rd-party testing ✓ ✕ ✕
Tested by independent UK lab (RSSL) ✓ ✕ ✕
COA published with batch number ✓ ✕ ✕
Free from artificial colours & preservatives ✓ Varies Varies
Made in the UK ✓ Often imported Often imported
Common questions

Frequently asked.

What does the NHS recommend about Vitamin D?
The NHS recommends that everyone in the UK — adults and children over the age of 1 — should consider taking a daily supplement containing 10 micrograms (400 IU) of Vitamin D, especially during autumn and winter (October to early March), when sunlight at northern latitudes is insufficient for the skin to produce adequate Vitamin D. Pregnant and breastfeeding women, people with darker skin tones, and people who spend little time outdoors are advised to consider taking a daily supplement year-round.
Is 5,500 IU of Vitamin D safe for daily use?
The European tolerable upper intake level for Vitamin D in adults is 100 micrograms (4,000 IU) per day. Our tablet provides 5,500 IU, which is above that level, so it is intended for adults who specifically want a high-dose supplement rather than a general daily baseline. We recommend speaking to your GP or pharmacist before taking it daily over the long term. If you have kidney disease, hyperparathyroidism, sarcoidosis, or are on calcium-channel blockers, consult your GP before starting any Vitamin D supplement.
Why is Vitamin K2 (MK-7) included alongside Vitamin D3?
Our formulation pairs Vitamin D3 with Vitamin K2 (Menaquinone-7) in a single daily tablet. Vitamin K contributes to the maintenance of normal bones and to normal blood clotting.* The two nutrients are commonly taken together as a daily routine, and combining them in one tablet means one product instead of two — which is why we formulate it this way.
Is this product GMP-certified, and what does that mean?
Yes. Our tablets are manufactured in our own facility in Kidlington, Oxfordshire, which is certified to GMP — Good Manufacturing Practice. GMP is a quality framework covering everything from raw material sourcing and production hygiene to batch traceability, equipment calibration and finished product release. On top of GMP, every production batch is also independently tested by RSSL, an independent UK laboratory, and the Certificate of Analysis is published online with the batch number printed on your bottle.
Does this product contain any allergens? Is it suitable for vegans?
May contain soya. The Vitamin K2 (MK-7) is fermented from natto, a soy-based source — so the finished product carries a "may contain soya" advisory. The product is free from gluten, dairy, GMOs, artificial colours and preservatives. Vitamin D3 (Cholecalciferol) in this formulation is sourced from lanolin (sheep's wool), so this product is suitable for vegetarians but not vegans. If you require a vegan Vitamin D, please get in touch and we'll point you to a lichen-based alternative.
When is the best time of day to take it?
One tablet daily, with or without food. Vitamin D is fat-soluble, so it tends to be absorbed more efficiently when taken with a meal containing some fat. Many people prefer mornings, since Vitamin D can be mildly stimulating. Consistency matters more than the exact time of day — daily dosing builds Vitamin D blood levels gradually over 8–12 weeks.
Can I take this with my multivitamin?
Check the label of your multivitamin for its Vitamin D and Vitamin K content and add the doses together. Total daily intake from all sources should be considered against the tolerable upper intake level relevant to your circumstances (100μg / 4,000 IU per day for adults, in the absence of medical guidance suggesting otherwise).
Can children take this product?
This product is formulated for adults. The Vitamin D dose at 5,500 IU per tablet is significantly higher than the NHS recommended daily 10μg (400 IU) for children. For children, we recommend a Vitamin D product specifically formulated for the appropriate age group, or speak to your GP, pharmacist or health visitor for tailored advice.
Can pregnant or breastfeeding women take this?
The NHS recommends a daily 10μg (400 IU) Vitamin D supplement during pregnancy and while breastfeeding. Our tablet provides 5,500 IU per serving, which is significantly higher than this baseline guidance. Pregnant or breastfeeding women should consult their midwife, GP or pharmacist before starting any high-dose Vitamin D supplement. We also recommend confirming the soya advisory is acceptable based on personal allergen status.
Will this interact with blood thinners or other medication?
Vitamin K can interact with vitamin K antagonist anticoagulants such as warfarin (Coumadin). If you are on any blood-thinning medication, do not start this product without first consulting your prescribing doctor — they may want to monitor your INR. Direct oral anticoagulants (DOACs) such as apixaban or rivaroxaban work via different mechanisms and are not generally affected. If you take other prescription medication, particularly for kidney conditions, hypercalcaemia, or calcium-channel blockers, please consult your GP first.
How long until Vitamin D blood levels build up?
Vitamin D blood levels build gradually with daily intake. If you started at a low baseline, levels typically reach their new equilibrium within 8–12 weeks of consistent daily dosing. This is a long-term foundation product — most users take it daily, year-round.
What's the difference between Vitamin D2 and Vitamin D3?
Vitamin D2 (ergocalciferol) is the form found in some plants and fortified foods. Vitamin D3 (cholecalciferol) is the form your skin produces from sunlight, and the form found in animal sources. Most research and most clinical guidance favour D3 for oral supplementation. Our product uses D3.
Where is it made and what's the shelf life?
Manufactured in our GMP-certified facility in Kidlington, Oxfordshire, using globally-sourced ingredients. Shelf life is 24 months from manufacture, with the batch number and expiry date printed on the base of every bottle. The same batch number gives you access to the published RSSL Certificate of Analysis at testing.nfsupplements.co.uk.
How does the subscription work, and can I cancel anytime?
Yes — you can cancel anytime. Subscriptions auto-ship at your chosen frequency (monthly, every 3 months or every 6 months) and you save up to 40% versus a one-time purchase. You'll receive an email notification a few days before each rebill, so you'll never be charged unexpectedly — and you can pause, skip, change frequency or cancel at any time from your account dashboard. No phone calls, no retention scripts, no minimum commitment. UK shipping is free on all subscriptions.

* Authorised health claims relating to Vitamin D and Vitamin K, made under EU Regulation (EC) No 1924/2006 and the list of permitted health claims established by Commission Regulation (EU) No 432/2012 (as retained in UK law). Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Consult your GP or pharmacist before use if you are pregnant, breastfeeding, taking medication, or have a pre-existing medical condition. Keep out of reach of children. Manufactured by HD Supplements LTD, Kidlington, Oxfordshire — a GMP-certified facility — using globally-sourced ingredients. Every production batch independently tested by RSSL.