Free deliveryWhy The Wellness recommends this
Curated, not stocked.
We recommend this particular combination because the D3-plus-K2 formulation reflects how these nutrients actually function in the body — not as standalone additions, but as partners in calcium metabolism. Thorne's use of MK-4, a well-studied K2 form, is the kind of formulation decision that earns a place on our shelves. This is one of the first supplements we suggest when a patient's blood panel reveals low vitamin D.
About this product
Vitamin D and K2
Thorne Vitamin D and K2 is a combined supplement providing vitamin D3 alongside vitamin K2 in the MK-4 form. The pairing is deliberate: vitamin D3 supports calcium absorption from the gut, but without adequate vitamin K2, that calcium may not be directed efficiently to bones and teeth. K2 activates the proteins — osteocalcin and matrix Gla-protein — that guide calcium into bone and help keep it out of arterial walls. Taken together, the two nutrients work along complementary pathways.
This combination suits adults who have confirmed low vitamin D on a blood test, those with limited sun exposure — desk workers, people living at northern latitudes, or those who cover their skin for cultural or medical reasons — and anyone focused on long-term bone density, particularly women approaching or past menopause. It also fits people taking standalone vitamin D who want the added reassurance that K2 is present to direct calcium appropriately.
Thorne is a brand our clinical team returns to consistently. Their manufacturing standards and ingredient quality sit above the typical supplement category, and their formulations tend to reflect the kind of detail — like pairing D3 with MK-4 specifically — that suggests the science has been considered rather than cut to a price point. As always, a baseline vitamin D blood test before supplementing lets you know whether you actually need it and helps you track whether it is working.
What it does
Benefits
- 01
Supports calcium direction into bone, not arterial walls
- 02
D3 and K2 MK-4 paired for complementary bone metabolism
- 03
Suits those with confirmed low vitamin D or limited sun exposure
- 04
May help maintain bone density during and after menopause
- 05
Supports immune function via vitamin D3 pathway
Get the most from it
How to use
Take 1 capsule daily, as directed on the packaging. Fat-soluble vitamins like D3 and K2 are generally better absorbed when taken with a meal containing some dietary fat.
What's inside
Ingredients
View full ingredient list
Vitamin D3, Vitamin K2 (MK-4)
Common questions
Frequently asked
Why does this combine vitamin D with K2 rather than offering D alone?
Vitamin D3 increases calcium absorption, but K2 is needed to activate the proteins that direct that calcium to bone rather than soft tissue. The combination addresses both steps in the process, which is why many clinicians prefer it over D3 alone.
Should I test my vitamin D levels before starting this?
A baseline blood test is worthwhile. It confirms whether you are actually deficient, gives you a reference point to check progress, and helps a clinician determine whether a standard maintenance dose is appropriate for you or whether a higher therapeutic dose is needed.
Is this safe to take if I am on blood-thinning medication such as warfarin?
Vitamin K2 can interact with warfarin and similar anticoagulant medications by affecting clotting pathways. If you are on any anticoagulant, speak to your GP or prescribing clinician before starting this supplement.
How long before I notice a difference?
Vitamin D is a fat-soluble nutrient that builds up gradually. Blood levels typically rise over several weeks of consistent use. Bone-related benefits operate over months to years rather than days, so patience and a follow-up blood test at around three months are both sensible.
Who might not be suitable for this supplement?
People with hypercalcaemia, certain granulomatous conditions such as sarcoidosis, or primary hyperparathyroidism should avoid additional vitamin D without medical supervision. Those on anticoagulants should seek advice before taking K2, as noted above. Check with your doctor if you are pregnant or managing a chronic condition.
Doctor-guided care
Test before you supplement.
Bloods are the only way to know what your body actually needs. We'll tell you which of these supplements earn their place.
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