Best Vitamin K2 Supplement in the UK (2026): MK-7 Picks, Ranked
On Amazon.co.uk:Alpha01 Vitamin K2 MK-7 100 mcg (120 capsules). MK-7 at 100 mcg per capsule, the standard dose.
One note on verification: K2 products rarely carry a USP or NSF label-accuracy mark — so we weight the quality signals that do exist for K2: all-trans content and a branded ingredient like MenaQ7. Check the label for either.
Informational summary of published research — not medical advice. If you take warfarin or another vitamin K antagonist, do not start K2 without your physician. Picks are ranked by form quality and cost per day, never commissions.
What we list on Amazon.co.uk
| Product | Form | K2 Dose | Why this one | Buy |
|---|---|---|---|---|
| Alpha01 Vitamin K2 MK-7 100 mcg (120 capsules) | MK-7 | 100 mcg | The standard dose of MK-7 in one capsule. | Check price → |
Why MK-7 — and why "all-trans" matters
Almost every K2 buying decision comes down to one thing: choose MK-7, not MK-4. MK-7 has a long half-life, so a single 90–200 mcg daily dose reaches and holds useful blood levels; MK-4 is cleared within hours, so a low-dose MK-4 supplement is not comparable. That's why the standalone supplements worth buying are MK-7. For the full pharmacology, see MK-7 vs MK-4.
The quality wrinkle is that MK-7 comes in an active all-trans form and a much less active cis form that contaminates cheap synthetic material. Branded, fermentation-derived ingredients like MenaQ7 are marketed as guaranteeing all-trans content. Look for one on the label. A label that says "all-trans" or names its ingredient brand is a genuine quality signal; a bargain MK-7 with neither is a gamble.
What to look for
- MK-7, not MK-4 — the practical form for daily supplementation.
- All-trans, ideally branded — look for "all-trans" or a named ingredient (MenaQ7). This is the single biggest quality differentiator.
- A trial-anchored dose — 90–200 mcg MK-7. 100 mcg is the sweet spot; 300 mcg sits at the upper studied range.
- Soy-free if you're allergic — natto-derived MK-7 can carry trace soy; chickpea-fermented options avoid it.
- Pure MK-7 vs a blend — a standalone MK-7 is cleanest. Some products add K1 — the form in leafy greens your liver uses for blood clotting — plus a little MK-4 on top; that's fine if you want fuller vitamin-K coverage, but the MK-7 is the main ingredient. A D3+K2 combo is also fine if it fits your routine.
What we don't recommend
- Unbranded bargain MK-7 with no all-trans claim — you can't tell how much is the inactive cis form.
- Low-dose MK-4-only products — MK-4 doesn't accumulate at supplement doses, so it is not comparable to MK-7.
- Anything promising to "clean out" or "reverse" plaque or calcification — K2 is a nutrient, not a treatment for any condition. See the MK-7 vs MK-4 page for the form comparison.
- Starting K2 while on warfarin without your doctor — vitamin K opposes warfarin, and consistency of intake matters. This is a conversation with your prescriber, not a self-serve add-on.
Frequently Asked Questions
What is the best vitamin K2 supplement?
For most people the best vitamin K2 is a standalone all-trans MK-7 at the standard 100 mcg dose. On Amazon.co.uk we list Alpha01 Vitamin K2 MK-7 100 mcg (120 capsules): MK-7 at 100 mcg per capsule. Choose MK-7 over MK-4, and look for an all-trans label.
Should I take a D3 and K2 combo or separate supplements?
Either works. A combo is convenient. But the "45 mcg K2 per 1,000 IU D3" ratio printed on combos is a formulation convention, not a validated dose — so a combo is not medically superior to taking a 90–200 mcg MK-7 separately. Pick a combo for convenience, or separate products if you want to control each dose independently.
How much vitamin K2 should I take per day?
A trial-anchored MK-7 dose is 90–200 mcg per day; the 3-year trials used 180 mcg. The NIH has not set an upper limit for vitamin K, but talk to your doctor before starting. Take it with a fatty meal. The one hard rule: if you take warfarin or another vitamin K antagonist, do not start K2 without your physician. See our MK-7 vs MK-4 guide for the full dosing breakdown.
What does "all-trans" MK-7 mean on a label?
MK-7 exists as an active all-trans form and a much less active cis form that can contaminate cheap synthetic material. All-trans is the form used in the clinical trials and the one you want. Branded, fermentation-derived ingredients like MenaQ7 are marketed as guaranteeing all-trans content; a label that says "all-trans" or names a branded ingredient is a good quality signal.
Related Guides
- MK-7 vs MK-4 — Which form and how much
- All Vitamin K2 Guides
- Vitamin D with K2 — Whether you need the pairing
- Best Vitamin D Supplement — The other half of the combo
Sources
- Sato T, et al. "Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women." Nutr J. 2012;11:93. PMID: 23140417
- Schurgers LJ, et al. "Vitamin K-containing dietary supplements: synthetic K1 vs natto-derived MK-7." Blood. 2007;109(8):3279-83. PMID: 17158229
- Knapen MHJ, et al. "Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women." Osteoporos Int. 2013;24(9):2499-507. PMID: 23525894
- Cirilli I, et al. "Carboxylative efficacy of trans and cis MK7." Biofactors. 2022;48(5):1058-1066. PMID: 35583412
- NIH Office of Dietary Supplements. "Vitamin K: Fact Sheet for Health Professionals." ods.od.nih.gov