K1, K2 and Vitamin D Combinations
Vitamin K1 and K2 are different names to keep when comparing supplements. K2 may be identified more specifically as MK-4 or MK-7. On a vitamin D and K combination, record each vitamin separately, with its amount per serving. If you take warfarin, check with your prescribing team before changing vitamin K intake.
Decode the ingredient name
The NIH Office of Dietary Supplements lists these forms among those used in supplements. Use the table to recognize the wording on a panel.
| Wording on the label | Form identified |
|---|---|
| Phylloquinone or phytonadione | Vitamin K1 |
| Menaquinone-4, sometimes shortened to MK-4 | A vitamin K2 form |
| Menaquinone-7, sometimes shortened to MK-7 | A vitamin K2 form |
Keep the full name. If one product says only "K2" and another specifies MK-7, the first listing leaves a question unanswered. Ask for its complete ingredient panel before treating the two as a match.
The form name does not set your dose. Nor does it establish that one bottle is suitable for replacing another recommended by your clinician.
Read a D and K combination as two entries
A combination bottle brings both nutrients into the comparison. Beside the vitamin K form, copy its amount and unit for one labeled serving. Then create a separate vitamin D entry using that same serving size. Keep the numbers on separate lines.
This matters when replacing an existing vitamin D supplement: the proposed bottle introduces vitamin K as well. Save the current and proposed labels together so the change is visible. Our vitamin D guide explains the mcg and IU units you may encounter on the D entry.
Liquids need an additional check. A drop is not a full dropper. Copy the exact serving instruction, including any stated volume, and compare it with the directions. A bottle photograph alone cannot resolve an unclear measurement. Ask the seller for a readable panel for that exact package.
If you take warfarin
NIH warns that vitamin K can seriously interact with warfarin. A sudden increase or decrease in intake can change its effect, with risks of blood clots or bleeding. The guidance is to keep intake from food and supplements consistent.
Bring the current label and any proposed replacement to the team managing your treatment. Do not start, stop or switch vitamin K supplements on the strength of a shopping comparison. Changing from K1 to K2 still belongs in that discussion.
For the Vitamin K2 listing, request the current complete panel and directions if they are not readable. Confirm the named form and serving instruction before comparing it with the label you already have.
Sources
Checked October 15, 2026. Recheck the current product label before purchase.
This guide is educational and does not replace current product labels or advice from a qualified health-care professional.