Take with Vitamin D3 and a meal containing fat
Pinned to with food, the best window for Vitamin K2.
Take with Vitamin D3 and a meal containing fat
Fat-soluble; commonly taken alongside Vitamin D3. Best window is with food, yes food. Educational only, not medical advice.
Vitamin K2 (menaquinone) is the fat-soluble vitamin that activates osteocalcin and matrix Gla-protein, two proteins that pull calcium into bone matrix and keep it out of soft tissue like arteries. It is distinct from K1 (phylloquinone, the leafy-green form), which the body uses mostly for clotting and converts only partially to K2. Two K2 subtypes show up in supplements, MK-4 (short half-life, multiple daily doses) and MK-7 (~3-day half-life, once daily).
Fat-soluble vitamin that helps direct calcium to bones. Commonly paired with Vitamin D3.
Morning, with a fat-containing meal, ideally the same meal as your Vitamin D3. Co-ingesting them simplifies absorption and pairs the two biological signals, D3 raises calcium absorption from the gut, K2 directs that calcium toward bone. MK-7's long half-life means even if you miss a day, blood levels stay elevated, so consistency matters more than the exact hour. Splitting MK-4 across the day makes sense for that subtype only.
| Window | Fit | Note |
|---|---|---|
| Morning | Okay | Calming effect works against the day |
| Midday | Best | Fine if the preferred window is not possible |
| Evening, 1-2h before bed | Poor | May interfere with sleep |
Tap each to see why.
Commonly paired; both fat-soluble and complementary.
Take together
MK-7 in a softgel for daily use, ideally combined with D3 so you only take one pill. MK-4 is fine in research contexts but requires three to four daily doses to keep levels up and tends to cost more. All-trans MK-7 (rather than cis) is the bioactive isomer, look for that on the label. Capsules are equivalent to softgels if they contain an oil carrier.
| Form | Notes |
|---|---|
| softgel | Oil-suspended, reliable absorption for fat-soluble nutrients. |
| capsule | Standard delivery, neutral taste. |
Who takes it: People supplementing Vitamin D3 (the two work together), older adults concerned about bone density, people with low bone mineral density on a DEXA scan, and people with risk factors for arterial calcification. Anyone on warfarin (Coumadin) or another vitamin K antagonist should not take K2 without their prescribing clinician adjusting dose, K2 can interfere with anticoagulant control.
MK-7 has a longer half-life and is convenient for once-daily dosing.
Vitamin D3
Fat-soluble; pair with a meal containing fat for better absorption.
Calcium
Better tolerated with food; space from iron and zinc.
Magnesium Glycinate
Calming form of magnesium; supports wind-down.
Vitamin A
Fat-soluble; take with a meal containing fat.
Fish Oil (Omega-3)
Fat-soluble; take with a meal to reduce reflux and aid absorption.
On the science
The principles behind this guidance, solubility, circadian timing, and spacing, are explained on our science page.
OptimalNourish is strictly educational. We do not recommend dosages, diagnose conditions, or suggest treatments. Always consult a qualified healthcare professional before changing your supplement routine.
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