Vitamin D3 + K2
2,000-5,000 IU vitamin D3 daily with K2 (MK-7). Most people are deficient, and optimal levels (40-60 ng/mL) support immune function, bone health, and mood.
Dosage & Timing
Evidence Strength
4/5 — StrongStrong evidence for correcting deficiency. Benefits clear for bone health, immune function, and mood. Optimal serum level debate ongoing (40-60 ng/mL generally recommended).
Overview
Supplement with vitamin D3 (2,000-5,000 IU/day) paired with vitamin K2 (MK-7, 100-200mcg/day). Most people in northern latitudes are deficient. Vitamin D affects immune function, bone health, mood, and hundreds of gene pathways. K2 ensures proper calcium routing.
How To Do It
Get tested
Measure 25(OH)D blood level. Target 40-60 ng/mL.
Start supplementing
2,000 IU/day if mildly low, 5,000 IU/day if significantly deficient (<30 ng/mL).
Add K2 (MK-7)
100-200mcg of vitamin K2 (MK-7 form) daily to direct calcium to bones, not arteries.
Retest in 3 months
Adjust dose based on follow-up blood work.
The Evidence
Each claim is linked to its source study. Confidence reflects the study design — systematic reviews and RCTs rank highest.
Vitamin D and mortality: meta-analysis of individual participant data↗
Vitamin D status and supplementation evidence are strongest for deficiency correction and skeletal outcomes.
Primary Literature
Who Popularized This
Interactions & Warnings
Contraindications
- ⚠Hypercalcemia
- ⚠Granulomatous diseases (sarcoidosis)
Interactions
- •Take with a fat-containing meal for absorption
- •K2 prevents calcium misrouting from high D3
Measurable Outcomes
Related Protocols
Magnesium (Glycinate/Threonate)
200-400mg elemental magnesium daily. Half the population is deficient in this mineral involved in 300+ enzymatic processes including sleep, muscle function, and mood.
Foundational Supplement Stack
The essentials: D3+K2, Magnesium, Omega-3, and Creatine. These four address the most widespread deficiencies with the strongest evidence bases.
Creatine Monohydrate
3-5g daily of the most researched supplement in sports science. Benefits extend beyond muscle to cognition, bone health, and potentially neuroprotection.
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