Vitamin D3 vs Vitamin K2 (MK-7)
Vitamin vs Vitamin · evidence-backed comparison
- • Vitamin D3 has the stronger evidence base (strong (multiple rcts / meta-analyses)).
- • Vitamin D3 has the broader effect profile across the 9 effect categories.
- • Vitamin D3 is cheaper per serving ($0.08 vs $0.18).
Side-by-side traits
| Trait | Vitamin D3 | Vitamin K2 (MK-7) |
|---|---|---|
Category | Vitamin | Vitamin |
Active compound | Cholecalciferol | Menaquinone-7 |
Form available | Softgel, Capsule, Liquid, Tablet | Softgel, Capsule |
Source | animal | microbial |
Typical dose | 1000–4000 IU daily | 100–200 mcg daily |
Dose range | 1000–4000 IU | 100–200 mcg |
Loading protocol | — | — |
Best taken with | fat-containing meal | fat-containing meal |
Best time of day | morning | any |
Bioavailability How efficiently the body absorbs and utilizes the compound. | High (4/5) | High (4/5) |
Onset time | Cumulative: 8–12 weeks | Cumulative: 4–12 weeks |
Half-life | ~3 weeks | ~72 hours |
Evidence level Quality and quantity of human research. | Strong (multiple RCTs / meta-analyses) | Moderate (some RCTs) |
Overall effect Subjective effect magnitude. | Moderate (3/5) | Low (2/5) |
Muscle / strength | Moderate (3/5) | Very Low (1/5) |
Physical energy | Moderate (3/5) | Very Low (1/5) |
Focus / cognition | Low (2/5) | Very Low (1/5) |
Mood / stress | High (4/5) | Very Low (1/5) |
Sleep quality | Moderate (3/5) | Very Low (1/5) |
Immunity | Very High (5/5) | Low (2/5) |
Recovery Post-exercise recovery support. | Moderate (3/5) | Low (2/5) |
Longevity / healthspan | High (4/5) | High (4/5) |
Safety rating 5 = exceptionally well-tolerated; 1 = significant risk profile. | High (4/5) | High (4/5) |
Price per serving Approximate USD per typical daily dose. | $0.08 | $0.18 |
Vegan friendly | No | Yes |
Gluten free | Yes | Yes |
3rd-party tested | Yes | Yes |
About Vitamin D3
Most adults are deficient. Affects 1000+ genes including immunity, mood, and bone health. Pair with K2 to direct calcium into bones, not arteries.
About Vitamin K2 (MK-7)
Activates osteocalcin and matrix-Gla protein to direct calcium into bones rather than arteries. Most evidence comes from the 3-year Rotterdam study.
Vetted brands, third-party testing, ships worldwide.
Vetted brands, third-party testing, ships worldwide.
Vitamin D3 safety
Common side effects:
- • Hypercalcemia (very high doses)
Avoid if:
- • Hyperparathyroidism
- • Sarcoidosis
- • Kidney stones
Drug interactions:
- • Statins
- • Thiazide diuretics
- • Steroids
Vitamin K2 (MK-7) safety
Common side effects:
- • Generally none
Avoid if:
- • Warfarin therapy
Drug interactions:
- • Warfarin (major)
- • Other anticoagulants
Common uses
- • Deficiency correction
- • Bone health
- • Immune support
- • Mood / SAD
Stacks well with: Vitamin K2 (MK-7), Magnesium Glycinate
Common uses
- • Bone density
- • Arterial health
- • Calcium routing
Stacks well with: Vitamin D3, Magnesium Glycinate
Related comparisons
Medical disclaimer
SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements — especially if you are pregnant, breastfeeding, take prescription medication, or have a chronic condition.