Vitamin C vs Vitamin K2 (MK-7)
Vitamin vs Vitamin · evidence-backed comparison
- • Vitamin C has the stronger evidence base (strong (multiple rcts / meta-analyses)).
- • Vitamin C has the broader effect profile across the 9 effect categories.
- • Vitamin C is cheaper per serving ($0.06 vs $0.18).
Side-by-side traits
| Trait | Vitamin C | Vitamin K2 (MK-7) |
|---|---|---|
Category | Vitamin | Vitamin |
Active compound | L-ascorbic acid | Menaquinone-7 |
Form available | Capsule, Tablet, Powder, Liquid, Gummy | Softgel, Capsule |
Source | synthetic | microbial |
Typical dose | 500–2000 mg daily | 100–200 mcg daily |
Dose range | 500–2000 mg | 100–200 mcg |
Loading protocol | — | — |
Best taken with | split doses, with food | fat-containing meal |
Best time of day | any | any |
Bioavailability How efficiently the body absorbs and utilizes the compound. | High (4/5) | High (4/5) |
Onset time | Acute and cumulative | Cumulative: 4–12 weeks |
Half-life | ~30 min (plasma) | ~72 hours |
Evidence level Quality and quantity of human research. | Strong (multiple RCTs / meta-analyses) | Moderate (some RCTs) |
Overall effect Subjective effect magnitude. | Low (2/5) | Low (2/5) |
Muscle / strength | Low (2/5) | Very Low (1/5) |
Physical energy | Low (2/5) | Very Low (1/5) |
Focus / cognition | Very Low (1/5) | Very Low (1/5) |
Mood / stress | Low (2/5) | Very Low (1/5) |
Sleep quality | Very Low (1/5) | Very Low (1/5) |
Immunity | High (4/5) | Low (2/5) |
Recovery Post-exercise recovery support. | Moderate (3/5) | Low (2/5) |
Longevity / healthspan | Moderate (3/5) | 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. | $0.06 | $0.18 |
Vegan friendly | Yes | Yes |
Gluten free | Yes | Yes |
3rd-party tested | Yes | Yes |
About Vitamin C
Essential antioxidant and collagen cofactor. Doesn't prevent colds but shortens duration; chronically high doses may blunt training adaptations.
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 C safety
Common side effects:
- • GI upset (high doses)
- • Diarrhea (>2000 mg)
- • Kidney stones (predisposed)
Avoid if:
- • Hemochromatosis
- • G6PD deficiency
- • Kidney stones
Drug interactions:
- • Iron (boosts absorption)
- • Chemotherapy
Vitamin K2 (MK-7) safety
Common side effects:
- • Generally none
Avoid if:
- • Warfarin therapy
Drug interactions:
- • Warfarin (major)
- • Other anticoagulants
Common uses
- • Immune support
- • Collagen synthesis
- • Antioxidant
- • Iron absorption
Stacks well with: Zinc, Collagen Peptides
Common uses
- • Bone density
- • Arterial health
- • Calcium routing
Stacks well with: Vitamin D3, Magnesium Glycinate
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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.