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Vitamin B12 vs Vitamin K2 (MK-7) — Which Should You Take?

B12 and K2 serve entirely different functions. B12 is essential for energy and nervous system. K2 directs calcium to bones. Both are commonly deficient and important to supplement.

Quick Verdict

B12 for energy and nerve health; K2 for bone and cardiovascular health

Vitamin B12

vitamins

Typically £8–£25/month

Vitamin K2 (MK-7)

vitamins

Typically £8–£25/month
Feature
Vitamin B12
Vitamin K2 (MK-7)
Typical Dosage
500-1,000mcg daily
100-200mcg MK-7 daily
Best Form
Methylcobalamin
MK-7 (Menaquinone-7)
Key Benefits
5 listed
5 listed
Evidence Rating
★★★★
★★★★
Best Time
Morning — may be energising
With a fat-containing meal, ideally with Vitamin D3
Upper Limit
No established upper limit (water-soluble)
500mcg daily
Side Effects
2 noted
2 noted

Vitamin B12 Benefits

Energy production
Nerve function and protection
Red blood cell formation
DNA synthesis
May reduce homocysteine levels

Vitamin K2 (MK-7) Benefits

Bone mineralisation
Cardiovascular protection (reduces arterial calcification)
Works synergistically with Vitamin D3
Dental health
May reduce fracture risk

Vitamin B12 Side Effects

Very safe — excess excreted in urine
Rare: acne at very high doses in some individuals

Vitamin K2 (MK-7) Side Effects

Very safe at recommended doses
No known toxicity

Can You Take Vitamin B12 and Vitamin K2 (MK-7) Together?

In most cases, Vitamin B12 and Vitamin K2 (MK-7) can be taken together safely. However, always check the interactions section of each supplement and consult a healthcare professional if you take medication or have existing health conditions.

Vitamin B12: Metformin reduces B12 absorption — supplement if on metformin

Vitamin B12: Proton pump inhibitors (PPIs) reduce absorption

Vitamin K2 (MK-7): Warfarin/blood thinners — K2 can reduce anticoagulant effect. Consult doctor.

Vitamin K2 (MK-7): Synergistic with Vitamin D3 — take together

Which Should You Choose?

B12 for energy and nerve health; K2 for bone and cardiovascular health. Many people take both as they target different aspects of health. The best choice depends on your individual needs, existing diet, and health goals. If in doubt, start with one, assess for 4-8 weeks, then consider adding the other.

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Frequently Asked Questions

Is Vitamin B12 better than Vitamin K2 (MK-7)?

B12 for energy and nerve health; K2 for bone and cardiovascular health

Can I take Vitamin B12 and Vitamin K2 (MK-7) together?

In most cases, yes. Vitamin B12 and Vitamin K2 (MK-7) can be taken together safely. However, always check for specific interactions and consult a healthcare professional if you take medication.

What is the best time to take Vitamin B12?

Morning — may be energising

What is the best time to take Vitamin K2 (MK-7)?

With a fat-containing meal, ideally with Vitamin D3

What are the side effects of Vitamin B12?

Very safe — excess excreted in urine. Rare: acne at very high doses in some individuals.

What are the side effects of Vitamin K2 (MK-7)?

Very safe at recommended doses. No known toxicity.

How We Compare Supplements

This comparison is based on published clinical research, peer-reviewed studies from PubMed, and established nutritional science. We evaluate dosages based on clinically-effective amounts, not manufacturer recommendations. Benefits listed have at least moderate evidence from human studies. When evidence is limited or conflicting, we note this.

Disclaimer: This comparison is for educational purposes only and is not medical advice. Always consult a qualified healthcare professional before starting any supplement, especially if you take medication or have existing health conditions.

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