Published by Paul Thompson |
Fact-checked against peer-reviewed sources | Updated March 2026

## Side-by-Side Comparison

| Vitamin D3 | Vitamin K2
--- | --- | ---
Category | Essential Vitamins | Supplement
Description | The sunshine vitamin. Essential for immune function, bone health, mood, and longevity. Up to 42% of adults are deficient. | A popular supplement in the longevity space. Research continues to explore its full benefits.
Key Benefits | Immune support, Bone health, Mood regulation, Muscle function, Longevity | Various health benefits
Best For | Immune, Bones, Mood, Longevity | General wellness

## Best Vitamin D3 Products

Our top-rated Vitamin D3 supplements based on purity, dosage, third-party testing, and value.

1 NOW Vitamin D3 5000 IU
Editor's Choice
Price: $11.99 Serving: 5000 IU per softgel
★★★★☆ 9.3/10

Optimal daily dose for most adults. Olive oil base for absorption. Incredible value.

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2 Thorne Vitamin D/K2 Liquid
Premium
Price: $24.00 Serving: 1000 IU D3 + 200mcg K2 per drop
★★★★☆ 9.5/10

D3 + K2 together ensures calcium goes to bones, not arteries. Liquid drops for easy dosing.

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3 Sports Research Vitamin D3 + K2
Best Combo
Price: $16.95 Serving: 5000 IU D3 + 100mcg K2
★★★★☆ 9.2/10

High-potency D3 with K2 in coconut oil for absorption. Non-GMO verified.

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## Which Should You Choose?

### Vitamin D3 vs Vitamin K2 — The Verdict

Both Vitamin D3 and Vitamin K2 are valuable supplements with distinct mechanisms of action. The best choice depends on your individual health goals.

For beginners: Start with whichever aligns more closely with your primary health goal. Both are well-researched and generally safe for most adults.

For advanced users: Many longevity researchers take both. They work through different mechanisms and can complement each other in a well-designed stack.

Pro Tip: Many longevity researchers combine both Vitamin D3 and Vitamin K2 in their daily protocols. If budget allows, using both may provide complementary benefits.

### Related Questions

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