Head-to-head
Omega-3 (EPA/DHA) vs Vitamin D3 + K2
Omega-3 vs vitamin D: if I can only take one?
The verdict
Vitamin D — if deficiency is likely (most people).
Both have excellent all-cause mortality data. Vitamin D deficiency is more common and easier to screen via a simple blood test. Omega-3 is additive on top, especially for heart and brain.
Side by side
Pick omega-3 if…
Omega-3 (EPA/DHA)You eat fatty fish less than twice a week. Target 2–3 g combined EPA + DHA daily.
- Dose
- 1–2 g
- When
- morning
Pick vitamin D if…
Vitamin D3 + K2You live indoors, in a northern latitude, or tested low. 2,000–5,000 IU daily with K2.
- Dose
- 2000–4000 IU
- When
- morning
Or take both
The two highest-ROI 'core' supplements for most adults. Take both if budget allows.
At a glance
| Omega-3 (EPA/DHA) | Vitamin D3 + K2 | |
|---|---|---|
| Typical dose | 1–2 g | 2000–4000 IU |
| Best timing | morning | morning |
| Why | Supports heart, brain, and joint health. | Critical when sun exposure is limited; supports mood and bones. |
| Tag | core | lifestyle |
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