Tested and ranked — updated January 2025
| # | Product | Form | Score | Price | Action |
|---|---|---|---|---|---|
| 1 | Thorne Vitamin D3 + K2 LiquidBest Overall | Liquid drops | 9.5/10 | $26 | Buy Now → |
| 2 | NatureWise D3 5000 IU SoftgelsBest Value | Softgel | 8.8/10 | $15 | View → |
| 3 | Sports Research Vitamin D3 + K2Runner-Up | Softgel | 8.5/10 | $20 | Buy Now → |
| 4 | NOW Foods Vitamin D3 1000 IUBudget Pick | Softgel | 7.9/10 | $8 | View → |
| 5 | Nordic Naturals D3 + K2 + Omega-3 BundleBundle Pick | Softgel | 9.0/10 | $55 | Buy Now → |
| 6 | Nature Made Vitamin D2 Tablets | Tablet | 5.8/10 | $7 | View → |
An estimated 42% of American women are vitamin D deficient, and the number is even higher for women with darker skin tones. Yet most vitamin D supplements use the inferior D2 form or pair it with filler-heavy formulations. We found the ones that actually raise your levels.
We tested 10 vitamin D supplements over 6 weeks, prioritizing D3 (cholecalciferol) over D2, added K2 for calcium metabolism, third-party testing, and appropriate dosing for women (1000–5000 IU). We also evaluated lipid-based delivery systems, since vitamin D is fat-soluble and absorbs poorly without fat.
SCORING CRITERIA
Thorne
WHO IT'S FOR
The most efficient vitamin D delivery we've found.
“The most efficient vitamin D delivery we've found.”
NatureWise
WHO IT'S FOR
Unbeatable value for year-round vitamin D support.
“Unbeatable value for year-round vitamin D support.”
Sports Research
WHO IT'S FOR
Well-formulated D3+K2 in an absorbable carrier.
“Well-formulated D3+K2 in an absorbable carrier.”
NOW Foods
WHO IT'S FOR
Simple, affordable D3 for daily maintenance.
“Simple, affordable D3 for daily maintenance.”
Nordic Naturals
WHO IT'S FOR
The ultimate fat-soluble vitamin stack.
“The ultimate fat-soluble vitamin stack.”
Nature Made
WHO IT'S FOR
D2 is the wrong form — avoid despite the low price.
“D2 is the wrong form — avoid despite the low price.”
SIDE-BY-SIDE COMPARISON
| Feature | ThorneVitamin D3 + K2 Liquid | NatureWiseD3 5000 IU Softgels | Sports ResearchVitamin D3 + K2 | NOW FoodsVitamin D3 1000 IU |
|---|---|---|---|---|
| Score | 9.5/10 | 8.8/10 | 8.5/10 | 7.9/10 |
| Price | $26 | $15 | $20 | $8 |
| Format | Liquid drops | Softgel | Softgel | Softgel |
| Top Pro | D3 + K2 synergy | Excellent value (360 count) | Coconut oil carrier for absorption | Extremely affordable |
| Top Con | Requires consistent use of dropper | No K2 included | Only 60-day supply | No K2 pairing |
HOW WE SCORE
D3 (cholecalciferol) strongly preferred over D2 (ergocalciferol)
Vitamin K2 ensures calcium goes to bones, not arteries
Fat-based carrier (oil, softgel) for this fat-soluble vitamin
1000–5000 IU range with clear labeling
Cost per daily serving
FREQUENTLY ASKED
D3 (cholecalciferol) is the form your skin naturally produces from sunlight and is 87% more effective at raising blood levels than D2. Always choose D3.
The RDA is 600 IU, but most functional medicine practitioners recommend 1000–4000 IU daily, depending on your blood levels. Get tested first if possible.
Yes. Vitamin K2 directs calcium (mobilized by vitamin D) into bones and teeth instead of soft tissues and arteries. MK-7 is the preferred K2 form for its longer half-life.
Most women cannot, especially those living above 37°N latitude, working indoors, or with darker skin. Supplementation is the most reliable way to maintain optimal levels (40–60 ng/mL).
With your largest meal containing fat, as vitamin D is fat-soluble. Morning or afternoon — avoid evening doses, as some research suggests it may interfere with melatonin production.
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