Best Vitamin D: The Buying Guide
Test first, D3 over D2, K2 optional in-capsule, and the NOW / Thorne split
Vitamin D shopping is easy once you have a 25(OH)D number. D3 (cholecalciferol) beats D2. 5,000 IU is a repletion-style softgel, not a forever default. This buying guide picks NOW D3 for cheap D-only and Thorne D3/K2 when you want both in one capsule.
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This content is for general informational and educational purposes only. It is not medical advice, diagnosis, or treatment. Consult a qualified healthcare provider before starting any supplement, peptide, or health protocol. Read our full health disclaimer.
Frequency
Daily with food after you know the dose
Duration
Replete, retest, then maintain
Level
Beginner
Key Takeaways
- 1Test 25(OH)D; guess-dosing 10,000 IU is how people get extra calcium they did not want
- 2D3 in oil (softgel) is the format; take with a fat-containing meal
- 3NOW 5,000 IU is the Amazon repletion bottle; Thorne D3+K2 is the combo default
- 4Read the full vitamin D guide for targets; this page is the cart
Who this is for
- ·People with a lab result and 40 bottles of D2
- ·Anyone who wants K2 in the same capsule vs separate
- ·Readers who already accept they need a retest in 8–12 weeks
D3 vs D2
Strong EvidenceCholecalciferol (D3) raises 25(OH)D more reliably than ergocalciferol (D2) in most head-to-heads. Buy D3 unless a clinician specified D2.
The K2 Question
Emerging ResearchK2 (MK-7) is the usual pair to steer calcium. Evidence is plausible, not ironclad. If you want one bottle, Thorne D3/K2 is already on the roster. If K2 is elsewhere, NOW D3 5,000 IU is the cheap solo.
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Moderate Evidence50,000 IU weekly mystery packs without labs. Gummies with 20 IU. ‘D3 + 12 other things’ kitchen-sink capsules.
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For educational purposes only. Not medical advice. Read our health disclaimer.
Sources
Key references cited in this guide. Links open the original publication or abstract.
- Evaluation, treatment, and prevention of vitamin D deficiency — Endocrine SocietyJ Clin Endocrinol Metab, 2011
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