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Ingredient

Vitamin D3 (Cholecalciferol)

Strong

A fat-soluble vitamin with widespread low intake in northern climates.

How it works

Acts via the vitamin D receptor on calcium homeostasis, bone health, and immune cell signalling.

Evidence

Endocrine Society clinical practice guideline summarizes evaluation, treatment, and prevention of vitamin D deficiency, including recommended daily intake and tolerable upper limits.

Studies

  • Holick et al., J Clin Endocrinol Metab, 2011 (Endocrine Society guideline)

    Recommends supplementation at suggested daily intake and tolerable upper limit levels (1000-4000 IU range for adults is detailed in the guideline body) and 25-hydroxyvitamin D measurement as the initial diagnostic test.

    PubMed 21646368

  • Bouillon et al., Endocr Rev, 2019

    Reviews vitamin D physiology; cites 400 IU for rickets/osteomalacia prevention and 800 IU with calcium for fracture prevention in elderly.

    PubMed 30321335

Top products

Sorted by effective monthly cost

Now Foods Vitamin D3 2000 mg

Now Foods

Per serving
2000 mg
Studied midpoint
2500 mg · 2/day

Effective cost

$0.11/day·$3/month

Nature Made Vitamin D3 2000 mg

Nature Made

Per serving
2000 mg
Studied midpoint
2500 mg · 2/day

Effective cost

$0.19/day·$6/month

Thorne Vitamin D3 1000 mg

Thorne

Per serving
1000 mg
Studied midpoint
2500 mg · 3/day

Effective cost

$0.60/day·$18/month

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