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Vitamin · in-depth review

Vitamin D3 (Cholecalciferol)

Vitamin D3 (Cholecalciferol)

Vitamin D supports calcium absorption, bone health, muscle function, and normal immune system function.

Also known asCholecalciferolCholecalciferol
Choose a formVitamin D2 (ergocalciferol)Cod liver oil–sourced vitamin DLanolin-sourced vitamin D3
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Why supplement?

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Supports bones and calcium absorption

Vitamin D helps the gut absorb calcium and maintains bone mineralization.

Clinical evidence: Strong
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Maintains muscle function

Adequate vitamin D helps muscles maintain normal function.

Nutrition consensus: Established
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02

How to take it

With foodTake with a meal that contains fat for better absorption
Best timeBreakfast or lunch

IU–mcg conversion: 1 mcg vitamin D = 40 IU.

General wellness15 mcg/day (600 IU) for adults; 20 mcg/day (800 IU) from age 71
Specific needsDeficiency treatment doses should follow 25(OH)D testing and a doctor's directions.

How oftenUse the recommended daily intake; the usual adult upper limit is 100 mcg (4,000 IU)/day unless a doctor advises otherwise.

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What to watch

Cautions

People with kidney disease, parathyroid disease, high blood calcium, or who take calcium-containing medicines should ask a doctor first.

Do not self-treat vitamin D deficiency with high doses; adjust using blood tests.

Common side effects

· Long-term excess may cause nausea, thirst, or constipation

Rare but important

· Toxicity can cause high blood calcium, kidney injury, and heart-rhythm problems.

Long-term dependenceNot addictive; fat-soluble vitamins can accumulate with long-term excess.

Medical disclaimerThis page is compiled by the HerbBB editorial team for general health information only. It is not a substitute for advice from a doctor, pharmacist, or other qualified clinician. If you have a health condition, take medicines, or are pregnant or breastfeeding, speak with a professional first.