Vitamin D3 (Cholecalciferol)

General health & bones

Function & benefits

It contributes to the normal absorption and use of calcium and phosphorus, the maintenance of normal bones and teeth, and the normal function of the immune system (EFSA).

Dosage & how to use

Recommended dose	1000–2000 IU (25–50 mcg) daily, or according to a blood test
Best time to take	With a meal that contains fat
Frequency	Once daily

Important warnings

The safe daily upper limit for adults set by EFSA and NIH is 4000 IU

Chronic excessive doses can lead to high blood calcium and calcification of tissues

Drug interactions

Thiazide diuretics increase the risk of high blood calcium; take it two hours apart from fat-blocking weight-loss drugs (orlistat).

Scientific references

EFSA Journal 2012;10(7):2813 (Tolerable Upper Intake Level of vitamin D)
NIH ODS: Vitamin D Fact Sheet

View in the supplements guide

Related supplements

📚 Published sources and research: European Food Safety Authority (EFSA) • National Institutes of Health (NIH - ODS) • PubMed / Cochrane databases

Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)

⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.