Vitamin D
Also known as: Vitamin D3, Cholecalciferol, Vitamin D2, Calciferol
The sunshine vitamin essential for immunity, bones, and mood
Primary Benefit
Bone Health & Immunity
Standard Dose
1,000–2,000 IU/day
Evidence
Certifications
Overview
Vitamin D is a fat-soluble vitamin that functions more like a hormone, regulating hundreds of genes in the body. Most people in northern latitudes are deficient, and supplementation has been linked to improved immunity, bone health, mood, and cardiovascular function.
Benefits & Evidence
- Supports calcium absorption and bone density
- Modulates immune system function
- May improve mood and reduce depression risk
- Associated with lower risk of cardiovascular disease
- Supports muscle function
Clinical Study Summaries
Vitamin D supplementation and cancer mortality
2019JAMA Network Open
Vitamin D3 supplementation was associated with significantly reduced cancer mortality.
View studyEffect of Vitamin D supplementation on depression
2020Journal of Affective Disorders
Vitamin D supplementation significantly reduced depression scores in deficient individuals.
Recommended Dosage
| Standard Dose | 1,000–2,000 IU/day |
| Minimum | 600 IU/day (RDA) |
| Maximum | 4,000 IU/day (safe upper limit) |
| Timing | With a fat-containing meal for best absorption |
Side Effects & Interactions
Who Should Consider It
Good candidates
- People with limited sun exposure
- Individuals living in northern latitudes (above 40°N)
- Older adults (reduced synthesis with age)
- People with darker skin tones
- Those with confirmed deficiency
Use caution or avoid
- Individuals with hypercalcemia
- Those with sarcoidosis or certain granulomatous diseases