Cholecalciferol, a form of vitamin D that helps the body absorb calcium and maintain normal bone mineralization.
Purpose, evidence and practical considerations.
Supplement decisions depend on age, dietary intake and clinical circumstances. Treatment of established deficiency differs from routine supplementation in otherwise healthy people.
Adequate vitamin D prevents deficiency-related bone disease. In VITAL, daily D3 did not reduce fractures in generally healthy midlife and older adults who were not selected for deficiency or osteoporosis. That result does not negate treating deficiency.
Confidence: moderate
Excess vitamin D can cause hypercalcemia, kidney stones and tissue calcification. Total intake from all products matters, and high doses should be guided by clinical context and appropriate testing.
D3 is made in skin exposed to sunlight and is available in foods and supplements. It differs from vitamin D2 and from active vitamin D medicines. A nutritional requirement does not establish a benefit from taking progressively larger amounts.
The evidence on this page does not automatically apply to:
How people use it, with their schedules, context and original sources.
10,000 IU · Morning
Immune function, hormone production, and mood support
4,000-5,000 IU · Daily
Immune, bone, mood support
2,000-5,000 IU · Daily
Immune function, metabolic health, hormone balance. Adjust based on blood levels.
4,000-5,000 IU · Daily
Immune function, hormone support
Based on blood levels · Daily
Hormone precursor, mood, and bone health
Amount and timing patterns reported in public protocols; these are observations, not instructions. Private and hidden usage is excluded.
These share a protocol with this intervention. This does not establish that they work together or are suitable alternatives.