From the Guidelines
For vitamin D replacement, I recommend starting with 50,000 IU of vitamin D3 (cholecalciferol) once weekly for 8-12 weeks, followed by maintenance therapy of 1,000-2,000 IU daily, as this approach is supported by the most recent and highest quality study 1.
Key Considerations
- The goal of vitamin D replacement is to achieve and maintain a serum 25(OH)D level of at least 30 ng/mL, as recommended by the NCCN task force report 1.
- Vitamin D3 (cholecalciferol) is preferred over vitamin D2 (ergocalciferol) due to its higher efficacy in raising and maintaining 25(OH)D levels 1.
- The initial replacement phase with high-dose vitamin D3 (50,000 IU weekly) is necessary to rapidly correct deficiency, especially in severe cases (levels <10 ng/mL) 1.
- Maintenance therapy with lower doses (1,000-2,000 IU daily) is essential to sustain adequate 25(OH)D levels and prevent deficiency recurrence 1.
Important Details
- Take vitamin D supplements with meals containing some fat to enhance absorption.
- Calcium supplementation (1,000-1,200 mg daily) may be beneficial alongside vitamin D therapy, especially for those at risk for osteoporosis.
- Monitor vitamin D levels periodically to adjust the maintenance dose accordingly and prevent toxicity.
- Vitamin D is essential for calcium absorption, bone health, immune function, and possibly cardiovascular health, but high-quality evidence is limited for its role in preventing immune-related and infectious diseases, cardiovascular disease, and cancer 1.
From the Research
Vitamin D Replacement Schedule
The recommended Vitamin D (Cholecalciferol) replacement schedule varies depending on the level of deficiency and individual factors such as BMI.
- A moderate-fast-loading schedule of 60,000 IU per week for 5 weeks can effectively achieve target 25(OH)D levels over 30 ng/mL for all deficient subjects, regardless of their BMI 2.
- A loading treatment involving a total dose of 300,000 IU administered over 5 or 10 weeks is effective for repletion and does not lead to 25(OH)D overload or pose additional risks of hypercalcemia or hypercalciuria 2.
- Maintenance dosages of cholecalciferol (vitamin D3) at 800 to 1,000 IU per day from dietary and supplemental sources are recommended after vitamin D levels normalize 3.
- A combination of the loading treatment with a subsequent maintenance dose of 2000 IU daily is adequate to achieve the target vitamin D levels 2.
- High-dose oral vitamin D regimens, such as a 10-day course of D3 500,000 IU, can rapidly and effectively normalize 25(OH)D levels 4.
Factors Influencing Replacement Schedule
- BMI: Overweight and obese patients may require higher doses to reach the same vitamin D levels 2.
- Level of deficiency: More severe deficiencies may require higher doses or longer treatment durations 3, 4.
- Individual response: Patients may respond differently to various vitamin D supplementation regimens, and monitoring of 25(OH)D levels is necessary to adjust the replacement schedule as needed 5, 6.