From the Guidelines
The recommended daily dose of Vitamin D (Cholecalciferol) is 600-800 IU for adults.
Key Considerations
- The Institute of Medicine recommends a daily dose of 600 IU for individuals from 1 to 70 years of age, and 800 IU for individuals 71 and older 1.
- The Endocrine Society and other organizations define vitamin D deficiency as levels of 25(OH)D3 < 20 ng/ml, and vitamin D insufficiency as 20 – 30 ng/ml 1.
- The safe upper limit of dietary vitamin D intake is 4000 IU daily, above which the risk of toxicity increases 1.
- Vitamin D3 (cholecalciferol) is considered more effective than vitamin D2 (ergocalciferol) in raising 25(OH)D concentrations and maintaining those levels for a longer time when longer dosing intervals are employed 1.
Dosing Regimens
- Daily dosing is not necessarily required, as 25(OH)D3 has a half-life of 2 weeks to 3 months and is stored in adipose tissue and the liver 1.
- Intermittent dosing regimens, such as 100,000 IU every 3 months, may be effective and preferred by some individuals 1.
- Summer sun exposure may provide enough vitamin D for the winter, and major institutions have used dosing schedules as infrequent as once every 1–4 months 1.
Special Populations
- Adults older than 50 years may require 800-1000 IU of vitamin D daily, in addition to 1200 mg of calcium from all sources 1.
- Dark-skinned or veiled individuals, institutionalized subjects, and those ≥ 65 years old may benefit from supplementation without baseline 25(OH)D measurement 1.
From the Research
Recommended Daily Dose of Vitamin D
The recommended daily dose of Vitamin D (Cholecalciferol) varies depending on several factors, including age, body mass index (BMI), and serum 25-hydroxyvitamin D concentration.
- A study published in the Journal of the American Board of Family Medicine in 2014 found that the average daily dose of vitamin D resulting in any increase in serum 25-hydroxyvitamin D level was 4707 IU/day 2.
- Another study published in Pharmacotherapy in 2012 suggested that vitamin D doses of 800-5000 IU/day can improve musculoskeletal health, and that a cumulative dose of at least 600,000 IU administered over several weeks may be necessary to replenish vitamin D stores 3.
- A more recent study published in In vivo in 2025 found that a daily dose of 2,000 IU of vitamin D3 can maintain vitamin D levels within the recommended range in healthy young adults, while a dose of 4,000 IU/day was more effective for maintaining levels above 100 nmol/l 4.
- A narrative review published in Nutrients in 2024 suggested that daily vitamin D supplementation using higher than normal dosing (up to the upper limit value) and intermittent (once or twice per week) dosing may be effective for preventing and treating vitamin D deficiency in patients with increased risk, such as those with obesity or multi-morbidity 5.
- A study published in The Journal of steroid biochemistry and molecular biology in 2019 found that long-term supplementation with vitamin D3 in doses ranging from 5,000 to 50,000 IUs/day appears to be safe, with no cases of vitamin D3-induced hypercalcemia or adverse events attributable to vitamin D3 supplementation 6.
Factors Affecting Vitamin D Dosage
Several factors can affect the required dose of vitamin D, including:
- Starting serum concentration of 25-hydroxyvitamin D
- Body mass index (BMI)
- Age
- Serum albumin concentration
- Presence of certain medical conditions, such as obesity or liver disease
Special Considerations
- Patients with increased risk of vitamin D deficiency, such as those with obesity or multi-morbidity, may require higher doses of vitamin D supplementation 5.
- Regular monitoring of 25-hydroxyvitamin D, calcium, and phosphorus levels is essential to ensure safe and effective vitamin D supplementation 4, 5.