What is the recommended dose of Vitamin D (Vit D) for treating Vitamin D deficiency?

Vitamin D Supplementation for Deficiency Treatment

For treating vitamin D deficiency, adults should receive 50,000 IU weekly for 8 weeks, followed by maintenance therapy of 800-1,000 IU daily. 1

Diagnosis and Classification

Vitamin D status is determined by measuring serum 25-hydroxyvitamin D [25(OH)D] levels:

• Deficiency: <20 ng/mL (<50 nmol/L)
• Insufficiency: 20-30 ng/mL (50-75 nmol/L)
• Sufficiency: >30 ng/mL (>75 nmol/L) 2

Treatment Recommendations Based on Deficiency Severity

Initial Treatment Phase

• Mild deficiency (15-20 ng/mL): 800-1,000 IU/day 2
• Moderate deficiency (5-15 ng/mL): 50,000 IU weekly for 8 weeks 2, 1
• Severe deficiency (<5 ng/mL): Individualized treatment under close monitoring 2

Maintenance Phase

After normalization of vitamin D levels:

• Adults 19-70 years: 600-800 IU daily 2
• Adults >70 years: 800 IU daily 2
• Monitor 25(OH)D levels 3-4 months after initiating therapy 2

Special Populations Requiring Higher Doses

Certain populations may require higher vitamin D doses:

• Obesity: 2-3 times higher doses (up to 7,000 IU daily) 2, 3
• Malabsorption syndromes: 50,000 IU 1-3 times weekly 2
• Bariatric surgery patients: 3,000-6,000 IU daily 2
• Liver disease: Higher doses due to impaired hepatic 25-hydroxylation 2, 3
• Dark-skinned or veiled individuals: 800 IU/day 2
• Institutionalized individuals: 800 IU/day 2

Administration Considerations

• Take vitamin D supplements with food to enhance absorption 4
• For high-dose therapy (50,000 IU), weekly administration is recommended 4
• Avoid single large doses of 300,000-500,000 IU 5
• Ensure adequate calcium intake (1,000-1,500 mg daily) alongside vitamin D supplementation 2

Safety and Monitoring

• Upper safety limit: 4,000 IU daily for most adults 2
• Vitamin D toxicity is rare and typically occurs with prolonged intake >10,000 IU daily 2
• Monitor serum calcium and phosphorus during high-dose supplementation 2
• Contraindications: hypercalcemia, malabsorption syndrome, abnormal sensitivity to vitamin D, and hypervitaminosis D 4

Practical Approach for Clinicians

1. Measure baseline 25(OH)D level in suspected deficiency
2. Select appropriate dosing regimen based on severity
3. Recheck 25(OH)D levels after 3-4 months of therapy
4. Adjust to maintenance dose once target levels are achieved
5. Consider higher doses for high-risk populations

For patients with documented vitamin D deficiency, a cumulative dose of at least 600,000 IU administered over several weeks appears necessary to replenish vitamin D stores 5.