Treatment for Vitamin D Level of 14.4 ng/mL
Start ergocalciferol (vitamin D2) 50,000 IU once weekly for 12 weeks, then transition to cholecalciferol (vitamin D3) 2,000 IU daily for maintenance. 1, 2
Understanding the Severity
Your vitamin D level of 14.4 ng/mL represents moderate to severe deficiency (below 20 ng/mL), which requires aggressive treatment to prevent complications including bone pain, muscle weakness, secondary hyperparathyroidism, and increased fracture risk. 2, 3 Levels below 15 ng/mL are associated with greater severity of secondary hyperparathyroidism and increased risk of osteomalacia. 2
Initial Loading Phase Protocol
Administer ergocalciferol 50,000 IU once weekly for 12 weeks as the standard loading regimen for deficiency at this level. 1, 2, 4 The 12-week duration (rather than 8 weeks) is appropriate because your level is below 15 ng/mL. 2
Take the weekly dose with food, preferably with the largest, fattiest meal of the day to maximize absorption, as vitamin D is fat-soluble and requires dietary fat for optimal intestinal uptake. 2, 5
This loading approach is necessary because standard daily doses would take many weeks to normalize levels—the cumulative dose of 600,000 IU over 12 weeks effectively replenishes vitamin D stores. 1, 4
Why This Specific Regimen
The standard 50,000 IU weekly regimen typically raises 25(OH)D levels by approximately 40-70 nmol/L (16-28 ng/mL), which should bring your level from 14.4 ng/mL to approximately 30-42 ng/mL. 2
Using the rule of thumb, 1,000 IU daily increases serum 25(OH)D by approximately 10 ng/mL—the weekly 50,000 IU dose is equivalent to approximately 7,000 IU daily. 2
Maintenance Phase After Loading
After completing 12 weeks, transition to cholecalciferol (vitamin D3) 2,000 IU daily for long-term maintenance. 1, 2, 4 The higher end of the maintenance range (2,000 IU rather than 800 IU) is appropriate given your significant deficiency. 4
Cholecalciferol (D3) is strongly preferred over ergocalciferol (D2) for maintenance because D3 maintains serum levels longer and has superior bioavailability, particularly with daily dosing. 1, 2, 6
Essential Co-Interventions
Ensure adequate calcium intake of 1,000-1,500 mg daily from diet plus supplements if needed—vitamin D cannot work effectively without adequate calcium. 1, 2, 4
Take calcium supplements in divided doses of no more than 600 mg at once for optimal absorption, and separate calcium from the vitamin D dose by at least 2 hours. 2, 4
Engage in weight-bearing exercise at least 30 minutes, 3 days per week to support bone health and optimize vitamin D utilization. 1, 2
Monitoring Protocol
Recheck 25(OH)D levels 3 months after starting treatment (after completing the 12-week loading phase) to assess response and guide maintenance dosing. 1, 2, 4 This timing allows serum levels to reach plateau, as vitamin D has a long half-life. 2
The target level is at least 30 ng/mL for optimal health benefits, particularly for anti-fracture efficacy, adequate PTH suppression, and optimal musculoskeletal health. 1, 2, 4
If using the weekly dosing regimen, measure levels just prior to the next scheduled dose to get the most accurate assessment. 2
Once stable at target levels, recheck annually to ensure maintenance therapy is adequate. 2
Common Pitfalls to Avoid
Do not use active vitamin D analogs (calcitriol, alfacalcidol, doxercalciferol, paricalcitol) to treat nutritional vitamin D deficiency—these bypass normal regulatory mechanisms, do not correct 25(OH)D levels, and carry higher risk of hypercalcemia. 2, 4, 6
Avoid single ultra-high loading doses (>300,000 IU) as they have been shown to be inefficient or potentially harmful, particularly for fall and fracture prevention. 1, 2
Do not stop treatment prematurely—the full 12-week loading phase is necessary to adequately replenish vitamin D stores. 2
Verify patient adherence before increasing doses for inadequate response, as poor compliance is a common reason for treatment failure. 2
Special Considerations
If you have malabsorption conditions (inflammatory bowel disease, celiac disease, post-bariatric surgery, pancreatic insufficiency), you may require intramuscular vitamin D 50,000 IU or substantially higher oral doses (4,000-5,000 IU daily) instead of standard oral supplementation. 1, 2, 4
If you have chronic kidney disease (GFR 20-60 mL/min/1.73m²), the same nutritional vitamin D replacement with ergocalciferol or cholecalciferol is appropriate, but you may need monitoring of PTH levels. 2, 4
If you are elderly (≥65 years), consider maintenance doses at the higher end (1,000-2,000 IU daily) to more effectively reduce fall and fracture risk. 1, 2
Safety Profile
Daily doses up to 4,000 IU are completely safe for adults, with some evidence supporting up to 10,000 IU daily for several months without adverse effects. 1, 2, 4
The weekly 50,000 IU regimen is well-established as safe, with no significant adverse events reported in clinical trials. 1
Vitamin D toxicity is rare and typically only occurs with prolonged daily doses exceeding 10,000 IU or serum 25(OH)D levels above 100 ng/mL. 1, 2