Where can I find a trusted vitamin D2 (ergocalciferol) supplement?

Where to Find Trusted Vitamin D2 Supplements

Vitamin D2 (ergocalciferol) is available by prescription in the United States as 50,000 IU capsules, which is the most reliable and standardized form for treating vitamin D deficiency. 1, 2

Prescription Vitamin D2 (Ergocalciferol)

• The prescription form of ergocalciferol 50,000 IU is the gold standard for vitamin D2 supplementation, as it undergoes FDA oversight for quality, purity, and accurate dosing 1, 2
• This formulation is specifically recommended in clinical guidelines for treating vitamin D deficiency, with a standard regimen of 50,000 IU once weekly for 8-12 weeks 1, 2
• Prescription ergocalciferol is available at any licensed pharmacy with a valid prescription from your healthcare provider 1, 2

Important Considerations About Vitamin D2 vs D3

However, you should be aware that vitamin D3 (cholecalciferol) is generally preferred over vitamin D2 (ergocalciferol) for supplementation. 3, 4

• Vitamin D3 has been proven more potent than vitamin D2 in raising and maintaining serum 25-hydroxyvitamin D levels in all primate species, including humans 3
• Vitamin D3 maintains serum concentrations for longer periods, particularly with intermittent dosing schedules 1, 3
• In a large systematic review of 56 randomized trials with 95,286 participants, vitamin D3 significantly decreased mortality (RR 0.94,95% CI 0.91 to 0.98), while vitamin D2 showed no mortality benefit 4
• Vitamin D2 has diminished binding to vitamin D binding protein in plasma, nonphysiologic metabolism, and shorter shelf life compared to D3 3

When Vitamin D2 May Be Preferred

• Strict vegetarians may prefer vitamin D2 as it is plant-derived, whereas vitamin D3 is animal-derived 1
• Some patients may have religious reasons for preferring plant-based supplements 1
• Prescription vitamin D2 is the standard high-dose formulation available in many countries, including Denmark and other regions where D2 is contained in all high-dose vitamin D preparations 1

Over-the-Counter Vitamin D2 Options

• Some over-the-counter vitamin D2 supplements are available, but they typically contain lower doses (400-1,000 IU) 5
• If choosing OTC vitamin D2, look for products that have been third-party tested (USP Verified, NSF Certified, or ConsumerLab.com approved) to ensure quality and accurate labeling 5
• Be aware that the quality and consistency of OTC supplements can vary significantly compared to prescription formulations 5

Critical Pitfall to Avoid

• Never confuse vitamin D2 dosing with vitamin D3 dosing - some older literature suggests vitamin D2 requires 4 times the dose of vitamin D3 for equivalent effect, though this ratio is debated 6
• Ensure your pharmacy dispenses the correct frequency (weekly vs daily) - medication errors with vitamin D2 50,000 IU have resulted in toxicity when dispensed daily instead of weekly 5
• If you have malabsorption conditions (post-bariatric surgery, inflammatory bowel disease, celiac disease), vitamin D2 may be less effective than intramuscular vitamin D3 2

Monitoring Requirements

• Regardless of which form you choose, your 25-hydroxyvitamin D levels should be measured after at least 3 months of supplementation to ensure adequate response 1, 2
• The assay used must measure both 25(OH)D2 and 25(OH)D3 if you are taking vitamin D2 supplements, as some assays only measure D3 metabolites 1