Vitamin D2 vs vitamin D3 efficacy
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Vitamin D2 vs Vitamin D3 Efficacy: Serum 25(OH)D Levels
Multiple studies consistently show that vitamin D3 (cholecalciferol) is more effective than vitamin D2 (ergocalciferol) at raising and maintaining serum 25-hydroxyvitamin D [25(OH)D] levels, which is the main marker for vitamin D status in the body 123456710. Large randomized controlled trials and meta-analyses have found that vitamin D3 supplementation leads to a greater and faster increase in 25(OH)D concentrations compared to vitamin D2. For example, one large trial found that vitamin D3 increased vitamin D status by 74–75%, while vitamin D2 only increased it by 33–34% at the same dose over 12 weeks . Meta-analyses also confirm that D3 is more effective than D2 across different populations, dosages, and supplementation vehicles 26.
Dosing Frequency and Efficacy Differences
The difference in efficacy between D2 and D3 is most pronounced with bolus (large, infrequent) dosing, where D3 shows a clear advantage . However, some studies suggest that with daily low-dose supplementation, the difference between D2 and D3 may be smaller, and both forms can maintain 25(OH)D levels effectively in some cases 89. Still, the majority of evidence points to D3 as the more reliable option for raising and sustaining vitamin D status 267.
Effects on Vitamin D Metabolism and Other Markers
Vitamin D2 not only raises total 25(OH)D less efficiently, but it may also suppress certain vitamin D3 metabolites in the body, potentially affecting overall vitamin D metabolism . Despite these differences in raising 25(OH)D, both D2 and D3 supplementation appear to have similar effects on other markers such as calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (PTH) levels, with no significant differences observed between the two forms in these outcomes 24.
Public Health and Supplementation Considerations
Given the greater efficacy of vitamin D3, most experts recommend D3 for supplementation and food fortification strategies, especially when the goal is to quickly and reliably improve vitamin D status in populations 126710. However, vitamin D2 remains an option for those who avoid animal-derived products, as D3 is typically not vegan-friendly .
Conclusion
In summary, vitamin D3 is generally more effective than vitamin D2 at raising and maintaining serum 25(OH)D levels, especially with higher or less frequent dosing. While both forms can improve vitamin D status, D3 is the preferred choice for most individuals and public health interventions. However, D2 may still be suitable for specific dietary needs, such as vegan diets.
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