Vitamin d2 versus vitamin d3 efficacy
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Vitamin D2 vs. Vitamin D3 Efficacy: Serum 25(OH)D Levels
Multiple studies have compared the effectiveness of vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) in raising serum 25-hydroxyvitamin D [25(OH)D] levels, the main marker of vitamin D status. The majority of research consistently shows that vitamin D3 is more effective than vitamin D2 at increasing serum 25(OH)D concentrations in both short-term and long-term supplementation scenarios 12356789. For example, large randomized controlled trials and meta-analyses have found that vitamin D3 supplementation leads to a greater and faster increase in vitamin D status compared to vitamin D2, with D3 being more than twice as effective in some cases 125678.
Supplementation Dosage, Frequency, and Population Differences
The difference in efficacy between D2 and D3 is observed across various dosages, supplementation vehicles (such as food fortification or capsules), and diverse populations, including different ethnic groups and age ranges 156. Some studies note that the difference in efficacy is smaller at lower doses, but D3 still remains superior overall . Additionally, both forms are effective at raising vitamin D levels, but D2 consistently results in a smaller increase compared to D3 1235678.
Impact on Other Metabolic Markers
While vitamin D3 is more effective at raising serum 25(OH)D, studies show that there are no significant differences between D2 and D3 in their effects on other metabolic markers such as calcium, phosphorus, alkaline phosphatase, or parathyroid hormone (PTH) levels after supplementation 25. This suggests that while D3 is preferable for improving vitamin D status, both forms may have similar effects on bone and calcium metabolism.
Exceptions and Study Variability
A few studies have reported that daily supplementation with equal doses of D2 and D3 can result in similar increases in serum 25(OH)D, especially at lower doses and with daily dosing regimens 410. However, these findings are less common and often come from studies with smaller sample sizes or specific dosing protocols. Most large-scale and well-powered studies support the greater efficacy of D3 12356789.
Implications for Public Health and Fortification Strategies
Given the consistent evidence favoring vitamin D3, many experts recommend D3 as the preferred form for supplementation and food fortification to address vitamin D deficiency at the population level 1569. However, considerations such as dietary restrictions (e.g., veganism) and cost may influence the choice between D2 and D3 in certain contexts .
Conclusion
In summary, vitamin D3 is generally more effective than vitamin D2 at raising and maintaining serum 25(OH)D levels across different populations, dosages, and supplementation methods. While both forms can improve vitamin D status, D3 is the preferred choice for most individuals and public health interventions. However, both D2 and D3 have similar effects on other metabolic markers, and the choice may also depend on individual dietary needs and preferences.
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