Difference between vitamin d2 and d3
Pro Research Analysisby 
Searched over 200M research papers
Differences Between Vitamin D2 and D3
Introduction to Vitamin D Forms
Vitamin D is essential for maintaining healthy bones and supporting the immune system. It exists in two primary forms: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). Despite their similar roles in the body, research indicates significant differences in their efficacy and biological impact.
Potency and Efficacy of Vitamin D2 vs. D3
Vitamin D3 is More Potent
Multiple studies have demonstrated that Vitamin D3 is more effective than Vitamin D2 in raising and maintaining serum 25-hydroxyvitamin D [25(OH)D] levels. For instance, a study comparing the two forms found that Vitamin D3 increased serum 25(OH)D levels by 45 ng/ml, whereas Vitamin D2 only increased it by 24 ng/ml over a 12-week period 1. Another meta-analysis confirmed that Vitamin D3 supplementation had a significantly greater effect on raising serum 25(OH)D concentrations compared to Vitamin D2 2.
Long-Term Efficacy
Long-term studies also support the superior efficacy of Vitamin D3. Research conducted over the winter months showed that daily supplementation with Vitamin D3 was more effective in maintaining serum 25(OH)D levels compared to Vitamin D2 9. Participants receiving Vitamin D3 maintained stable 25(OH)D levels, while those on Vitamin D2 experienced a significant decline.
Biological Activity and Metabolism
Differential Metabolic Effects
Vitamin D2 and D3 also differ in their metabolic pathways. Vitamin D3 supplementation increases the levels of various metabolites, including 25(OH)D3, 24R,25(OH)2D3, and 1α,25(OH)2D3, more effectively than Vitamin D2 4. Conversely, Vitamin D2 has been shown to reduce the 25-hydroxylation of Vitamin D3, which may explain its lower efficacy in raising total 25(OH)D levels 4.
Storage and Bioavailability
Vitamin D3 is stored more efficiently in the body compared to Vitamin D2. A study found that Vitamin D3 resulted in 2- to 3-fold greater storage in subcutaneous fat than Vitamin D2 1. This greater storage capacity likely contributes to the sustained higher serum levels of 25(OH)D with Vitamin D3 supplementation.
Clinical Implications
Supplementation Recommendations
Given the evidence, Vitamin D3 is generally recommended over Vitamin D2 for supplementation. Its greater potency, better storage, and more effective metabolism make it the preferred choice for correcting Vitamin D deficiency 1249. However, some studies suggest that at equivalent doses, Vitamin D2 can still maintain serum 25(OH)D levels effectively, though not as robustly as Vitamin D3 10.
Considerations for Specific Populations
While Vitamin D3 is more effective overall, the choice between D2 and D3 may also depend on individual health conditions, dietary restrictions, and specific medical advice. For instance, some individuals may prefer Vitamin D2 due to dietary preferences or restrictions, such as veganism, since D2 is plant-derived.
Conclusion
In summary, Vitamin D3 is more potent and effective than Vitamin D2 in raising and maintaining serum 25(OH)D levels. It is better stored in the body and has a more favorable impact on vitamin D metabolism. Therefore, Vitamin D3 is generally the preferred form for supplementation to correct and maintain adequate vitamin D levels.
Sources and full results
Most relevant research papers on this topic
Vitamin D(3) is more potent than vitamin D(2) in humans.
D3 is 87% more potent in raising and maintaining serum 25(OH)D concentrations and produces 2- to 3-fold greater storage of vitamin D than equimolar D2, making it the preferred treatment option for vitamin D deficiency.
RCT
Very Rigorous Journal
Highly CitedComparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis
Vitamin D3 supplementation is more effective at raising serum 25-hydroxyvitamin D concentrations than vitamin D2, potentially making it the preferred choice for supplementation.
Meta-AnalysisVery Rigorous JournalHighly CitedBioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial.
Vitamin D3 increases total 25(OH)D concentration more than vitamin D2, while vitamin D2 supplementation leads to a decrease in 25(OH)D3, explaining the different effect on total 25(OH)D.
RCT
Rigorous JournalHighly CitedDifferential Effects of Oral Boluses of Vitamin D2 vs Vitamin D3 on Vitamin D Metabolism: A Randomized Controlled Trial
Oral bolus vitamin D2 is less effective than vitamin D3 in elevating total serum 25(OH)D concentration, and may have different effects on vitamin D metabolism.
RCTRigorous JournalVitamin D2 vs. vitamin D3: They are not one and the same
Vitamin D3 is more than twice as effective as vitamin D2 at raising vitamin D levels, when given at a low dose in a physiologically relevant and public health-friendly manner.
Meta-AnalysisVitamin D2 vs. vitamin D3: Are they one and the same?
Vitamin D2 and D3 may have distinct and significant differences in efficacy, potentially impacting vitamin D status and calcium absorption.
Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2.
Vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than vitamin D2, challenging the assumption that they have equal nutritional value in humans.
Non-RCTHighly CitedUrinary metabolic profiles after vitamin D2 versus vitamin D3 supplementation in prediabetes
Vitamin D2 and D3 supplementation do not result in different urinary metabolite profiles, supporting no biological difference between the two vitamins in prediabetes patients.
RCTRigorous JournalLong-term vitamin D3 supplementation is more effective than vitamin D2 in maintaining serum 25-hydroxyvitamin D status over the winter months
Daily vitamin D3 supplementation is more effective than vitamin D2 in maintaining serum 25-hydroxyvitamin D status over winter months in healthy adults.
RCTVery Rigorous JournalHighly CitedVitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D.
Vitamin D2 is as effective as vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and does not negatively influence D3 levels.
RCTRigorous JournalHighly Cited