One of the most common questions we receive about vitamin D supplementation is whether to use D2 or D3. Generally, studies show that D3 is more potent and more efficacious, and it is also the “natural” form because it’s what your own body produces.
But let’s look at a recent meta-analysis to settle the potency debate.
Tripkovic L, Lambert H, Hart K, Smith CP, Bucca G, Penson S, Chope G, Hypponen E, Berry J, Vieth R, Lanham-New S. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr. May 2012.
Professor Tripkovic and colleagues at the University of Surrey reviewed 10 randomized controlled trials (RCTs) with a collective total of 1,016 participants ages 18-97. The studies included in the review encompassed a range of different dosages and administration methods:
The researchers found:
The authors also determined whether frequency of dosage had an effect on favoring of D2 or D3. Three out of the 4 studies which used bolus doses reported results which favored using vitamin D3 to raise serum levels most effectively. When focusing on the studies which used daily supplementation the results weren’t as strong, but a clear preference for cholecalciferol was present.
So the recommendation remains that D3 is preferable to D2 for better potency. If your doctor prescribes vitamin D from a pharmacy (usually Drisdol), ask them if you might be able to take alternative steps to ensure you receive vitamin D3 instead.