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:
- Two of the studies administered a single bolus dose of varying quantities, one using alternate routes of administration (oral or intramuscular).
- Six studies preferred daily supplementation with dosages ranging from 1,000 to 4,000 IU.
- One study compared daily to monthly supplementation, 1,600 to 50,000 respectively, while another study supplemented 50,000 IU weekly.
- The final study compared a single intramuscular injection of 300,000 IU of D2 to a single oral dose of 300,000 IU D3.
The researchers found:
- In eight of the studies, regardless of the dose, frequency, or administration, concluded that cholecalciferol (D3) produced a significantly greater increase from baseline serum 25(OH)D levels compared with ergocalciferol (D2).
- Two studies showed D2 and D3 were equally effective in raising serum 25(OH)D.
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.