Vitamin D2 vs Vitamin D3
How vitamin D2 and vitamin D3 differ in potency, absorption, tolerance, and cost.
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Side by Side
| Vitamin D2 (Ergocalciferol) | Vitamin D3 (Cholecalciferol) | |
|---|---|---|
| Absorption | Moderate | High |
| How it is absorbed | Absorbed like D3 via micelles, but 25-hydroxylated less efficiently and cleared faster, so it raises total 25(OH)D less per IU than D3 (Tripkovic 2012 meta-analysis). | Fat-soluble; incorporated into mixed micelles and absorbed in the small intestine, best when taken with a meal containing fat. Hydroxylated in the liver to 25(OH)D, the circulating marker of status. |
| Typical dose | 1,000-2,000 IU daily; 50,000 IU weekly as a prescription repletion regimen | 1,000-2,000 IU (25-50 mcg) daily for maintenance |
| Common uses | prescription repletion (50,000 IU capsules), vegan supplementation | general supplementation, correcting low 25(OH)D, bone health with adequate calcium |
| Side effects | Same toxicity profile as D3 at excessive doses. | Well tolerated at maintenance doses. Chronic intake well above the 4,000 IU UL can cause hypercalcemia. |
| Cost | Low | Low |
| Also called | ergocalciferol, D2 | cholecalciferol, D3 |
| Labels in index | 96 | 4,891 |
When to Choose Vitamin D2 (Ergocalciferol)
Choose vitamin D2 when you need the prescription 50,000 IU form or a plant-derived vitamin D and lichen D3 is unavailable. Produced by UV irradiation of yeast or mushrooms. Some 25(OH)D immunoassays under-detect 25(OH)D2.
Vitamin D2 (Ergocalciferol)
Works, but less durably than D3, especially in large weekly or monthly doses. Lichen-derived D3 has removed the main reason vegans chose it.
What to look for: Daily rather than intermittent dosing if D2 is what you have. Recheck 25(OH)D with an assay that measures D2 metabolites.
Find on iHerb Affiliate linkWhen to Choose Vitamin D3 (Cholecalciferol)
Choose vitamin D3 when you want the form that raises 25(OH)D most reliably per IU. Usually made from lanolin (sheep wool). Vegan D3 is extracted from lichen and is the same molecule.
Vitamin D3 (Cholecalciferol)
The default. Raises 25(OH)D more per IU than D2 and costs very little.
What to look for: 1,000-2,000 IU (25-50 mcg) per dose for maintenance. Higher strengths only with a measured 25(OH)D and a plan to recheck. USP Verified or NSF Certified.
Find on iHerb Affiliate linkProducts on Titrate
In Titrate's index of NIH label data, 96 labels in the Vitamin D category list vitamin D2 and 4,891 list vitamin D3.
Supplement Search loads one category at a time. Choose the Vitamin D tab, then type a form such as "d3" under Must contain, or a form to avoid under Must not contain.
Related
References
NIH Office of Dietary Supplements. Vitamin D: Fact Sheet for Health Professionals.
Holick MF, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930.
Ross AC, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011;96(1):53-58.
Tripkovic L, et al. 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. 2012;95(6):1357-1364.
Manson JE, et al. Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease. N Engl J Med. 2019;380(1):33-44.
Pittas AG, et al. Vitamin D Supplementation and Prevention of Type 2 Diabetes. N Engl J Med. 2019;381(6):520-530.
LeBoff MS, et al. Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults. N Engl J Med. 2022;387(4):299-309.
Demay MB, et al. Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2024;109(8):1907-1947.