Vitamin D2 is still often prescribed, even though a decade of studies have found it to be inferior to D3

Created September 2025

Perplexity AI

Prescription Vitamin D Market Share: D2 vs D3

While vitamin D3 (cholecalciferol) has gained significant market dominance in the supplement market, vitamin D2 (ergocalciferol) still maintains a substantial presence in prescription vitamin D , particularly for high-dose therapeutic uses.

Current Prescription Patterns

Prescription vitamin D2 remains commonly prescribed despite D3's superior efficacy. Key findings include:

Ergocalciferol prescriptions reached 15.9 million in the United States in 2022 clincalc
The standard 50,000 IU prescription formulation is only available as vitamin D2 in the United States consultant360+1
Many physicians continue prescribing D2 for vitamin D deficiency treatment, particularly using the established protocol of 50,000 IU weekly for 6-8 weeks pmc.ncbi.nlm.nih+2

Market Trends and Professional Preferences

The prescription landscape shows mixed patterns:

D2 Prescription Advantages:

Standardized high-dose formulation : The 50,000 IU capsule is only available as D2 by prescription goodrx+1
Cost considerations : Ergocalciferol is often available as a lower-cost generic option drugs+1
Established protocols : Many clinical guidelines still reference D2 dosing regimens jamanetwork+1
D3 Growing Preference:
Superior efficacy : Research consistently shows D3 raises 25(OH)D levels more effectively than D2 pubmed.ncbi.nlm.nih+2
Professional recommendations : Many healthcare providers now prefer D3 when available singlecare+1
Better bioavailability : D3 demonstrates superior absorption and longer duration of action academic.oup+1

Geographic and Specialty Variations

Prescribing patterns vary by:

Specialty practice : Endocrinologists and bone specialists may have different preferences than primary care physicians
Regional variations : Some studies show 82.9% of clinicians prescribed vitamin D before COVID-19 , with general practitioners more likely to prescribe than specialists pmc.ncbi.nlm.nih
Institution-specific protocols : Many healthcare systems maintain established D2 protocols pmc.ncbi.nlm.nih

Clinical Evidence Impact

Recent meta-analyses have influenced prescribing:

A 2024 comprehensive review of 20 studies found D3 consistently superior to D2 in raising vitamin D levels pubmed.ncbi.nlm.nih
The difference was 40% higher effectiveness for D3 in daily dosing studies pubmed.ncbi.nlm.nih
However, this advantage disappears in patients with BMI >25 kg/m² drugs

Current Recommendations

Professional societies now generally recommend:

D3 preferred when available for supplementation and treatment clevelandclinic+1
D2 acceptable alternative , particularly for high-dose prescription therapy aafp
Either form effective for correcting deficiency when properly dosed ods.nih

While I cannot provide an exact current percentage of D2 vs D3 prescriptions, the evidence suggests that prescription vitamin D2 maintains significant market share, particularly for high-dose therapeutic protocols , even as D3 gains preference among healthcare providers who have flexibility in their prescribing choices. The persistence of D2 in prescriptions is largely due to the availability of the standard 50,000 IU formulation exclusively as ergocalciferol and established clinical protocols that continue to reference D2 dosing regimens.

References

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Tags: Vitamin D2