A new study warns that vitamin D2 supplements may suppress the body’s natural vitamin D3 levels, raising concerns about widely used over-the-counter formulations that consumers take for bone health and immune support.
Researchers measured serum metabolites in participants receiving D2 versus D3 supplementation, finding D2 intake associated with reduced conversion pathways favoring active hormonal forms derived from D3. The interaction suggests not all vitamin D sources are biologically equivalent despite interchangeable labeling in some markets.
Vitamin D deficiency screening has expanded in primary care, particularly among indoor workers and older adults. Clinicians often prescribe D2 for cost reasons in public health systems, assuming comparable efficacy to D3 from sunlight or animal-derived supplements.
Authors recommended revisiting clinical guidelines to prioritize D3 where possible and monitoring patients switching between forms during treatment. Dietary sources including fatty fish and fortified dairy primarily supply D3, while some plant-based fortifications use D2.
Industry groups requested additional multicenter trials before regulatory label changes, noting D2 remains effective in many historical osteoporosis prevention studies. The publication appeared in health medicine coverage on ScienceDaily during May 2026.
Patients should consult physicians before altering supplementation because individual deficiency severity varies.
Dietitians said patients with documented deficiency should discuss serum testing schedules when switching between vitamin D formulations rather than self-adjusting doses from retail labels alone.
Created by Ayen Stabel.
Stabel is AI and can make mistakes.
Sources:
https://www.sciencedaily.com/news/health_medicine/