Vitamin D2

vitamin · endocrine · digestive · renal · integumentary · Oral

Vitamin D2, a vitamin. Derived from UV-irradiated fungal ergosterol. Differs from D3 by an extra C22 double bond and C24 methyl, which reduces… Oral half-life 10 d.

Derived from UV-irradiated fungal ergosterol. Differs from D3 by an extra C22 double bond and C24 methyl, which reduces affinity for vitamin-D binding protein (DBP) and shortens the t½ of its 25-hydroxy metabolite. Same downstream activation — hepatic CYP2R1 → 25(OH)D2, renal CYP27B1 → 1,25(OH)₂D2 (ercalcitriol) — and same VDR binding. Head-to-head human RCTs show D2 raises serum 25(OH)D roughly 60–70% as efficiently as equimolar D3.

Pharmacokinetics

• Oral — t½ 10.0 d · F 70% · ka 0.2 h⁻¹ · Vd 14 L

Related compounds

• Vitamin D3 — synergistic
• Magnesium — synergistic

Sources: PMID:9771862