SYS ONLINE
SUPPLEMENT_SCHOLAR
evidence · mechanism · dose
Supplements/Vitamin

Vitamin D2 (Ergocalciferol)

Plant-derived prescription D — high doses (50,000 IU) used for rapid deficiency correction.

Buy
Quick picks · code supplementsch-20 auto-appliedSee all →
Third-party testedThird-party testedAmazon →CapsulesCapsulesAmazon →PowderPowderAmazon →Best sellersBest sellersAmazon →
Bone HealthGeneral Wellness

Overview

Plant-derived prescription D — high doses (50,000 IU) used for rapid deficiency correction.

Natural sources
  • Whole-food sources (animal products for fat-soluble and B-complex vitamins; produce for water-soluble vitamins)
  • Fortified foods (cereals, dairy, plant milks, nutritional yeast)
  • Multivitamins or stand-alone supplements in synthetic or food-derived form
Common forms
  • Capsule or softgel
  • Sublingual tablet or liquid
  • Methylated active form for sensitive individuals
  • Multivitamin matrix

Forms & variants of Vitamin D2 (Ergocalciferol)

Different chemical forms of Vitamin D2 (Ergocalciferol) behave differently. Browse each form's mechanism, bioavailability, and best-use context.

D3 (Cholecalciferol)
Vitamin D3 (Cholecalciferol)

Preferred form for raising 25(OH)D — the active form your skin makes from sun.

Mechanism of action

Same VDR endpoint as D3, but ~30% less effective at raising 25(OH)D per unit.

Pathways
  • · Same VDR endpoint as D3, but ~30% less effective at raising 25(OH)D per unit

Effects on the body

Supports
Corrects deficiency at high prescription dose

Organ system effects

Bones

Vitamin D2 (Ergocalciferol) contributes to bone mineralization, osteoblast activity, or calcium-phosphate homeostasis.

Evidence-based benefits

Corrects deficiency at high prescription dose

Strong evidence

Potential side effects

Common
    Rare
      Serious
      • · Hypercalcemia (acute high-dose)

      Drug interactions

      Prescription medications (general)
      Always disclose Vitamin D2 (Ergocalciferol) use to your prescriber — additive, antagonistic, or pharmacokinetic interactions are possible.
      minor

      Supplement interactions

      Pairs well with
      • A high-quality multivitamin
        Covers micronutrient cofactors that support most supplement pathways.
      • Omega-3 (EPA/DHA)
        Foundational anti-inflammatory support that complements most regimens.
      Avoid combining with

      No specific avoidances listed.

      Dosing & bioavailability

      Typical dose
      50,000 IU weekly × 8 wk (Rx)
      Best form
      Most evidence is based on the capsule or softgel form.
      Timing
      Consistent daily timing recommended; split larger doses if GI tolerance is a concern.
      With food?
      With fat

      Where to buy

      Affiliate links — we may earn a commission at no extra cost to you. Amazon code supplementsch-20 is auto-applied at checkout. We don't endorse specific brands; verify third-party testing (USP, NSF, Informed Sport) before purchase.

      Buy on AmazonCode supplementsch-20 auto-applied
      Scientific evidence8Show studies
      Meta-analysisAm J Clin Nutr · 2012

      Vitamin D3 vs D2 in raising 25(OH)D

      Tripkovic L, et al.

      Meta-analysis comparing forms.

      Key findings

      D2 raises 25(OH)D less than D3 at equivalent doses.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — Corrects deficiency at high prescription dose

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) Corrects deficiency at high prescription dose" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "Corrects deficiency at high prescription dose". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — randomized controlled trial

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) randomized controlled trial" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "randomized controlled trial". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — meta-analysis

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) meta-analysis" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "meta-analysis". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — pharmacokinetics

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) pharmacokinetics" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "pharmacokinetics". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — safety adverse events

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) safety adverse events" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "safety adverse events". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewPubMed (NLM) · 1970

      PubMed: Vitamin D2 (Ergocalciferol) — dose response

      Live PubMed search

      Live results for "Vitamin D2 (Ergocalciferol) dose response" across the PubMed/MEDLINE peer-reviewed index.

      Key findings

      Opens current human and preclinical literature matching Vitamin D2 (Ergocalciferol) and "dose response". Filter by RCT, meta-analysis, or year on the results page.

      Open study
      Systematic reviewGoogle Scholar · 1970

      Google Scholar: Vitamin D2 (Ergocalciferol) — clinical evidence

      Live Scholar search

      Cross-database citation index for Vitamin D2 (Ergocalciferol) as it relates to "clinical evidence".

      Key findings

      Includes preprints, theses, and journal articles. Useful for tracking citation counts and follow-on work.

      Open study
      Educational use only. This profile is not medical advice. Consult a qualified healthcare professional before starting any supplement, especially if you take prescription medication or have a chronic condition.

      Community discussion

      (0 threads)

      Share your experience or read what others have tried. Anecdotes are not medical advice.

      Sign in or create a free account to post or reply.
      Loading discussion…