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Vitamin D2

Vitamin D2 suppliers and sourcing guide

Vitamin D2 (ergocalciferol) is made by exposing ergosterol, a sterol isolated from yeast and other fungi, to ultraviolet light and then purifying the product by crystallization. It contains no animal-derived starting material. Like vitamin D3 it is extremely potent and sensitive to light, air and heat, so brands mostly buy it diluted in oil or as a stabilized powder or beadlet; UV-treated mushroom powder and vitamin D2 yeast are separate ingredients with their own regulations.

See suppliersWhat to ask for on the COA
Also known as
Ergocalciferol · Calciferol · Vitamin D2 resin · CAS 50-14-6
Facts checked
November 2026

Forms and grades of vitamin D2

Suppliers sell different products under the same name. Specify the one you need.

  • Crystalline ergocalciferol

    Pure D2 crystals used by premixers and manufacturers who dilute it themselves; handled under controlled conditions because of its potency.

  • D2 in oil

    Ergocalciferol dissolved in a vegetable or MCT oil at a stated IU/g, for softgels and liquid drops.

  • Spray-dried powder or beadlet

    D2 in a protective matrix with stabilizers at a stated IU/g, for tablets, capsules and dry blends.

  • Cold-water-dispersible (CWS) powder

    Powder made to disperse in water, used in plant-based milk alternatives, beverages and drink mixes.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Assay (HPLC)
Vitamin D2 potency in IU/g by HPLC; the basis for label claims and formula overages.
Identity
HPLC retention time and UV spectrum against an ergocalciferol reference standard.
Related substances
Pre-vitamin D2, tachysterol, lumisterol and residual ergosterol, reported for crystalline and resin forms.
Peroxide value (oil forms)
Oxidation of the carrier oil, which also signals storage conditions that degrade the vitamin.
Loss on drying and particle size (powders)
Moisture and sieve analysis for beadlets and spray-dried powders, which affect flow and blend uniformity.
Heavy metals and microbiology
Lead, arsenic, cadmium and mercury by ICP-MS, plus total plate count, yeast and mold and pathogens for food and supplement grades.

Storage, lots and expiry

Storage and shelf life

Vitamin D2 breaks down with light, heat and oxygen, so it is supplied in nitrogen-flushed, light-proof containers. Store unopened containers cool and dry, and use opened packs quickly or re-flush them with nitrogen. Suppliers state a shelf life or retest date for each lot, with HPLC assay as the retest check.

Lots and expiry dates

Potency (IU/g) is lot-specific, so calculate formula inputs from each lot's assay and include an overage for losses through the product's shelf life. Keep D2 and D3 as clearly separate inventory items, since they are not interchangeable on a label.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Vitamin D2 suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking vitamin D2 suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

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Frequently asked questions

What forms of vitamin D2 can brands buy?

Common forms include crystalline ergocalciferol, d2 in oil, spray-dried powder or beadlet and cold-water-dispersible (CWS) powder. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for vitamin D2 include?

Expect assay (HPLC), identity, related substances, peroxide value (oil forms), loss on drying and particle size (powders) and heavy metals and microbiology, each with its method, specification and result for that lot.

How should vitamin D2 be stored?

Vitamin D2 breaks down with light, heat and oxygen, so it is supplied in nitrogen-flushed, light-proof containers. Store unopened containers cool and dry, and use opened packs quickly or re-flush them with nitrogen. Suppliers state a shelf life or retest date for each lot, with HPLC assay as the retest check.

What is the regulatory status of vitamin D2?

21 CFR 172.379 permits vitamin D2 as a nutrient supplement in specified foods, such as plant-based beverages intended as milk alternatives, up to set maximum levels. 21 CFR 184.1950 describes crystalline vitamin D2 as produced by ultraviolet irradiation of ergosterol isolated from yeast and related fungi and purified by crystallization. Health Canada's Multi-Vitamin/Mineral Supplements monograph lists ergocalciferol as a source ingredient for vitamin D2.

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