Ergocalciferol, or vitamin D2, is the plant-based form of vitamin D. Manufacturers produce it from yeast or mushrooms. It supplies a vegan-friendly alternative to the animal-derived vitamin D3. Doctors often prescribe ergocalciferol in high-dose protocols to correct low vitamin D levels quickly. It does not last as long in the body as vitamin D3 and has lower overall potency.
Vitamin D2 supports calcium absorption, bone integrity, and a healthy immune response. Once blood levels are replenished, some people switch to vitamin D3 or lower maintenance doses to hold those levels steady.
Take ergocalciferol with a meal containing fat. This aids absorption since the vitamin is fat-soluble. Dosage depends entirely on lab results and a doctor’s guidance. Overdoing it can spike blood calcium, strain the kidneys, and trigger toxicity. Be cautious with thiazide diuretics, corticosteroids, and cholestyramine. Anyone managing sarcoidosis, hyperparathyroidism, or kidney disease needs medical supervision before starting.