What does viosterol mean?
Viosterol is the chemical name for ergocalciferol, commonly called vitamin D2. It is one of the two principal forms of vitamin D, the other being cholecalciferol, or vitamin D3. Vitamin D2 can be produced from plant or fungal sterols and is used in supplements, fortified foods, and preparations prescribed for vitamin D deficiency. Although vitamin D3 is often preferred in supplements, viosterol remains an important option and is particularly useful in contexts involving dietary restriction or medically supervised replacement therapy. The term appears in older medical literature as well as on current ingredient labels, where it may appear alongside ergocalciferol or vitamin D2. Viosterol is therefore both a precise chemical designation and a practical synonym that connects older medical usage with modern nutritional terminology.
nounViosterol is ergocalciferol, the chemical form of vitamin D2. It is used in dietary supplements, food fortification, and the treatment or prevention of vitamin D deficiency.
- The chemical form of vitamin D known as vitamin D2 or ergocalciferol, especially as a supplement or fortificant.
"The pharmacist explained that viosterol was the vitamin D2 form listed on the supplement label."
"The clinician prescribed viosterol to address the patient's confirmed vitamin D deficiency."
"The product label lists viosterol, also known as vitamin D2, among its active ingredients."
The plural is uncommon because viosterol is normally treated as a mass noun; it generally refers to distinct formulations or samples.
"The laboratory compared several viosterols prepared from different sources."
Viosterol is vitamin D2—the form associated with plant and fungal sterols—while the vitamin D found in many animal-derived supplements is D3.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of viosterol
Viosterol is an early twentieth-century name that emerged during the identification and naming of vitamins, especially vitamin D. Its formation incorporates -sterol, a chemical suffix derived from Greek stereos, meaning “solid.” The name became established for vitamin D2, now more commonly called ergocalciferol; ergosterol and sitosterol are related names within the sterol family, and ergosterol is also the precursor used to produce vitamin D2.
How viosterol is actually used
Viosterol is a technical or historical name and is usually treated as a mass noun. In contemporary medical and nutritional labeling, ergocalciferol and vitamin D2 are often more familiar terms.
Easily confused with viosterol
Viosterol is vitamin D2, whereas cholecalciferol is vitamin D3.