Vitamin D3

Most origin questions on this site require a detour into manufacturing, because the regulation defines a substance and leaves the source open. Vitamin D is the exception: the definition contains the answer, and the answer is the digit.

What the regulation says

Vitamin D2, also called ergocalciferol, “is produced by ultraviolet irradiation of ergosterol isolated from yeast and related fungi and is purified by crystallization.”

Vitamin D3, also called cholecalciferol, “occurs in, and is isolated from, fish liver oils. It is also manufactured by ultraviolet irradiation of 7-dehydrocholesterol produced from cholesterol.”

Yeast and fungi on one side. Fish liver oil or cholesterol on the other. That is unusually direct, and it means the number after the D is doing work that the ingredient name usually refuses to do.

What follows, and what does not

D3 is animal-derived unless a manufacturer says otherwise. The regulation names fish liver oil and cholesterol, and cholesterol is an animal substance. A supplement listing plain cholecalciferol has not told you it came from anywhere else.

Vegan D3 exists and is a claim, not a default. Some D3 is produced from lichen, and manufacturers who do that say so on the label, in the same way “vegetable glycerin” is a claim someone is accountable for. Its absence is not evidence either way, which is the standing rule on the page for people avoiding animal ingredients.

D2 is the fungal one, so a reader avoiding animal ingredients who finds D2 on a label has a clean answer without needing a certification.

We are not going to tell you the two forms are interchangeable in the body, because that is a clinical question with a real literature behind it and it is not ours to settle. What is ours is where each one comes from.

The capsule, which is a second question

A vitamin D supplement has two animal-origin questions and the second one catches people.

The vitamin is one. The shell is another, and a softgel capsule is very often Gelatin, which is made from pig or cow collagen. So a lichen-derived D3 inside a gelatin softgel is not a vegan product, and the ingredient list shows both if you read past the active.

The plant answer to that is a hypromellose capsule, and manufacturers who use it advertise it, because it is the whole reason someone would choose their product.

For halal and kosher readers

The fish liver oil route raises the questions fish always raises, and the cholesterol route raises the origin question this site keeps meeting. Neither is answered by the ingredient list, and both are answered by a certification mark, which is the pattern the halal and kosher page sets out. As always, what an ingredient is derived from is ours to describe, and what follows from that is your authority’s.