The short answer is that some vitamin D3 is vegan, and some is not.
The common perception of vitamin D3 is that it’s only produced by animals, but this is incorrect.
It is mostly produced by animals, but can also be created by an algae-like plant called a lichen.
Vitamin D3 from lichen is vegan. All of the best vegan vitamin D supplements, just like non-vegan vitamin D supplements, are D3.
What about the other D3?
It’s true that when D3 is added to fortified foods and most supplements (that aren’t specifically vegan), it’s derived from oil in sheep’s wool (called lanolin).
Here’s a brief description of the process from a research paper, just so you have a credible source:
It is produced commercially by extracting 7-dehydrocholesterol from wool fat, followed by UVB irradiation and purification.
You might think “what’s the harm in extracting it from sheep’s wool?”
At first it doesn’t seem so bad, but animal abuse is common practice in the wool industry.
Barbaric practices like “mulesing” are widespread procedures, where a slice of flesh is carved off sheep in order to prevent infections from forming or festering.
Bottom line: Any wool product, including lanolin-derived vitamin D3, is not vegan.
Is Vitamin D Added to Fortified Foods Vegan?
Look at the box of Cheerios (or most cereals) and look at the nutritional facts.
You’ll like see that there’s vitamin D in it.
That didn’t come from any of the ingredients, which means it was added separately to fortify the foods.
Typically, this is a combination of plant-based D2 and animal-based D3.
Technically, it contains animal products because of the added vitamin D3 (ignoring all other ingredients at this point).
So is it vegan?
Technically, no, if you’re a strict vegan.
But most vegans and organizations like PETA and the Vegan Society say to not worry about it. It’s such a small amount, and it’s added to a lot of foods which can make it extremely difficult for some people to avoid.
You’ll have to make your own call, I can’t decide for you. All I can say is that most vegans are okay with it, and it will hopefully shift more and more to plant-based vitamin D over time.