What facts constitutes as citation-worthy

Question

If I were to state a fact that is simply a part of a field, do I need to cite a scientific article that supports this? Like, let's say I write something like this:

"... tryptamine being a monoamine protein in the body, involved in the regulation of serotonergic, dopaminergic and glutamatergic systems in the brain."

Do I need to cite this? Is there anything one can remember to guide oneself in situations where one wonders whether to cite or not?

(I'm writing a treatise, which has been defined to me at least, as a text type somewhere between an essay and a scientific article)

Answer 1

Generally speaking commonly known facts, such as things that appear in encyclopedias or even undergraduate text books don't need to be cited unless quoted.

But that doesn't mean "known" to everyone. If they are common knowledge among experts, for example, then no citation is needed.

If you quote or closely paraphrase something from a source, then you should cite that source.

But it is probably better to err on the side of over citation than under and citations can also sometimes help the reader, depending on the audience. A