Generally speaking, peer reviewed journals will not publish research on human subjects that did not receive IRB approval.

If a study was done *without* the proper IRB approval, but the study itself was ethical and clearly *would* have passed IRB approval if it had been properly submitted, is it generally possible to get a post-facto IRB approval that is sufficient to publish in most journals, or is the work forever "tainted"? Is the fact that post-facto IRB approval is not often considered an option because it literally *isn't* allowed, or because research conducted without IRB approval almost always contains ethical infirmities that would have prevented IRB approval from the start? In other words, is the requirement to obtain IRB approval truly a "You absolutely *must* have *prior* IRB approval", or is it *really* more like "You absolutely *must* not conduct research unethically, and obtaining prior IRB approval is part of Best Practices in accomplishing this, because nearly all proposals that you or I might come up with are actually unethical and we need the wisdom of the IRB to show us the light and put us on the right path. If you forgo prior approval, you are wading in crocodile-infested waters, and you will have no one to blame but yourself, not the IRB, not your mom, not your advisor, but only you yourself, if you get your leg bitten off"?

To be clear, I'm not asking whether it is possible to "whitewash" unethical research to make it look like no one was harmed when in fact people were harmed, but about institutional procedural violations in otherwise ethical research. I am well aware that one of the primary *reasons* for seeking prior IRB approval (other than because journals expect it) is to avoid committing unethical acts, so for the purpose of this question, assume that the researchers either just get lucky or are just so competent in ethical practice that their actual research demonstrates sublime virtue (just without IRB approval).