There's an interesting book called "Who Goes First?"[1] about something that used to be much more common than it is today: self-experimentation in medicine.
[1] - https://www.amazon.com/Who-Goes-First-Lawrence-Altman/dp/052...
[1] - https://www.amazon.com/Who-Goes-First-Lawrence-Altman/dp/052...
Self experimentation remains relatively out of reach of the ethicists and so should be kept in mind for the more creative researcher types.
See also, an old story by Scott Alexander: https://archive.fo/eSbZb.