I noticed that the title of my question was edited from
Is there a voltage in pin?
Can I power peripherials from the 5V pins?
IMHO this changes the meaning of the question, but I'd like to ask the community, since I'm not a native English speaker.
My question is about powering the Raspberry via a GPIO pin. The direction of current is into the Raspberry. The new question title for me means: power the Raspberry normally and power the peripherals from the GPIO pin. That would mean the current flow goes out of the Raspberry. That's not what I wanted to know. I did that multiple times already.