This question reminded me of something else I've always wondered about. We know about the US' troubling history of unethical scientific research -- but what about their counterparts in the USSR? With state censorship of the press being the norm back then, is there any way to know what sorts of things they got up to?
And before anyone asks, no, the Russian Sleep Experiment doesn't count.
Communists regularly burned their records for a reason, so we will hardly ever know the truth. As for the experiments performed on the inmates of Stalin’s labour camps you should see info on Butugychag camp and uranium mines. It is claimed that large medical facility located there was exploring effects of radiation on human brain and left a legacy of thousands of unburied surgically opened human skulls still scattered in the permafrost.