Naked Blood: Megyaku

A young scientist named Eiji (Sadao Abe) decides to follow in his father's footsteps to help humanity by developing a drug that converts pain into pleasure. To test it out, he secretly adds his drug to a contraceptive that his mother has been performing clinical trials on with three young women at a local clinic. Of these women, one is enamored with eating, one is obsessively narcissistic, while the third has one serious case of insomnia.
Eiji begins following the three unsuspecting guinea pigs to see their reaction to his new creation, covertly videotaping them and methodically recording the results. Things start to get out of control when the women realize that the more pain they inflict on themselves, the better it feels! Eiji is unable to contain the womens' obsession with pleasure and his own obsession with one of them. (official distributor synopsis)