I've been conducting a self-experiment on the effects of various substances (all legal and easily accessible) on sleep for about four months, following a similar approach to the author. Using two different sleep trackers, I rely solely on absolute, measurable values, avoiding subjective impressions. It's fun but requires time and patience—sometimes I have to restart cycles from scratch. So far, I’ve gathered datasets for Phenibut, Theanine, Piracetam, and Baclofen. The experiment is still ongoing.