This document summarizes a lecture about the biological science of BDSM. It discusses the different climates present in BDSM like fear, pain, and humiliation. It then explains how neurochemicals like dopamine, prolactin, cortisol, and oxytocin influence these climates and BDSM experiences. There is also a discussion of the endorphin levels theory, which proposes a correlation between endorphin levels and dominant/submissive reactions during a scene. The importance of aftercare is noted for resolving neurochemical experiences at an emotional and physical level.