What the body does to the compound — how it’s absorbed, where it goes, how it’s broken down, and how it’s eliminated.Encompasses absorption, distribution, metabolism, and excretion (ADME). Key PK parameters: bioavailability, Tmax (time to peak plasma concentration), Cmax (peak concentration), half-life, volume of distribution, and clearance. Animal PK does not reliably predict human PK — metabolic enzymes, protein binding, and renal/hepatic clearance rates all differ between species. Human PK data is essential for dosing design; community dosing protocols based on animal PK are working with incomplete information.