The market looks confusing because there's a large gray area of "research chemicals" sold online with no prescription and no clinical oversight, and those sit in a very different category from a prescribed protocol
Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland Abstract Reactive oxygen and nitrogen species can be generated endogenously (by mitochondria, peroxisomes, and phagocytic cells) and exogenously (by pollutions, UV exposure, xenobiotic compounds, and cigarette smoke)
PMID: 8216285
Diabetes Metab Res Rev 31(3):248255 Vasu S, Moffett RC, Thorens B, Flatt PR (2014) Role of endogenous GLP-1 and GIP in beta cell compensatory responses to insulin resistance and cellular stress
Safety and population pharmacokinetic analysis of intravenous acetaminophen in neonates, infants, children, and adolescents with pain or fever
The best choice really depends on what you need