Drugs with the exact same chemical formula do not always work identically in the human body, as stereoisomers and structural isomers can exhibit markedly different pharmacological properties, receptor binding, and biological effects.
The claim is that drugs with the exact same chemical formula always work identically. The retrieved papers, specifically those discussing stereoisomers and optical isomers (like the comparison of isomeric nicotinic receptor agonists and dihydroquercetin stereoisomers), explicitly show that compounds with the same chemical formula can have very different biological activities, binding affinities, and pharmacological effects due to spatial arrangements. Thus, the claim is clearly refuted by scientific evidence.