Using an approved drug for a purpose not listed in its official FDA approval — legal when prescribed by a physician, but not evidence of efficacy for the off-label use.Off-label prescribing is common and sometimes evidence-based, sometimes not. Key distinctions: (1) Off-label use of an approved drug is not the same as community use of a research peptide with no approval at all. (2) FDA approval for indication X does not establish efficacy for indication Y, even if the mechanism seems related. (3) The compound being off-patent and widely prescribed off-label does not mean Phase III evidence exists for the off-label indication. These distinctions are frequently blurred in community discourse.