Peptides that are either approved medicines or in late-stage clinical trials, the GLP-1s (semaglutide, tirzepatide) for weight and diabetes, insulin, PT-141 for sexual desire, oxytocin, and a handful of approved immune and metabolic agents. This is the only cluster where you can talk about effects with reasonable certainty. Even here, evidence is for specific approved indications. Off-label use is still off-label.
Cluster assignment reflects each peptide’s primary intent, its main reason for being on the site. Some peptides span clusters in practice (tesamorelin is approved for HIV-associated visceral fat but is also chased by bodybuilders); we file each under one canonical cluster and link out where the cross-over matters.