Therapeutic Peptides in Aesthetic, Metabolic and Endocrine Conditions: Effects, Safety, Clinical Applications, and Future Perspectives Frontiers Pichia pastoris secreted peptides crossing the blood brain barrier and DSIP fusion peptide efficacy in PCPA induced insomnia mouse models DSIP: The Deep Sleep Peptide That's Changing How High Performers Recover LIVV Delta SleepInducing Peptide (DSIP) is a small naturally occurring peptide that was first identified in the 1970s and is associated with regulating sleep, particularly deep (delta) sleep phases. It's composed of 9