DSIP has a plasma half-life of approximately 15-30 minutes, but its physiological effects persist for 6-8 hours due to downstream modulation of stress hormones and GABA systems. Single evening administration is sufficient for sleep benefits, with effects manifesting within 30-60 minutes post-injection. The short half-life explains why DSIP doesn't cause prolonged sedation or next-day grogginess despite its sleep-promoting effects.
PubMed: DSIP pharmacokinetics