Sleep peptides like Epithalon work by stimulating your body's own melatonin production, which provides better circadian timing and avoids the receptor desensitization that can occur with long-term melatonin supplementation. DSIP takes a different approach by reducing stress hormones that interfere with sleep onset. Both can be more effective than exogenous melatonin for people who've built tolerance to supplements or need comprehensive sleep architecture improvement.
PubMed: Endogenous vs exogenous melatonin