stress axis & HPA modulation

DSIP's strongest human endocrine signal

DSIP's most robustly supported human effect is not sleep itself, but a short-term reduction in ACTH-like immunoreactivity. In a randomized crossover study of 11 healthy men, IV DSIP at 25 nmol/kg reduced plasma ACTH for at least 3 hours, while cortisol followed its normal diurnal decline. This selectivity -- ACTH down, cortisol unchanged -- hints at pathway-specific modulation rather than general adrenal suppression. Understanding what this finding means, and what it doesn't, matters for reading claims about DSIP as a stress-management compound.