Sleep · Stress · Immunity
Peptide Ways crosses into the stress response
Blood assays were a peculiar destination for my sleep questions. DSIP and Selank have some interesting ways out of their usual categories.
ACTH fell. Cortisol carried on.
In a 1989 experiment, men received intravenous DSIP, a peptide named for sleep. The researchers found a significant reduction in the blood's ACTH-like immunoreactivity for at least three hours. Cortisol was unaffected and followed its normal daily decline. That split is where Peptide Ways begins.
ACTH is the pituitary hormone that stimulates cortisol production. An antibody assay detects material that reacts like ACTH; the paper calls that signal ACTH-like immunoreactivity. I prefer the authors' precise wording to the tempting shorthand that DSIP simply lowers stress. The experiment measured a particular blood signal, and the neighboring hormone measurement went its own way.
A molecule associated with sleep had crossed into a hormone experiment. My curiosity runs across the assays: how far do its effects extend, and which observations actually travel together?
Selank's immune ancestry
Selank makes the crossing from the other direction. It is a synthetic extension of tuftsin, an immune peptide, yet much of its research concerns anxiety. A study in patients with anxiety-asthenic disorders examined immune signals as well: Selank altered the Th1/Th2 cytokine balance and modulated IL-6 expression in peripheral blood. Cytokines are signals used by immune cells.
I had expected Selank's immune ancestry to be an introductory curiosity. It becomes much harder to dismiss when a human paper returns to immune measurements. It also complicates the safety question: the consequences in people with autoimmune conditions, infection or immune-modulating medication remain uncharacterized.
The Selank research compound page starts with the added tail and follows that immune connection into the anxiety experiments.
Sleep experiments
The sleep question still matters. An early DSIP pilot in six middle-aged chronic insomniacs reported longer sleep, fewer interruptions, slightly more REM and no daytime sedation. The later critical review of DSIP found the sleep hypothesis weakly documented and the underlying biology unresolved. That uneven history leaves me unconvinced of a reliable sleep treatment.
Selank's sleep reputation is more indirect. Community accounts sometimes connect quieter anxiety with easier sleep; those are anecdotal accounts, not clinical evidence. Its molecular pharmacology review concerns anxiety-related mechanisms, rather than establishing a sleep benefit.
The comparison puts the actual measurements alongside one another. For questions about approval, interactions and community reports, there is a separate FAQ. Neither compound has FDA or EMA approval; compounded prescription forms also have no FDA approval.