Selank vs DSIP: the quick answer
Selank and DSIP show up in the same vendor listings, filed under stress, sleep, and recovery. The overlap mostly ends there. Selank is a Russian anxiolytic with a registered pharmaceutical status and multiple proposed mechanisms of action. DSIP is a Swiss-discovered peptide studied for sleep and growth hormone effects, with no identified receptor, gene, or precursor protein despite research dating to 1977.
| Feature | Selank | DSIP |
|---|---|---|
| Origin | Synthetic heptapeptide extended from tuftsin, Russian Academy of Sciences, Moscow | Synthetic nonapeptide isolated from rabbit cerebral blood, Basel, Switzerland, 1977 |
| Sequence / molecular weight | Thr-Lys-Pro-Arg-Pro-Gly-Pro, 751.9 Da | Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, 848.81 Da |
| Primary research focus | Anxiolytic behavior, via enkephalinase inhibition and GABAergic modulation | Sleep induction, growth hormone release, and HPA axis activity |
| Receptor / mechanism status | Multiple documented pathways: enkephalinase inhibition (IC50 15 microM), GABA-A modulation, BDNF effects | No receptor, gene, or precursor protein identified after nearly 50 years of research |
| Regulatory status | Registered pharmaceutical in Russia, sold as an anxiolytic nasal spray | Never approved anywhere; no active Phase 2 or Phase 3 trials on ClinicalTrials.gov |
| Strongest human evidence | Observational Russian registration data; no published RCT against validated anxiety scales | Double-blind insomnia trial, n=16, weak effect flagged by its own authors |
Where each compound comes from
Selank was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, working with the V.V. Zakusov Research Institute of Pharmacology in Moscow. Researchers extended tuftsin, a four-amino-acid immune-system fragment, with a Pro-Gly-Pro tail to slow its breakdown in plasma. The resulting heptapeptide gained pharmaceutical registration in Russia as an anxiolytic nasal spray. It has no approved status in the EU, the US, or Indonesia, and outside Russia it remains a research compound.
DSIP has a different lineage. A Basel research group led by Schoenenberger and Monnier isolated it in 1977 from the cerebral venous blood of rabbits after electrically stimulating the thalamus in a pattern known to produce delta-wave EEG activity, the signature of slow-wave sleep. The name reflects that early EEG association, not a confirmed sleep mechanism. A 2006 review in the Journal of Neurochemistry called DSIP "a still unresolved riddle," and no subsequent published research has closed that gap (Kovalzon and Strekalova, J Neurochem, 2006, PMID 16539679).
Mechanism: a defined pathway versus an unidentified receptor
Selank's anxiolytic effect has three separately documented routes in the literature. Zozulya and colleagues showed that Selank inhibits the enzymatic breakdown of plasma enkephalins with an IC50 of 15 micromolar, and that patients with generalized anxiety disorder had shorter enkephalin half-lives and lower enkephalinase activity than controls (Zozulya et al., Bulletin of Experimental Biology and Medicine, 2001, PMID 11550013). Separate work on rat brain gene expression points to modulation of GABAergic neurotransmission, the same general system benzodiazepines act on, and a third line of research documents Selank's effect on brain-derived neurotrophic factor after chronic ethanol exposure in rats. Three routes are not proof of a unified mechanism, but each has its own supporting data set.
DSIP's best-supported mechanism sits in growth hormone regulation, not sleep. Iyer and McCann injected DSIP into the third cerebral ventricle of rats and measured a significant rise in plasma growth hormone by 30 minutes, with a minimal effective dose of 0.1 micrograms. Pretreatment with pimozide, a dopamine receptor blocker, eliminated the effect, and dispersed pituitary cells released more growth hormone when exposed to DSIP directly, with the response peaking near 50 percent above baseline at a concentration of 10-10 M (Iyer and McCann, Peptides, 1987, PMID 3575154). That pathway is clear and reproducible. It says nothing about how DSIP might promote sleep, since the receptor responsible for any sleep effect, if one exists, has never been found.
What the evidence shows: anxiety versus sleep
The Selank literature is almost entirely animal-based, but internally consistent. Konstantinopolsky, Chernyakova, and Kolik gave Selank at 0.3 mg/kg to rats in a naloxone-precipitated morphine withdrawal model and found a 39.6 percent reduction in the total withdrawal index, with tactile sensitivity thresholds rising ninefold versus controls. Diazepam at 2 mg/kg produced a somewhat larger reduction, but at more than six times the Selank dose (Konstantinopolsky et al., Bulletin of Experimental Biology and Medicine, 2022, PMID 36322304). Human data for Selank comes from Russian pharmaceutical registration records rather than a peer-reviewed randomized trial; no published study has tested it against validated scales such as the Hamilton Anxiety Rating Scale or the GAD-7.
DSIP has the opposite problem: genuine double-blind human trials, but results that disagree with each other. Bes and colleagues ran a double-blind, matched-pairs trial in 16 chronic insomnia patients and found higher sleep efficiency and shorter sleep latency with intravenous DSIP at 25 nmol/kg versus placebo, though the authors flagged the effect as weak and possibly confounded by a shift in the placebo group's own sleep during the study (Bes et al., Neuropsychobiology, 1992, PMID 1299794). On the endocrine side, Bjartell and colleagues found that intravenous DSIP reduced plasma ACTH for at least three hours in 11 healthy men, in a double-blind crossover design (Bjartell et al., Psychoneuroendocrinology, 1989, PMID 2554357), while a later double-blind study using a stronger HPA-axis stimulus found no such effect. Two double-blind trials, two different questions, two different answers. DSIP's core sleep and stress claims stay open rather than settled.
Storage and handling in research protocols
Both peptides ship lyophilized and follow the general handling rules used across the catalog: freezer storage before reconstitution, refrigeration afterward, and use within the stated window once a vial is opened. Selank is stable for at least 24 months at -20 degrees C before reconstitution and should be used within 28 days once dissolved in bacteriostatic water and kept at 2-8 degrees C, a process covered step by step in the reconstitution guide. DSIP degrades faster once it is in solution. Graf, Saegesser, and Schoenenberger measured rapid cleavage of the peptide's N-terminal tryptophan in human and rat blood, with reported plasma half-life estimates of 7 to 15 minutes, so a reconstituted DSIP solution needs tighter cold-chain discipline than the Selank protocol requires.
Work out exact reconstitution volumes with the dosing calculator before opening a vial. Reopening a multi-dose vial repeatedly to redo the math raises contamination risk for both compounds.
Sourcing notes for researchers in Indonesia
Ambient temperatures across Bali, Jakarta, and Surabaya run 28 to 33 degrees C year-round, with humidity that regularly exceeds 70 percent. That combination degrades any lyophilized peptide left outside a sealed, desiccated container, and it is harder on a fast-clearing compound like DSIP once reconstituted than on Selank. Neither peptide holds BPOM clearance for human therapeutic use in Indonesia; both remain research-use materials here as they are everywhere outside Russia. The lyophilized peptide storage guide covers refrigeration setups suited to tropical ambient conditions in more depth.
Full compound profiles for both peptides are available in the Selank research overview and the DSIP research overview. Both are listed alongside Semax in the compounds catalog, the third peptide commonly grouped with Selank and DSIP in vendor listings despite acting through yet another distinct pathway.