Compound family

Nootropic and sleep peptides

In one sentenceCognition, anxiety, stroke and sleep. Three are Russian-registered and unreplicated; two are animal-brain extracts — one with Cochrane reviews against it, one with a single Russian trial; one has never been given to a human; one was tested in the 1980s and mostly did not work.
Compounds7
Best gradeC Cerebrolysin
Approved medicines1 of 7
Prohibited in sport3 of 7

What this family is

Semax and Selank come from the same Moscow institute: Semax is a fragment of ACTH, Selank an analogue of the immune peptide tuftsin, both stabilised with the same Pro-Gly-Pro tail and given as nasal sprays. Both are registered medicines in Russia — for stroke and cognition, and for anxiety respectively. Noopept is a dipeptide-derived ester from the same Russian pharmacology tradition, registered there for cognitive impairment after injury or stroke. Cerebrolysin is different in kind: a mixture of peptides extracted from pig brain, made in Austria since the 1950s and infused for stroke and dementia across Russia, China and Eastern Europe. Dihexa is a small molecule derived from angiotensin IV with a striking effect on synapse formation in rodents. DSIP is a nonapeptide isolated from rabbit brain in the 1970s and named for the sleep pattern it appeared to induce.

The Russian registrations rest on a literature that is almost entirely Russian-language, largely uncontrolled or poorly reported by international standards, and unreplicated by independent groups — which is why Semax, Selank and Noopept all sit at grade D despite being approved somewhere. Cerebrolysin is the family's exception: it has been trialled extensively, and the Cochrane reviews of those trials found no effect on death after stroke, more serious adverse events, and a dementia benefit too small and too uncertain to count on. Dihexa has no human data of any kind. DSIP is the exception in having been properly tested: several small insomnia studies through the 1980s and 90s, the best-controlled of which found effects that were weak and possibly artefactual.

None is approved in the US or UK, or EU-wide; Cerebrolysin holds national authorisations in Austria and some other countries. Dihexa and DSIP are prohibited in sport under the non-approved-substances rule.

Grade counts across the family: 0 × A · 0 × B · 3 × C · 4 × D. The best grade here, C, means weak human evidence. How LYO grades →

The compounds, graded

Every member with its best-supported outcome grade, human-trial count and regulatory status. Each opens the full evidence page.

Semax

D

Russian-developed heptapeptide, registered in Russia, unstudied elsewhere.

Human trialsRussian-language, largely uncontrolled
StatusNot approved (outside Russia)

Selank

D

Russian anxiolytic peptide, registered in Russia. Same evidence problem as Semax.

Human trialsRussian-language, small
StatusNot approved (outside Russia)

Noopept (omberacetam)

D

A Russian dipeptide-derived nootropic, registered there since 2007, with one published trial — whose abstract is not even indexed.

Human trials1 Russian comparative trial vs piracetam (2008); no independent replication
StatusNot approved (outside Russia)

Cerebrolysin

C

A pig-brain peptide mixture given by infusion for stroke and dementia in some fifty countries. Cochrane: no effect on death after stroke, more serious adverse events.

Human trials7 RCTs in stroke (n=1,773); 6 RCTs in vascular dementia (n=597); many small trials
StatusApproved in Austria, Russia, China and others; not US/UK/EU-wide

Cortexin

C

A Russian brain-extract injection for stroke and cognitive decline, like cerebrolysin. One double-blind trial of 272 patients exists — with no numbers in its abstract.

Human trials1 double-blind RCT (n=272, Russian); open trials
StatusNot approved (Russia only)

DSIP (delta sleep-inducing peptide)

C

A sleep peptide that was actually tested in insomnia in the 1980s — and mostly did not work.

Human trialsSeveral small trials, 1981–1998
StatusNot approved

Dihexa

D

A potent synaptogenic molecule in rodents, and nothing at all in humans.

Human trials0 controlled
StatusNot approved

Comparisons

Questions

Are Semax and Selank approved medicines?
In Russia, yes. Not in the EU, US or UK, and the evidence behind the Russian registrations has not been published to standards that let it be checked or replicated.
Is Dihexa safe?
Unknown. It has never been tested in a controlled human trial, so there is no safety data — not a reassuring absence of harm, but an absence of information.
Does DSIP help with sleep?
Mostly not, on the evidence that exists. A double-blind trial in chronic insomnia found weak, possibly artefactual effects and concluded it was unlikely to be of major benefit. Development stopped.
Does Cerebrolysin work?
For stroke, the Cochrane review of seven randomised trials found no effect on death and more serious adverse events. For vascular dementia, a small cognitive benefit on very low-quality evidence that the reviewers judged might be too small to matter.

Written and maintained by LYO Research — how pages are written and checked. Reviewed 23 September 2026. Grades count human evidence only. Not medical advice. Correct this page →