Editorial note: this article summarises published research on cognitive peptides. Baclabs does not sell these compounds or any peptide; we supply bacteriostatic water and reconstitution consumables. Nothing here is medical advice.
The term cognitive peptides covers a loose group of short amino-acid chains marketed for memory, mood, focus and sleep. It brings together compounds with very different pedigrees: a couple are registered medicines in Russia with decades of human use, several have only animal or cell-culture data, and at least one is a vendor coinage with no peer-reviewed literature at all. Lumping them together as “nootropic peptides” hides those differences, and the differences are the whole point.
This pillar maps the landscape as the evidence stands. It explains what each compound is, what mechanism is proposed, what the strongest published evidence actually shows, and where the gaps are. It then points to four detailed articles: Semax versus Selank, Dihexa versus the “Adamax” analogues, the bioregulators Epithalon and Pinealon, and delta sleep-inducing peptide (DSIP). Throughout, the emphasis is on separating licensed medicines and human trial data from investigational compounds tested only in rodents or dishes.
None of these peptides holds a UK marketing authorisation. Under regulation 46 of the Human Medicines Regulations 2012, an unauthorised medicinal product may not be sold or supplied in the UK [1]. Material sold to hobbyists as “research chemicals” sits outside the licensed-medicine system entirely, with no regulated quality, dosing or safety oversight.
What counts as a cognitive peptide?
Most compounds in this cluster fall into three families by mechanism. The first are the Russian regulatory peptides, Semax and Selank, short heptapeptides derived from natural signalling molecules and registered as intranasal drugs in Russia. The second are neuro-regenerative compounds that act on growth-factor systems, chiefly Dihexa, an angiotensin IV analogue that modulates the hepatocyte growth factor (HGF)/c-Met pathway. The third are the Khavinson bioregulators, Epithalon and Pinealon, very short peptides proposed to influence gene transcription and cellular ageing. DSIP sits slightly apart as a sleep- and stress-related nonapeptide.
Grouping by mechanism matters because it predicts what the evidence looks like. The Russian peptides have human clinical publications, though mostly in Russian-language journals with small samples. The growth-factor and bioregulator compounds are dominated by preclinical work. Reading across the group without noting that distinction is how anecdote gets laundered into apparent fact.
Semax and Selank: the Russian regulatory peptides
Semax is a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) combining the ACTH(4-7) fragment of adrenocorticotropic hormone with a C-terminal Pro-Gly-Pro tripeptide that slows enzymatic breakdown. It was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences and is registered in Russia as intranasal drops. In rat hippocampus a single dose (50 µg/kg) raised brain-derived neurotrophic factor (BDNF) protein around 1.4-fold and TrkB receptor phosphorylation around 1.6-fold, with larger increases in BDNF and TrkB messenger RNA [2]. Russian clinical studies have reported benefit in acute ischaemic stroke, including work tracking plasma BDNF, motor recovery and Barthel index alongside semax administration [3][4].
Selank is a heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) based on the immunomodulatory peptide tuftsin, likewise stabilised with a Pro-Gly-Pro tail and delivered intranasally. Its proposed action is anxiolytic and GABAergic: it behaves as a positive modulator of GABA binding and inhibits enkephalin-degrading enzymes [5]. Russian comparative trials reported anxiolytic effects broadly similar to benzodiazepines such as medazepam and phenazepam, with an additional mild activating, “antiasthenic” quality and better tolerability [6][7].
Two caveats run through both. First, these are intranasal products, not injectables, the registered Russian formulations are nasal drops, and the peptides are used that way, so reconstituting them for injection is not how the clinical evidence was generated. Second, both are unlicensed in the UK. The detail is in our Semax versus Selank comparison.
Dihexa and the “Adamax” analogues: neuro-regenerative compounds
Dihexa (N-hexanoic-Tyr-Ile-(6)aminohexanoic amide) is an orally active, blood-brain-barrier-permeant analogue of angiotensin IV. Its proposed mechanism is potentiation of the HGF/c-Met system, driving dendritic branching and synapse formation [8]. The rodent data come almost entirely from one laboratory (McCoy, Benoist, Harding and colleagues at Washington State University). That provenance now carries a serious asterisk: a key 2014 paper on the HGF/c-Met mechanism was retracted in 2025 following findings of image manipulation, part of a wider research-integrity episode involving that group [9].
There are no published human trials of Dihexa itself, and its long-term safety is unknown, a particular concern given that c-Met signalling is implicated in tumour growth. The most advanced clinical relative is fosgonimeton (ATH-1017), a small-molecule HGF/MET positive modulator whose phase 2/3 LIFT-AD trial in mild-to-moderate Alzheimer’s disease (312 participants, 40 mg subcutaneously daily) missed its primary endpoint in September 2024 [10].
“Adamax” is a different matter. It is a vendor compound, not a research chemical with its own literature, described online as a Semax-derived sequence carrying an adamantane-based modification, sold under two molecular weights (984 Da and 1032 Da) that are not even the same structure. We could find no peer-reviewed studies of “Adamax” under that name. Read Dihexa versus Adamax for the full picture, including why the vendor labels matter.
Epithalon and Pinealon: the Khavinson bioregulators
Epithalon (also spelled epitalon; Ala-Glu-Asp-Gly) is a synthetic tetrapeptide developed by Vladimir Khavinson’s group in St Petersburg as a defined analogue of epithalamin, a pineal-gland extract. Its headline claim is telomerase activation: cell-culture work reported induction of the telomerase catalytic subunit and telomere elongation in human somatic cells [11], and a 2025 study again described telomere lengthening in human cell lines (a paper that later carried a published correction) [12]. Rodent work reported reduced spontaneous tumour incidence and altered ageing biomarkers in mice given roughly 30–40 µg/kg on five consecutive days each month [13].
The much-cited human “longevity” data are from epithalamin, the pineal extract, not the pure tetrapeptide, follow-up studies from one research group reporting reduced mortality over 12–15 years in elderly patients given the extract alongside standard therapy, against a control group on standard therapy alone [14]. That evidence is weak: unblinded, decades old, from a single research lineage, and not independently replicated. A 2025 review concluded there are no randomised controlled trials and essentially no human safety or toxicity data for Epitalon [15].
Pinealon (Glu-Asp-Arg) is a related tripeptide proposed as neuroprotective and antihypoxic, with data confined to rodents and cell cultures [16]. Both compounds, and the recurring “epithalon protocol 10 days” search, are handled in our bioregulators article.
DSIP: the sleep and stress nonapeptide
Delta sleep-inducing peptide (DSIP) is a nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) isolated by the Schoenenberger–Monnier group in Basel in 1977 from rabbit cerebral venous blood during sleep-inducing thalamic stimulation [17]. Despite the name, its role as a genuine sleep factor has never been settled; a later review called it “a still unresolved riddle” and stressed its many apparently unrelated actions [18].
Small human studies in the 1980s and early 1990s reported improved sleep efficiency and reduced sleep latency in chronic insomniacs at intravenous doses around 25–30 nmol/kg, but the results are mixed and the trials were small and old [19]. No modern controlled data exist, and DSIP is not a licensed medicine. See our DSIP article for the trial-by-trial detail and the reconstitution maths.
Reconstitution and diluent choice
Compounds sold as lyophilised powder must be reconstituted before any use, and the diluent choice is not trivial. For a compound intended for injection, a multi-dose vial needs a preserved diluent so it can be punctured repeatedly. Baclabs supplies UK-stocked bacteriostatic water in 30 mL vials; the reconstitution guide sets out the concentration maths.
Two wrinkles apply to this cluster. First, Semax and Selank are intranasal products; the benzyl alcohol in bacteriostatic water can irritate nasal mucosa, so preservative-free saline is often chosen for nasal preparation instead, the trade-off between the two is covered in bacteriostatic versus sterile water. Second, once a bacteriostatic vial is punctured it is generally treated as usable for up to 28 days if stored correctly; see storage and shelf life.
Worked examples: Epithalon 10 mg and DSIP 5 mg
The formula is the same for every lyophilised vial: concentration = milligrams in the vial ÷ millilitres of diluent. A U-100 insulin syringe holds 100 units per millilitre, so each unit is 0.01 mL and carries the concentration divided by 100. The two vial sizes most often seen in this cluster are 10 mg Epithalon and 5 mg DSIP; the table shows what 1, 2 and 3 mL of diluent produce for each.
| Vial | Diluent added | Concentration | Per unit (U-100) | Units for 1 mg | Units for 100 mcg |
|---|---|---|---|---|---|
| Epithalon 10 mg | 1 mL | 10 mg/mL (10,000 mcg/mL) | 100 mcg | 10 | 1 |
| Epithalon 10 mg | 2 mL | 5 mg/mL (5,000 mcg/mL) | 50 mcg | 20 | 2 |
| Epithalon 10 mg | 3 mL | 3.33 mg/mL (3,333 mcg/mL) | 33.3 mcg | 30 | 3 |
| DSIP 5 mg | 1 mL | 5 mg/mL (5,000 mcg/mL) | 50 mcg | 20 | 2 |
| DSIP 5 mg | 2 mL | 2.5 mg/mL (2,500 mcg/mL) | 25 mcg | 40 | 4 |
| DSIP 5 mg | 3 mL | 1.67 mg/mL (1,667 mcg/mL) | 16.7 mcg | 60 | 6 |
Worked example: 10 mg Epithalon + 2 mL bacteriostatic water = 5 mg/mL = 5,000 mcg/mL; each unit on a U-100 syringe holds 50 mcg, so 20 units contain 1 mg. For DSIP, 5 mg + 2 mL = 2.5 mg/mL = 2,500 mcg/mL, or 25 mcg per unit. The 3 mL rows give awkward decimals, which is why 1 mL and 2 mL are the usual choices; the arithmetic still works, it is simply harder to read off a syringe. Whatever volume is chosen, the concentration should be written on the vial with the date of first puncture. These quantities illustrate the maths only: as the sections above explain, no human dose has been established for either compound.
How to read the evidence across this cluster
| Compound | Origin and proposed mechanism | Strongest human evidence | Licensed anywhere? |
|---|---|---|---|
| Semax | ACTH(4-7)-Pro-Gly-Pro; BDNF/TrkB upregulation [2] | Russian stroke studies, small samples [3][4] | Russia (intranasal) |
| Selank | Tuftsin analogue; GABA modulation, enkephalinase inhibition [5] | Russian anxiety trials versus benzodiazepines [6][7] | Russia (intranasal) |
| Dihexa | Angiotensin IV analogue; HGF/c-Met potentiation [8] | None; key mechanism paper retracted [9] | No |
| Epithalon | Synthetic pineal tetrapeptide; telomerase induction in vitro [11] | None for the tetrapeptide; extract follow-ups only [14][15] | No |
| Pinealon | Tripeptide; antihypoxic, neuroprotective in rodents [16] | None | No |
| DSIP | Nonapeptide from rabbit cerebral blood [17] | Small 1980s–90s insomnia trials, mixed [19] | No |
Set expectations by data type. Semax and Selank have human clinical publications, but mostly small, Russian-language and single-region. Dihexa, Epithalon and Pinealon rest on preclinical work, some of it now under a retraction cloud. DSIP has only small, dated human trials with inconsistent results. “Adamax” has none. Marketing copy tends to flatten all of this into confident promises; the underlying literature does not support that confidence, and known safety data are thin to non-existent for most of the group.
Three questions help when reading any claim about a compound in this cluster. Was the study in humans, and if so how many, with what comparator and what blinding? Was the route the same as the one being marketed, intranasal for Semax and Selank, intravenous in the DSIP trials, subcutaneous or intramuscular in the bioregulator literature? And has anyone outside the originating group reproduced the result? For most of these peptides the answer to at least one question is no, and for several it is no to all three. That does not make the compounds inert; it means the confident dosing schedules that circulate online are not derived from evidence that can be checked.
Frequently asked questions
Are cognitive peptides legal in the UK?
None holds a UK marketing authorisation. Under regulation 46 of the Human Medicines Regulations 2012, an unauthorised medicinal product cannot be sold or supplied as a medicine [1]. Compounds sold as “research chemicals” fall outside the licensed system, so quality, dosing and safety are unregulated. A prescription medicine is obtained only through a prescriber.
Which cognitive peptides have real human data?
Semax and Selank have the most, with Russian clinical studies in stroke and anxiety respectively, though samples are small [3][6]. DSIP has a handful of small, old sleep trials with mixed results [19]. Dihexa, Epithalon and Pinealon are supported mainly by animal or cell studies, and “Adamax” has no peer-reviewed literature at all.
Are Semax and Selank injected?
No. Both are registered in Russia as intranasal drops, and the clinical evidence was generated with nasal, not injectable, delivery. Vendors sometimes sell lyophilised powder for reconstitution, but injecting these peptides is not how they were studied and is not supported by the trial data.
Does Epithalon really lengthen telomeres?
Cell-culture studies from one research group report telomerase activation and telomere elongation [11][12]. That is not the same as proven anti-ageing benefit in people: the human “longevity” data come from a pineal extract, not the pure peptide, and are unblinded and unreplicated [14][15]. Treat the telomere claim as a laboratory finding, not a clinical outcome.
Is DSIP a proven sleep aid?
Not on current evidence. Small studies in chronic insomniacs reported improved sleep efficiency and shorter latency at intravenous doses around 25–30 nmol/kg, but findings are inconsistent and decades old, and one major review questioned whether DSIP is a sleep peptide at all [18][19]. There are no modern controlled trials.
References
- The Human Medicines Regulations 2012, regulation 46. legislation.gov.uk
- Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Brain Research, 2006
- The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Zh Nevrol Psikhiatr, 2018
- Effectiveness of semax in acute period of hemispheric ischemic stroke. Zh Nevrol Psikhiatr, 2001
- Peptide-based anxiolytics: the molecular aspects of heptapeptide Selank biological activity. Curr Pharm Des, 2018
- Efficacy and possible mechanisms of action of the peptide anxiolytic selank in generalized anxiety and neurasthenia. Zh Nevrol Psikhiatr, 2008
- A comparison of the anxiolytic effect and tolerability of selank and phenazepam in anxiety disorders. Zh Nevrol Psikhiatr, 2014
- Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents. J Pharmacol Exp Ther, 2013
- Retraction notice: The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the HGF/c-Met system. J Pharmacol Exp Ther, 2025
- Athira Pharma topline results, phase 2/3 LIFT-AD trial of fosgonimeton. GlobeNewswire, 2024
- Epithalon peptide induces telomerase activity and telomere elongation in human somatic cells. Bull Exp Biol Med, 2003
- Epitalon increases telomere length in human cell lines through telomerase upregulation or ALT activity. 2025
- Effect of Epitalon on biomarkers of aging, life span and spontaneous tumor incidence in female SHR mice. Biogerontology, 2003
- Peptide geroprotector from the pituitary gland inhibits rapid aging of elderly people: 15-year follow-up. Bull Exp Biol Med, 2011
- Overview of Epitalon, highly bioactive pineal tetrapeptide with promising properties. Int J Mol Sci, 2025
- Pinealon protects the rat offspring from prenatal hyperhomocysteinemia. 2012
- Characterization of a delta-electroencephalogram (sleep)-inducing peptide. PNAS, 1977
- Delta sleep-inducing peptide (DSIP): a still unresolved riddle. Amino Acids, 2006
- Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients: a double-blind study. 1992
Disclaimer: This content is for educational purposes only and does not constitute medical advice. Bacteriostatic water is supplied for reconstitution of substances intended for research and for use as directed by a healthcare professional. Peptides and medicines discussed here may be unlicensed in the UK or prescription-only; consult a qualified clinician before using any medicine. Baclabs does not sell peptides.