Peptides for cognition & mood.
Where subjective effects are easiest to feel, hardest to measure, and most vulnerable to expectation.
Cognitive and mood peptides present a measurement problem that other categories do not. The outcomes are things like focus, clarity, motivation and anxiety, which are inherently subjective and unusually responsive to expectation. Placebo effects in psychiatric and cognitive research are famously large, which means uncontrolled personal experience is close to worthless as evidence here, more so than anywhere else on this site.
The category has a distinct geography. Several of the best-known compounds were developed in Russia and are used clinically there, with a substantial domestic literature, while remaining unapproved and largely unstudied in Western trials. This creates a genuinely awkward evidence position: it is not correct to say these compounds are untested, and it is also not correct to treat clinical use in one regulatory system as equivalent to the multi-trial evidence package a Western approval would require.
Cerebrolysin is the instructive case. It has been through many randomized controlled trials and two Cochrane systematic reviews, which is far more scrutiny than almost any compound on this site receives. Those reviews concluded that it probably has little or no beneficial effect on the outcomes studied in stroke, and were cautious about dementia. That is what good evidence looks like when it does not favour the compound, and it is more informative than the enthusiastic absence of data elsewhere.
The purely preclinical members of this category, including several designed as neurotrophic or antidepressant candidates, have mechanisms that are genuinely interesting and no human data at all. Blood-brain barrier penetration is a recurring open question, since a compound that cannot reach the brain cannot do the thing it is designed to do regardless of how well it performs in a dish.
Subjective outcomes plus strong placebo response equals a category where personal experience should carry unusually little weight. Where real trials exist, the results have often been unimpressive.
I can feel it working, so it works.
Cognitive and mood outcomes are the most placebo-responsive endpoints in medicine. Feeling an effect does not establish a pharmacological one.
Used clinically abroad means proven.
Different regulators apply different evidence standards. Clinical use in one system is a fact worth knowing, not a substitute for trial data.
Every compound in this category.
Graded on what has actually been published, with the regulatory reality on each one.
Cerebrolysin is a peptide preparation produced by the enzymatic breakdown of purified porcine (pig) brain proteins, yielding a mixture of low-molecular-weight peptides and free amino acids.
Cortexin is a low-molecular-weight polypeptide preparation extracted from the cerebral cortex of cattle and calves.
Dihexa (N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide; also referenced as PNB-0408) is a small, orally active peptidomimetic derived from angiotensin IV (Ang IV), a C-terminal fragment of the renin-angiotensin system.
DSIP (Delta Sleep-Inducing Peptide) is a small endogenous nonapeptide with the amino acid sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE), molecular weight roughly 850 Da.
N-Acetyl-Semax-amidate is a doubly end-modified synthetic analogue of Semax, the Russian-developed heptapeptide H-Met-Glu-His-Phe-Pro-Gly-Pro-OH (an ACTH(4-7) fragment extended at the C-terminus with Pro-Gly-Pro).
P21 (also written P021) is a small synthetic peptide derivative modeled on a biologically active region of ciliary neurotrophic factor (CNTF).
PE-22-28 is a synthetic seven-residue peptide corresponding to residues 22 to 28 of spadin, itself a fragment derived from the sortilin propeptide (also called neurotensin receptor-3).
Pinealon is a synthetic ultrashort tripeptide with the sequence glutamic acid–aspartic acid–arginine (Glu-Asp-Arg, abbreviated EDR).
Selank is a synthetic heptapeptide (Thr-Lys-Pro-Arg-Pro-Gly-Pro) developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, with the laboratory designation TP-7.
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) consisting of the ACTH(4-7) fragment of adrenocorticotropic hormone joined to a C-terminal Pro-Gly-Pro tripeptide.
Tracking one of these with your provider? PepCue handles the schedule, the vial math, and the record.