Semax
Neuropeptides
ABOUT
Semax is a peptide investigated in small human neuroimaging and clinical studies. One small placebo-controlled imaging study in healthy volunteers reported short-term changes in a resting-state brain-network measure; this does not establish clinical benefit.
EVIDENCE OVERVIEW
Too little published work to judge either way
WHAT THIS MEANS
Insufficient evidence. Review the research and limitations before relying on this record.
IDENTITY
HALF-LIFE
HOW IT IS THOUGHT TO WORK
Semax is a synthetic heptapeptide analogue of ACTH(4-10) (Met-Glu-His-Phe-Pro-Gly-Pro) with no corticotropic activity. In rats, intranasal Semax raised hippocampal BDNF protein about 1.4-fold with a 1.6-fold rise in trkB tyrosine phosphorylation, and increased exon III BDNF and trkB mRNA 3-fold and 2-fold. Specific binding was demonstrated in rat forebrain basal nuclei with a Kd of 2.41 nanomolar.
PHARMACOKINETICS
Given intranasally. Dipeptidylaminopeptidases cleave it successively to the pentapeptide HFPGP and then the tripeptide PGP - the tripeptide metabolite is itself biologically active, which complicates attributing effects to the parent peptide. In-vitro half-life in the presence of plasma membranes exceeded one hour; no in-vivo human value is established.
REVIEW
PUBLISHED PAIR RECORDS
with na-semax-amidate
Same peptide, one chemically modified for stabilityNA Semax Amidate is Semax with an acetylated N-terminus and an amidated C-terminus - standard chemistry to resist the exopeptidases that degrade the parent. It is the same intended target with a different degradation profile, not a second mechanism, so combining them stacks one pharmacology rather than two. Peppy keeps them as separate records because evidence does not transfer between them: what clinical use exists applies to the parent, and the modified form has never been tested in a trial anywhere. The modification is not purely additive either - for Semax, the free N-terminus that acetylation removes was itself shown to be protective against copper-induced toxicity in a cell line. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026with Selank
Overlapping neuroactive claims, none independently replicatedSemax and Selank are commonly combined for cognitive or mood effects and are described as acting on overlapping neurotrophic and monoaminergic signalling rather than on separate targets. The shared problem is evidential rather than mechanistic: Semax is registered in Russia with an evidence base that is largely Russian-language and not independently replicated; Selank is registered in Russia, with one comparative anxiety report published in Russian. No study has examined this combination, and for a pair where neither component has a replicated effect, a combined effect cannot be inferred from adding two uncertain ones. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026with na-selank-amidate
Overlapping neuroactive claims, none independently replicatedSemax and NA-Selank Amidate are commonly combined for cognitive or mood effects and are described as acting on overlapping neurotrophic and monoaminergic signalling rather than on separate targets. The shared problem is evidential rather than mechanistic: Semax is registered in Russia with an evidence base that is largely Russian-language and not independently replicated; NA-Selank Amidate has no clinical trial of its own anywhere. No study has examined this combination, and for a pair where neither component has a replicated effect, a combined effect cannot be inferred from adding two uncertain ones. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026with noopept
Overlapping neuroactive claims, none independently replicatedSemax and Noopept are commonly combined for cognitive or mood effects and are described as acting on overlapping neurotrophic and monoaminergic signalling rather than on separate targets. The shared problem is evidential rather than mechanistic: Semax is registered in Russia with an evidence base that is largely Russian-language and not independently replicated; Noopept is prescribed in Russia and is an unapproved new drug in the United States, with a thin, largely developer-authored trial base. No study has examined this combination, and for a pair where neither component has a replicated effect, a combined effect cannot be inferred from adding two uncertain ones. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026with Cerebrolysin
Overlapping neuroactive claims, none independently replicatedSemax and Cerebrolysin are commonly combined for cognitive or mood effects and are described as acting on overlapping neurotrophic and monoaminergic signalling rather than on separate targets. The shared problem is evidential rather than mechanistic: Semax is registered in Russia with an evidence base that is largely Russian-language and not independently replicated; Cerebrolysin is a porcine brain-derived peptide mixture whose Cochrane review found probably little or no benefit on all-cause death in acute ischaemic stroke, alongside moderate-quality evidence of a potential increase in non-fatal serious adverse events. No study has examined this combination, and for a pair where neither component has a replicated effect, a combined effect cannot be inferred from adding two uncertain ones. Peppy reports curated pharmacology, not a safety verdict. A prescriber or pharmacist should review any intended combination.
Reviewed 21 Aug 2026HUMAN EVIDENCE
Semax is registered and used clinically in Russia for stroke and cognitive indications, but the trials supporting that are largely Russian-language, conducted by or near the originating institute, and have not been independently replicated to Western regulatory standards. The closest thing to a controlled human result curated here is a small placebo-controlled imaging study in healthy volunteers reporting short-term changes in a resting-state brain-network measure - a change in an imaging signal, not a clinical benefit. The mechanistic literature is rat. No Western regulator has evaluated it.
REPORTED EFFECTS
Systematic adverse-effect data from controlled trials is not available in the indexed literature. Semax acetate was added to FDA's Category 2 interim compounding list in September 2023 as a substance that may present significant safety risks. No regulator has approved this substance for the use described here, so there is no label-verified dose, purity standard, or safety monitoring requirement behind it.
RESEARCH LIMITATIONS
Available findings are narrow and do not establish efficacy, long-term safety, or a general nootropic effect. No dosing or protocol recommendation is provided.
CURATED SOURCES · 4