Cognitive & neuro

Semax

A Russian-registered synthetic peptide derived from ACTH, used as a nasal spray for stroke recovery and cognitive disorders. Western evidence is minimal.

Limited evidenceApproved drugAdd to compare

What it is

Semax is a synthetic seven-amino-acid peptide based on the ACTH(4–10) fragment with an added tail that extends its stability. It is registered as a medicine in Russia for stroke recovery, optic nerve disorders and cognitive impairment, and sold as a nasal spray. It has not been approved by the EMA or FDA.

How it works

1
Animal studies report increased expression of BDNF and NGF, growth factors involved in neuron survival and plasticity.
2
Modulates monoamine turnover in the brain and inhibits enkephalin breakdown, which is proposed to affect mood and attention.
3
Unlike ACTH itself it does not appear to stimulate cortisol release, because the hormone-active part of the molecule is absent.
4
Shown to reduce oxidative stress markers in animal brain-injury models.

What it's studied for

Recovery after ischaemic stroke

Optic nerve disease and visual field loss

Cognitive impairment and attention

Transient ischaemic attacks

Attention deficit in children (small Russian studies)

Reported and studied effects

Russian trials report faster neurological recovery and higher cognitive scores
Improved visual acuity in some optic nerve studies
Increased BDNF measured in animal brains
Sample sizes are small and independent replication outside Russia is essentially absent

Research protocol notes

Research context only

Research context only — in Russia it is prescribed as a 0.1% nasal solution in short courses set by a physician. Western research has no standard protocol, and internet regimens are not clinically validated.

These figures are described so you can understand what researchers did. They are not a dose, a schedule, or a suggestion — and they are not a substitute for a doctor.

Possible side effects and contraindications

Safety profile

Possible side effects

Reported as well tolerated in Russian studies
Nasal irritation and dryness
Headache
Transient anxiety or irritability reported occasionally
Independent long-term safety data are unavailable

Contraindications and cautions

Hypersensitivity to the peptide
Pregnancy and breastfeeding
History of seizures or psychosis requires medical advice
Concurrent psychiatric medication should be reviewed by a doctor

A side-effect list is never complete, and these are not the only situations that warrant caution. Anything unexpected, or anything you are unsure about, should be discussed with a doctor before use.

Evidence assessment

Limited evidenceSmall human studies or animal data only

Small human studies or animal data only

There are published clinical studies, but they are small, largely from a single country, and have not been independently replicated in large randomised trials.

References

References link to published literature, regulator pages or literature indexes. Where a link points to a search, it collects the peer-reviewed work on that molecule rather than a single study.

Compare Semax with another peptide →

Related peptides

Other entries in Cognitive & neuro.

All Cognitive & neuro peptides →

Cognitive & neuro

ACTH 4-10 (Org 2766)

The nerve-acting fragment of ACTH, developed as a drug candidate for nerve damage and cognitive decline, and abandoned.

Limited evidenceInvestigational

Cognitive & neuro

BDNF (brain-derived neurotrophic factor)

The brain's main growth factor for plasticity: essential, widely measured, and not something a supplement can deliver.

Anecdotal evidenceNot approved

Cognitive & neuro

Cerebrolysin

A porcine brain peptide mixture licensed in parts of Eastern Europe and Asia for stroke and dementia, without EMA or FDA approval.

Limited evidenceInvestigational