Semax

A synthetic ACTH-fragment analogue developed in Russia for neurologic research.

Early human evidencePeptide research profile

Also known as: ACTH(4-7)-Pro-Gly-Pro, MEHFPGP

Sources reviewed October 1, 2026 (how we review)

Dosing & scaling, explained

The 200 mcg daily calculator row is not the route or exposure used in the best-known human Semax reports, which are predominantly intranasal. This is educational source context, not a protocol or recommendation.

How sourced amounts are organized

Starting pointNot clinically establishedNo validated titration window
There is no regulator-approved starting dose for this research use. A low-looking number is not automatically safe.
Recorded preset200 mcg / dayCalculator library reference
This is the range represented in the in-app protocol library. It describes the source record; it does not validate the regimen.
Higher exposureNo injectable ceiling establishedRisk and uncertainty increase
Higher exposure is not established as more effective. Human pharmacokinetic and long-term safety data may be absent.

Published Semax studies may report micrograms per kilogram, total milligrams, or nasal solution concentration; these measures are not interchangeable.

Patterns described in source material

Daily in the recorded preset
The cadence represented by the recorded calculator presets.
Intranasal multi-day courses in stroke reports
Published experiments may use a different route, formulation, timing, or population and should not be treated as interchangeable.
No universal schedule
No single schedule has been validated across products or research contexts.

Clinical context

Human studies do not validate a general wellness or injectable protocol.

Storage, handling and interpretation

Lyophilized material

Keep cold, dry, and protected from light according to the manufacturer certificate or validated lab SOP.

After reconstitution

Use sterile technique, refrigerate as validated, and avoid repeated freeze-thaw cycles.

Traceability

Record lot, concentration, preparation date, and the identity/purity documentation used by the lab.

Reported protocols for Semax

What published studies and recent community write-ups report about amounts, timing and course length. 6 clinical, 1 preclinical and 3 community-reported rows, each linked to its source. These are descriptions of what others report, not instructions, and nothing here is medical advice.

Context	Dose	Frequency	Route	Course	Source
Clinical6 rows
Registered Russian label, Semax 0.1% nasal dropsAdults with discirculatory encephalopathy or transient cerebrovascular events, as the registered indications are written	Single dose 200-2,000 mcg (3-30 mcg/kg); daily total 800-8,000 mcg (7-70 mcg/kg). One drop contains 50 mcg	2 to 3 drops into each nostril, 4 times a day	Intranasal drops	10-14 daysThe label states the course may be repeated if needed, without specifying a gap	Community resource2011
The same label sets out shorter schedules for other indications: 1,400-3,500 mcg three times daily for 3 to 5 days after head injury, neurosurgery or anaesthesia, 400-900 mcg per day for 3 to 5 days in the first half of the day to improve adaptation and prevent mental fatigue, and 600-900 mcg per day for 7 to 10 days in optic nerve disease. Absorption from the nasal mucosa is given as 60% to 70% of the active substance.
Registered Russian label, Semax 1% nasal drops for strokeAdults in the acute period of moderate or severe ischemic stroke, as part of combined therapy	Moderate stroke: 2,000-3,000 mcg per administration, 6,000-12,000 mcg per day. Severe stroke: 3,000-4,000 mcg per administration, 12,000-20,000 mcg per day. One drop contains 500 mcg	3 to 4 times daily at 3 to 4 hour intervals for moderate stroke; 4 to 5 times daily at 2.5 to 3 hour intervals for severe stroke	Intranasal drops, 2 to 4 drops per nostril per administration	10 daysNone; the course is a single 10-day inpatient block	Community resource2011
This is a prescription-only product and the strength is ten times the nootropic solution, so the same number of drops delivers ten times the dose. The label contraindicates it in anyone under 18, in acute psychiatric and anxiety disorders, in pregnancy and lactation and with a history of seizures, and reports that no overdose phenomena have been identified even at substantially increased single doses.
Acute hemispheric ischemic stroke study30 patients in the acute period of hemispheric ischemic stroke, compared with 80 patients on conventional therapy	12 mg per day for moderate strokes and 18 mg per day for severe strokes	Daily, added to combined intensive therapy	Intranasal	5 days and 10 daysNot applicable	Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (PubMed)1997
The authors reported faster regression of general cerebral and focal deficits, particularly motor deficits, with EEG mapping and somatosensory evoked potentials used to track brain function. The control group was not randomized and the study is small, which is the pattern across the Russian stroke literature on this compound.
Russian full report of the acute stroke study30 patients dosed from the first hours of stroke onset	12, 18 or 24 mg per day, described as averaging 150, 260 and 300 mcg/kg	Split into two administrations per day	Endonasal, 4 drops in saline with 2 drops per nostril	Dosing through the acute period, with brain function monitored on arrival and again on day 6Not applicable	Neurology Bulletin (Eco-Vector)1997
The Russian-language report names a 24 mg per day arm that the English abstract omits, and gives the per-kilogram equivalents and the two-dose-a-day schedule. Patients received a deliberately uniform baseline therapy without metabolic drugs so that any difference could be attributed to the peptide.
Post-stroke rehabilitation courses110 adults after ischemic stroke, mean age 58, split into early and late rehabilitation groups	6,000 mcg per day	Daily	Intranasal	Two 10-day courses separated by a 20-day interval20 days between the two courses	Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (PubMed)2018
Plasma BDNF rose and stayed elevated for the whole study period in the treated subgroups, and Barthel index recovery was faster. No blinding or placebo arm is described, so the course structure is better evidenced than the effect; this two-course pattern is the origin of most community cycling advice.
Meta-analysis of Russian acute stroke studies654 patients across 8 eligible studies, of which 3 studies and 181 patients met the inclusion criteria	12-18 mg per day of the 1% intranasal solution	Daily during the first 10 to 14 days	Intranasal	10-14 days, with outcomes read at days 10 to 14 and day 21Not applicable	Bulletin of Rehabilitation Medicine (Eco-Vector)2018
Pooling found lower NIHSS scores at days 10 to 14 and day 21 in the moderate and severe subgroups and better Rivermead mobility across all subgroups, but heterogeneity was very high and only three of the identified studies could be combined. The authors concluded that a properly powered multicentre double-blind trial is still needed.
Preclinical1 row
Preclinical single-dose BDNF studyAdult male Wistar rats	50 mcg/kg, with a tested range of 0.5-500 mcg/kg	Single application	Intranasal	Hippocampus sampled at 3, 6, 24 and 48 hoursNot applicable	Brain Research (PubMed)2006
One dose produced a maximal 1.4-fold rise in hippocampal BDNF protein, a 1.6-fold rise in trkB phosphorylation and roughly 3-fold and 2-fold rises in BDNF exon III and trkB messenger RNA, alongside more conditioned avoidance responses. Both 50 and 500 mcg/kg raised BDNF protein by the same 1.4-fold, so the response did not scale with dose.
Community-reported3 rows
Community nootropic course	200-600 mcg per administration of the 0.1% solution, about 2 to 6 drops per nostril	2 to 3 times daily, morning and early afternoon only	Intranasal	10-14 days2-4 weeks off, with 2 to 4 courses a year described for chronic complaints	Community resource2026
This 2026 page reproduces the Russian cognitive schedule and adds a cycling rationale based on avoiding receptor desensitisation, while conceding the evidence for that rationale is limited. It flags glucose monitoring because a rise in blood glucose has been reported in roughly 7% of diabetic patients under Russian clinical observation, and advises against late-evening dosing.
Community dosing table by indication	200-600 mcg per day for cognitive use; 600-900 mcg per day for cognitive impairment; 200-1,000 mcg per day for the subcutaneous research route	2 to 3 times daily intranasally, or once to twice daily subcutaneously, with the last dose before 14:00	Intranasal spray or subcutaneous from reconstituted powder	10-14 days to match Russian clinical protocols7-14 days off between courses	Community resource2026
This 2026 guide separates the 0.1% cognitive doses from the 1% stroke doses, which it lists at 9-18 mg per day under hospital protocols, and argues the two should never be confused. It states the compound is not FDA-approved and reports that an FDA advisory briefing in July 2026 recommended against adding it to the list of compoundable substances, citing thin human data.
Community chart built around the concentration error	100-200 mcg per day to start, 200-600 mcg per day standard, 600-1,000 mcg per day upper range, all using the 0.1% solution	Often a single morning dose of 2 to 6 sprays at 100 mcg per spray	Intranasal	5-7 days for a first course, 10-14 days for a standard course10-14 days off, matched to the on period	Community resource2026
The central warning on this page is that confusing the 0.1% and 1% solutions is a tenfold dosing error in either direction, and that a pump delivering 0.1 mL gives 100 mcg at 0.1% but 1,000 mcg at 1%. It attributes the 0.25-1.0 mg single-dose cognitive range to a 1996 double-blind trial that it notes is not indexed in PubMed, and describes the fading of effects at two weeks as an assumption rather than a measurement.

How a course is commonly described

First hourCommunity-reported
Community reports place noticeable effects 30 to 60 minutes after a morning dose, which fits delivery along the olfactory route rather than through the bloodstream. Plasma clearance is fast, so the effect is not explained by circulating drug levels.
Days 1-5Clinical
The registered 0.1% label uses a 3 to 5 day block at 400-900 mcg per day, taken in the first half of the day, for adaptation and prevention of mental fatigue. This is the shortest course on the label and the closest official analogue of nootropic use.
Days 10-14Clinical
The cerebrovascular and cognitive indications on the 0.1% label run 10 to 14 days at 800-8,000 mcg per day, and community nootropic courses copy that length. The label permits repeating the course when needed but does not define a gap.
BreakCommunity-reported
Community guides stop after 10 to 14 days and pause for 2 to 4 weeks, often running 2 to 4 courses a year. The stated reason is that the BDNF response normalises under continuous dosing, which nobody has measured in people.
Rehabilitation comparisonClinical
The largest post-stroke study used two 10-day courses at 6,000 mcg per day with a 20-day gap, roughly ten times the cognitive dose, and tracked plasma BDNF and Barthel index rather than subjective focus. The acute stroke protocols are higher again at 12,000-20,000 mcg per day for 10 days under supervision.

The 0.1% and 1% solutions differ tenfold in strength, and the same drop count delivers 50 mcg from one bottle and 500 mcg from the other. The 1% product is prescription-only in Russia and registered solely for acute ischemic stroke.
Almost all human evidence is Russian-language, small and produced by or near the institute that developed the compound. A 2018 meta-analysis could combine only three studies totalling 181 patients and called for a proper multicentre double-blind trial.
Semax has no FDA or EMA approval, and the 1% label itself contraindicates it in anxiety disorders, acute psychiatric illness, a history of seizures, pregnancy and anyone under 18, which is worth noting given how it is marketed abroad.

Sources for this section (11)

Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (PubMed)1997Clinical
Usage of the neurospecific peptide substance semax in the acute period of ischemic insult (Russian)Neurology Bulletin (Eco-Vector)1997Clinical
The efficacy of semax in the treatment of patients at different stages of ischemic strokeZhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova (PubMed)2018Clinical
Meta-analysis: Semax effectiveness in the acute period of strokeBulletin of Rehabilitation Medicine (Eco-Vector)2018Clinical
Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampusBrain Research (PubMed)2006Preclinical

Plus 6 community resources (dosing guides, forum threads and vendor write-ups), reported above but not linked.

Overview

Semax is a synthetic seven-residue peptide built at the Institute of Molecular Genetics of the Russian Academy of Sciences by joining the adrenocorticotropic hormone fragment 4-7 to a proline-glycine-proline tail that resists peptidases. It is registered as a medicine only in Russia, in two strengths that are used for quite different purposes: Semax 0.1% nasal drops, an over-the-counter nootropic registered in December 2011 for cognitive and cerebrovascular complaints, and the prescription-only Semax 1% drops registered the same month for the acute period of moderate to severe ischemic stroke. Published work is dominated by Russian-language studies from the group that developed the compound, with rodent evidence that a single dose raises hippocampal BDNF and trkB expression. Outside Russia it is sold as an unapproved research chemical and used as a self-administered nootropic, an application with no clinical support.

What researchers are exploring

These themes describe recurring questions in published research. They are not claims of effectiveness or recommendations for use.

1
Ischemic stroke
Regional clinical studies examine neurologic recovery when added to standard care.
2
Neurotrophin signaling
Animal and cell research measures BDNF, TrkB, and related transcription.
3
Brain-network effects
Small placebo-controlled imaging work examines resting-state connectivity.
4
Neuroprotection
Preclinical models include ischemia, oxidative stress, and dopaminergic injury.

What the current evidence can support

Study models remain visible so laboratory and animal findings are not mistaken for established human outcomes.

Human
Small stroke clinical reports
A 1997 study used non-randomized controls and reported faster regression of selected deficits.
Human
Healthy-volunteer imaging
Small controlled fMRI work found changes in resting-state network signals, not clinical outcomes.
Animal
BDNF-linked mechanism studies
Rodent studies report changes in neurotrophin expression after Semax.

Amounts recorded for Semax

These amount records are independent from vial strength, reconstitution volume and measuring device. A recorded source is not the same as study backing, and these values are not recommendations.

1
Standard Dose Range · lower endpointSign in for schedule, duration and source context.
100 mcg
2
Recorded referenceSign in for schedule, duration and source context.
200 mcg
3
Standard Dose Range · upper endpointSign in for schedule, duration and source context.
500 mcg

Chemistry identifiers

Sequence, synonyms and registry identifiers as recorded in PubChem, the National Library of Medicine's open chemistry database. Formula, mass and CAS number are summarized at the top of the page.

Sequence

Met-Glu-His-Phe-Pro-Gly-Pro

Also listed as

Semax, ACTH (4-7), Pro-Gly-Pro, MEHFPGP, Met-Glu-His-Phe-Pro-Gly-Pro, UNII I5FAL2585H, HY-P1146, H-Met-Glu-His-Phe-Pro-Gly-Pro-OH, MFCD01631262

InChIKey

AFEHBIGDWIGTEH-AQRCPPRCSA-N

Origin / design

ACTH(4-7) extended with Pro-Gly-Pro

IUPAC name

(2S)-1-[2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-amino-4-methylsulfanylbutanoyl]amino]-4-carboxybutanoyl]amino]-3-(1H-imidazol-5-yl)propanoyl]amino]-3-phenylpropanoyl]pyrrolidine-2-carbonyl]amino]acetyl]pyrrolidine-2-carboxylic acid

Limitations and unknowns

Important limitations

The clinical literature is predominantly Russian and often falls short of modern trial-reporting standards.
Imaging and biomarker changes do not establish cognitive enhancement or stroke efficacy.
A calculator preset is a recorded research convention, not a recommendation or evidence of clinical benefit.
Identity, purity, sterility, and stability can vary substantially outside regulated manufacturing.
Route, formulation, and population can make results from one study inapplicable to another use.

Sources

3 curated references, each with its journal, year and study model, plus 6 community resources reported but not linked.

Effectiveness of Semax in the acute period of hemispheric ischemic strokeZhurnal Nevrologii i Psikhiatrii1997Human
Semax regulates BDNF and trkB expression in the rat hippocampusBrain Research2006Animal
Semax effects on the default mode network in healthy participantsNeuroscience and Behavioral Physiology2018Human

How sourced amounts are organized

Patterns described in source material

Storage, handling and interpretation

How a course is commonly described

What researchers are exploring

Ischemic stroke

Neurotrophin signaling

Brain-network effects

Neuroprotection

Small stroke clinical reports

Healthy-volunteer imaging

BDNF-linked mechanism studies

Sequence

Also listed as

InChIKey

Origin / design

Important limitations