Semax is a synthetic seven-amino-acid peptide based on a fragment of the hormone ACTH, developed in Russia and studied for stroke recovery and brain function. It is registered as a medicine in Russia but not approved by the FDA, and its research comes almost entirely from a few Moscow institutes.
Not FDA-approved
Human trials
Also known as Met-Glu-His-Phe-Pro-Gly-Pro, MEHFPGP, ACTH(4-7)PGP, ACTH(4-10) analogue
Written by Upzo editorial team
Legal status
Not FDA-approved for any use.
Checked on Oct 26, 2026
Example vials
5 mg · 10 mg
5 mg + 2 mL
2,500 mcg/mL
Per U-100 unit
25 mcg
Studies in library
8
01
What is Semax?
Semax is a chain of seven amino acids, Met-Glu-His-Phe-Pro-Gly-Pro (Dolotov 2006). The first four come from ACTH, a pituitary hormone (positions 4 to 7), and the last three (Pro-Gly-Pro) are an added tail. It is described as an analogue of the ACTH(4-10) fragment and is usually given as nose drops.
It was developed in Moscow, and its research is concentrated in a few Russian institutes, in particular the Institute of Molecular Genetics of the Russian Academy of Sciences, where many of the laboratory studies were done. Most clinical papers are in Russian, with English abstracts. In Russia it is registered as a prescription medicine (0.1% nasal drops), according to the Russian Vidal drug reference. We could not find approval by the FDA, the European Medicines Agency or any other Western regulator, or any trial run outside Russia.
Outside Russia it is sold online as a "nootropic research peptide", in nasal sprays and injectable powders that no regulator checks (Vanhee 2020).
Type: synthetic peptide, 7 amino acids (ACTH 4-7 plus Pro-Gly-Pro).
Studied for: recovery after ischaemic stroke, chronic poor blood flow to the brain, and cognition.
Strongest evidence: Russian clinical studies of stroke patients, published in Russian, with unclear randomisation and no placebo reported in the abstracts.
Legal status: registered as a medicine in Russia; not approved in the US.
02
Semax protocols and supplies
Schedules reported for this peptide, with the syringe measure for each step and the supplies each one takes. Reported use is not evidence that a schedule works or is safe, and none of this is medical advice.
Intranasal, 2 to 3 times a day
Intranasal spray, 3 times a day
Community-reported
Reported in the research community. It has not been tested as a schedule in human trials. Worked out with a 10 mg vial made up to 10 mL of sterile saline (1 mg/mL, 100 mcg per 0.10 mL spray). Usually taken in the first half of the day. Supplies are worked out for 3 times a day.
Amounts as reported, with the syringe or spray measure for the vial below. Not a recommendation.
Period
Amount each time
Sprays (0.10 mL)
Volume
Days 1-5
200-300 mcg
2-3
0.2-0.3 mL
Minimum supplies, worked out from the amounts above. Add a margin for losses.
Item
5 days
Doses
15
Total peptide
4.5 mg
Semax vials (10 mg)
1
Sterile saline
10 mL
Nasal spray bottles (one per vial)
1
03
Semax doses used in studies
The dose each published study gave its participants, copied from the paper. Not dosing instructions; animal doses do not convert directly to people.
At a glance: 8 studies report a dose (4 in people, 4 in animals).
Doses used in human studies
Gusev EI 2018: 6000 µg per day, in two 10-day courses separated by 20 days (About 5 months of follow-up)
Serdiuk AV 2007: 12 mg per day intranasally, in two 10-day courses with a 2-week break (Intranasal, 1% solution; 48 days of assessment)
Lebedeva IS 2018: 1% Semax solution intranasally (14 people) or placebo (10 people); amount not given in the abstract (Intranasal, 1% solution; Single dose; scans before and 5 and 20 minutes after)
Every study
Doses as reported by each study. Not a recommendation.
What has been studied, by type of evidence. A result in animals or cells is a reason to study something in people, not proof that it works in people.
In humans
Summarised
The human studies we could verify in PubMed are all Russian, and most are published in a Russian-language journal:
Stroke rehabilitation: in 110 patients after ischaemic stroke, those given Semax had higher blood levels of BDNF (a nerve growth factor) and better scores on a daily-living scale than those not given it (Gusev 2018).
Chronic poor blood flow to the brain: in 187 patients, Semax was reported to improve symptoms and lower the risk of stroke and transient ischaemic attacks, and to be well tolerated (Gusev 2005).
Motor neuron disease: in an open-label study of 27 patients, Semax did not change nerve damage measures or functional scores, but quality-of-life scores improved (Serdiuk 2007).
Healthy volunteers: brain scans in 24 adults showed changes in a resting brain network within 20 minutes of a nasal dose, compared with placebo (Lebedeva 2018).
Verdict: the human evidence comes from a few Moscow groups, uses small or unclearly controlled designs, and has not been repeated outside Russia. The abstracts of the stroke studies do not describe random allocation or a placebo group. Whether Semax improves stroke recovery or cognition has not been shown in trials that meet international standards.
In animals
Summarised
Brain growth factors
In rats, a single dose raised levels of BDNF and activated its receptor, trkB, in the hippocampus, a brain area involved in memory, and rats learned an avoidance task better (Dolotov 2006).
Stroke models
In rats with a blocked brain artery, Semax increased the activity of genes for nerve growth factors and their receptors in the damaged cortex (Dmitrieva 2010) and changed the activity of many genes linked to the immune and blood vessel systems (Medvedeva 2014). These studies measure gene activity, not recovery of function.
In cells (in vitro)
Nothing yet
No summary in our library yet. We only publish one after checking it against the original papers.
Proposed mechanisms from cell and animal studies. A plausible mechanism is not evidence of an effect in people.
No mechanism has been established. The Russian studies point to effects on nerve growth factors and immune signalling, shown mainly in rats:
BDNF and trkB: it raised BDNF protein and activated the trkB receptor in rat hippocampus (Dolotov 2006), and stroke patients given it had higher blood BDNF (Gusev 2018).
Nerve growth factor genes after stroke: it increased transcription of BDNF, NGF and their receptors in ischaemic rat cortex (Dmitrieva 2010).
Immune and vascular genes: after experimental stroke, more than half of the genes it affected were related to the immune response (Medvedeva 2014).
06
Reconstitution
How concentration changes with the amount of liquid added. A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. Step-by-step guide.
Step by step
Wash your hands and work on a clean, uncluttered surface. Let a refrigerated vial reach room temperature so the stopper is easier to pierce.
Wipe the rubber stopper of the peptide vial and of the bacteriostatic water with a fresh alcohol swab, and let them air-dry.
Draw the chosen volume of bacteriostatic water into a sterile syringe. With 2 mL, a 5 mg vial ends up at 2,500 mcg/mL, or 25 mcg per U-100 unit.
Insert the needle through the stopper and let the water run slowly down the inside wall of the vial, not straight onto the powder.
Swirl or roll the vial gently until the powder dissolves. Do not shake it: foaming can damage some peptides.
Check the solution against the light. It should be clear; cloudiness or particles mean something is wrong with the vial or the water.
Write the date and the volume of water on the label. Every unit calculation later depends on that volume.
Store the reconstituted Semax vial in the refrigerator, away from light.
Concentration by volume
Concentration after adding the liquid, and how much peptide each U-100 unit (0.01 mL) holds.
Vial
Liquid added
Concentration
Per unit
5 mg
1 mL
5,000 mcg/mL
50 mcg
5 mg
2 mL
2,500 mcg/mL
25 mcg
5 mg
3 mL
1,667 mcg/mL
16.7 mcg
10 mg
1 mL
10,000 mcg/mL
100 mcg
10 mg
2 mL
5,000 mcg/mL
50 mcg
10 mg
3 mL
3,333 mcg/mL
33.3 mcg
Reconstitution calculator
Arithmetic only. It assumes the vial holds exactly what the label says.
Concentration
2,500 mcg/mL
Per U-100 unit
25 mcg
Volume for your amount
—
07
Measuring with a U-100 syringe
What each mark on an insulin syringe holds once the vial is mixed. This is arithmetic, not a dose.
Reading a U-100 syringe: how much peptide each mark holds in a 5 mg vial mixed with 2 mL. Not a dose.
Syringe mark
Volume
Peptide in that volume
5 units
0.05 mL
125 mcg
10 units
0.1 mL
250 mcg
20 units
0.2 mL
500 mcg
25 units
0.25 mL
625 mcg
50 units
0.5 mL
1.25 mg
100 units
1 mL
2.5 mg
A U-100 insulin syringe holds 1 mL in 100 units, so each unit is 0.01 mL. The marks measure volume, not peptide.
Syringes come in 0.3 mL (30 units), 0.5 mL (50 units) and 1 mL (100 units) sizes. The smaller ones have finer marks and are easier to read for small volumes.
Read the volume at the top edge of the plunger's rubber seal, at eye level.
Tap out air bubbles before reading: a bubble takes up volume and makes the reading wrong.
Use a new sterile syringe and needle every time, and dispose of them in a sharps container.
08
Supplies
What reconstituting and measuring a vial takes.
The peptide vial, with its certificate of analysis (COA) for that batch. See how to read a COA.
Bacteriostatic water (water with 0.9% benzyl alcohol), which keeps a multi-use vial from growing bacteria. Sterile water has no preservative.
Sterile syringes to add the water, and U-100 insulin syringes to measure.
Alcohol swabs for the stoppers.
A sharps container for used needles.
A label or marker to write the date and the volume of water on the vial.
09
Side effects, safety and legal status
Side effects and long-term safety are not well documented outside the Russian literature. One study reported few side effects, including in older patients (Gusev 2005), but the studies are small and were not designed to detect uncommon problems.
Product quality: Semax sold online is not checked by any regulator. A Belgian control laboratory identified it in seized preparations of unknown content and warned that such peptides are freely sold as injectable powders and nasal sprays (Vanhee 2020).
Hormone fragment: it is built from part of ACTH, a stress hormone. We could not find studies that checked whether it affects the body's own hormone system in people.
Injection risks: the registered Russian product is a nasal drop. Injectable powders sold online add the risk of infection if they are not sterile.
FDA
Not FDA-approved for any use.
Status checked on
Oct 26, 2026
10
Storing Semax
Before mixing
Freeze-dried (lyophilised) peptide is the most stable form. It is usually kept refrigerated, or frozen for long storage, sealed and away from light.
Heat, moisture and light speed up degradation. Keep the vial in its box and avoid leaving it in a car or by a window.
After mixing
Keep the reconstituted vial refrigerated and away from light. Do not freeze it again: freezing and thawing a solution can break the peptide down.
How long a mixed vial stays good depends on the peptide and the diluent, and for most research peptides there is no published stability data. Follow the supplier's guidance and discard any vial that turns cloudy.
Pierce the stopper as few times as possible, and always with a new sterile needle after wiping it with alcohol.
Write the volume of water on the label (for example "2 mL"). Without it, the unit calculations cannot be checked later.
11
Questions about Semax
Is Semax FDA-approved?
Not FDA-approved for any use.
What doses of Semax have been studied?
Our library has 8 studies on Semax. The doses each one used are in section 03, next to the study. They are not dosing instructions.
How much Semax is in each syringe unit?
It depends on how much liquid is added to the vial. For a 5 mg vial with 2 mL, each U-100 unit holds 25 mcg. The reconstitution table and calculator work it out for other volumes.
Is Semax approved anywhere?
It is registered as a prescription medicine in Russia, as nasal drops. We could not find approval by the FDA, the European Medicines Agency or other Western regulators.
Is Semax the same as ACTH?
No. It contains a short piece of ACTH (four amino acids) plus a three-amino-acid tail. It is not the full hormone. The Russian studies focus on its effects on brain growth factors; we could not find studies that checked whether it affects the body's own stress hormone system in people.
How strong is the evidence for Semax in stroke?
It rests on Russian studies whose abstracts do not describe random allocation or placebo control. No independent trial outside Russia has been published, so its effect on stroke recovery is uncertain.
How much bacteriostatic water goes into a 5 mg Semax vial?
There is no single correct volume: it only changes the concentration. For a 5 mg vial, 1 mL gives 5,000 mcg/mL, 2 mL gives 2,500 mcg/mL, 3 mL gives 1,667 mcg/mL. More water makes small amounts easier to measure; less water keeps volumes small. Whatever volume is used, write it on the label.
What does one unit on an insulin syringe mean?
On a U-100 syringe, 100 units = 1 mL, so one unit is 0.01 mL. How much peptide that holds depends on the concentration of the vial, which depends on how much water was added.
Can doses from animal studies of Semax be converted to people?
No. Animal doses are reported per kilogram for a different species, and scaling them to people is not reliable. That is why Upzo shows each study dose next to its study, unconverted.
How should Semax be stored?
Unopened freeze-dried vials are usually kept refrigerated and away from light. Once mixed, keep the vial refrigerated and follow the supplier's guidance on how long it lasts.
12
References
The occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations: An incentive for controlling agencies to prepare for future encounters of the kind. Vanhee C, Francotte A, Janvier S, et al. Drug Testing and Analysis. 2020;12:371-381. doi:10.1002/dta.2717
The efficacy of semax in the treatment of patients at different stages of ischemic stroke. Gusev EI, Martynov MY, Kostenko EV, et al. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2018;118:61-68. doi:10.17116/jnevro20181183261-68
Semax in prevention of disease progress and development of exacerbations in patients with cerebrovascular insufficiency. Gusev EI, Skvortsova VI, Chukanova EI. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2005;105:35-40. PMID 15792140
The study of chronic partial denervation and quality of life in patients with motor neuron disease treated with semax. Serdiuk AV, Levitskiĭ GN, Miasoedov NF, et al. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova. 2007;107:29-39. PMID 18379501
Effects of Semax on the Default Mode Network of the Brain. Lebedeva IS, Panikratova YR, Sokolov OY, et al. Bulletin of Experimental Biology and Medicine. 2018;165:653-656. doi:10.1007/s10517-018-4234-3
Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus. Dolotov OV, Karpenko EA, Inozemtseva LS, et al. Brain Research. 2006;1117:54-60. doi:10.1016/j.brainres.2006.07.108
Semax and Pro-Gly-Pro activate the transcription of neurotrophins and their receptor genes after cerebral ischemia. Dmitrieva VG, Povarova OV, Skvortsova VI, et al. Cellular and Molecular Neurobiology. 2010;30:71-79. doi:10.1007/s10571-009-9432-0
The peptide semax affects the expression of genes related to the immune and vascular systems in rat brain focal ischemia: genome-wide transcriptional analysis. Medvedeva EV, Dmitrieva VG, Povarova OV, et al. BMC Genomics. 2014;15:228. doi:10.1186/1471-2164-15-228
Research and education only. Not medical advice. Many peptides on this site are not approved by the FDA for human use. Doses shown are the ones used in published studies and are not a recommendation. Talk to a licensed clinician before using any of them. Read the full disclaimer.