Semax
Also known as ACTH (4-10) analog, Semax heptapeptide
Last reviewed · Awaiting clinical review
Main safety concerns
Widely used in Russia but barely studied in Western trials. Usually taken as nose drops. It may cause mild anxiety, and the Russian label rules it out for people with anxiety disorders or a history of seizures.
- SeriousAvoid if: Pregnancy or breastfeeding
- WarningAvoid if: Anxiety disorders, acute psychiatric illness, or a history of seizures
Educational information, not medical advice. If you have symptoms that worry you, contact a clinician or emergency services.
What is known
A Russian nootropic peptide, used intranasally for focus, memory, and recovery from stroke.
On this page
What it is and how it works
Semax is a short peptide based on a fragment of ACTH, a natural hormone, but changed so it does not act like a stress hormone. In animals it raises BDNF, a growth factor that helps neurons survive, and in stroke patients it raised BDNF in the blood. It is a registered prescription medicine in Russia for stroke and memory problems. It is usually given as nose drops, which sends it toward the brain while skipping the stomach.[1] [2] [4]
Evidence by claim
Each claim is graded on its own. Tap a grade to see what it does and does not mean.
Helped recovery after stroke, and memory problems from poor brain blood flow, in small Russian studies.
Source type: Cohort study, Regulatory record
Mostly small Russian studies without placebo. FDA judged the evidence insufficient in 2026.
Raises BDNF in the brain in animals.
Source type: Animal study
Well replicated in animals, which is the mechanistic basis for most claims.
[2]Dolotov OV et al. (Brain Research) 2006 (opens source in a new tab)· Animal studyImproved attention and short term memory in one small trial in healthy workers.
Source type: Randomized trial
Sixteen men, one 1 mg dose, effects lasting about a day. The authors noted a possible mild anxiety effect.
Reported side effects
- CautionMild nasal irritation with long use(uncommon)[4]
- CautionPossible mild anxiety or edginess(uncommon)[5] [4]Suggested in a small trial at a single 1 mg dose. The Russian label rules it out for anxiety disorders.
- InfoLittle published safety data[3] [5]FDA found almost no adverse event reporting in the studies it reviewed. A small trial found no notable change in blood pressure.
Interactions and combination risks
It may add mild edginess. Combinations have not been studied.
Who should avoid it
- SeriousPregnancy or breastfeeding
No safety data in pregnancy or breastfeeding.
- WarningAnxiety disorders, acute psychiatric illness, or a history of seizures
Listed as reasons not to use it on the Russian label.
Dosing
Placed after the evidence and risks on purpose. Nothing here is a recommendation for you.
| Route(s) | intranasal (most common), subcutaneous |
|---|---|
| Typical range | The Russian label uses a 0.1 percent solution, about 50 mcg per drop. Adults take about 400 to 900 mcg a day for mental fatigue, and 800 to 8000 mcg a day for memory problems from vascular brain disease. A stronger 1 percent solution is used for stroke. |
| Frequency | Split through the day, in short courses |
| Cycle guidance | The Russian label uses courses of 10 to 14 days for memory problems, or 3 to 5 days for mental fatigue. |
| Notes | Most people use it as nose drops, not injection. For nasal use, what matters is the concentration in mcg per drop, not syringe units. FDA found no human studies of how long it lasts in the blood. |
For the equipment itself, see syringes, needles, and the rest of the kit.
Reconstitution
| Vial sizes | 5 mg, 10 mg |
|---|---|
| Diluent | Bacteriostatic or sterile water. Many people mix it for nasal use rather than injection. |
| Concentration | Example: a 5 mg vial plus 5 mL of water gives 1 mg/mL. For nasal use, work out mcg per drop from that. For subcutaneous use, a 300 mcg dose is 0.3 mL, which is 30 units on a U-100 syringe. |
| Notes | Sold as a lyophilized powder or as a ready made nasal spray. Powder is commonly 5 mg or 10 mg per vial. |
General reconstitution technique
Units and volume arithmetic
Converts between an amount and syringe units for the vial and diluent you enter. It starts empty and does not suggest an amount. Open the full calculator
Result
Fill in steps 1 to 3 to see the arithmetic. Nothing here is a suggested amount.
Settings live in the address bar, so a pasted link reopens this calculator as you left it.
Educational arithmetic only. It does not choose an amount for you and is not medical or dosing advice. Verify every calculation independently.
Storage and stability
Dry powder (lyophilized)
| Temperature | Freeze for long term storage, or 2 to 8 short term |
|---|---|
| Shelf life | Many months when frozen |
| Notes | Keep dry and out of light until you mix it. |
After mixing
| Temperature | 2 to 8 (refrigerated) |
|---|---|
| Shelf life | About 2 to 4 weeks |
| Notes | Do not freeze after mixing. Discard if cloudy or discolored. |
COA and purity notes
| Common adulterants | nasal sprays that vary in concentration, underdosed or mislabeled vials |
|---|---|
| Mislabeling | Nasal products vary in strength, so check the concentration. A recent third party COA helps confirm identity and purity. |
| Notes | Registered as a medicine in Russia, but not approved in the US. Research and gray market material is unregulated. |
Sources
[1]The efficacy of semax in the treatment of patients at different stages of ischemic stroke (in Russian)
Gusev EI et al. (Zhurnal Nevrologii i Psikhiatrii) 2018 (opens source in a new tab)· Cohort study[2]Semax, an analog of ACTH(4-10) with cognitive effects, regulates BDNF and trkB expression in the rat hippocampus
Dolotov OV et al. (Brain Research) 2006 (opens source in a new tab)· Animal study[3]FDA Briefing Document, Pharmacy Compounding Advisory Committee, July 23 to 24, 2026: Semax Related Bulk Drug Substances
U.S. Food & Drug Administration 2026 (opens source in a new tab)· Regulatory record[4]Semax nasal drops 0.1%: instructions for medical use, registration no. LS-002553 (in Russian)
Peptogen (manufacturer) 2017 (opens source in a new tab)· Manufacturer statement[5]Synthetic ACTH analogue Semax displays nootropic-like activity in humans
Kaplan AYa et al. (Neuroscience Research Communications) 1996 (opens source in a new tab)· Randomized trial[6]Semax in prevention of disease progress and development of exacerbations in patients with cerebrovascular insufficiency (in Russian)
Gusev EI et al. (Zhurnal Nevrologii i Psikhiatrii) 2005 (opens source in a new tab)· Cohort study
Last reviewed 8 July 2026 · editorial status: reviewed