Semax
Also called ACTH(4-10) analogue; Met-Glu-His-Phe-Pro-Gly-Pro
A seven-amino-acid peptide derived from ACTH and used clinically in Russia. Evidence that it changes lab or brain-scan measures is stronger than evidence it improves everyday focus or treats ADHD.
Overview
What it is
A synthetic heptapeptide based on a fragment of adrenocorticotropic hormone. It is not an ACTH replacement.
How it works
In rats, it raised BDNF (a nerve-cell support protein) and its receptor TrkB in the hippocampus, along with changes in a learning task.
What the research shows
Small Russian brain-imaging studies in healthy volunteers found changes in resting-state brain networks, possibly with overlapping participants. A 2018 Russian study looked at stroke patients. None show reliable improvement in daily focus.
Studied for
- BDNF signalingrats
- Brain network activitysmall imaging studies
- Stroke recoveryRussian clinical use
Safety and regulatory status
Safety and side effects
FDA's 2026 review found inadequate intranasal safety information and no data for injection, and flags immune reactions from aggregation and impurities. One report described eye pain and burning after a nasal product. "No side effects" claims are not supported.
Regulatory status
Not a component of any FDA-approved drug (FDA, 2026). On FDA's list of compounding substances with potential safety risks.
Mixing and dosing reference
Reference information only. Read before using this section.
Semax Dosage (5 mg Vial) Protocol
- Vial
- 5 mg Semax
- Add diluent
- 5 mL or 10 mL measured nasal solution
- Concentration
- 1 mg/mL (5 mL) or 0.5 mg/mL (10 mL)
- 1 unit (U-100)
- 100 mcg (5 mL) or 50 mcg (10 mL) per 0.10 mL spray
- Route
- Intranasal
- 5 mL final volume
- 1 mg/mL 100 mcg per verified 0.10 mL spray, and 50 nominal sprays.
- 10 mL final volume
- 0.5 mg/mL 50 mcg per verified 0.10 mL spray, and 100 nominal sprays.
- Primary human research route
- Intranasal drops or measured intranasal solution.
Semax 5 mg Nasal Spray Calculations
| Measured Final Volume | Vehicle Added After Transfer | Final Concentration | Per Verified 0.10 mL Spray |
|---|---|---|---|
| 5.0 mL | About 2.0 mL | 1,000 mcg/mL | 100 mcg50 nominal sprays |
| 10.0 mL | About 7.0 mL | 500 mcg/mL | 50 mcg100 nominal sprays |
Reference Schedule
| Period | Amount | Spray Volume | Frequency |
|---|---|---|---|
| Days 1–5 | 200–300 mcg per administration (400–900 mcg/day) | 0.20–0.30 mL at 1 mg/mL (2–3 verified 0.10 mL sprays) | 2–3 times in the first half of the day |
Research Amount to Spray Equivalents
| Research Amount | 5 mL Option100 mcg per Spray | 10 mL Option50 mcg per Spray |
|---|---|---|
| 200 mcg | 2 sprays | 4 sprays |
| 300 mcg | 3 sprays | 6 sprays |
| 400 mcg | 4 sprays | 8 sprays |
| 500 mcg | 5 sprays | 10 sprays |
Published Human Intranasal Semax Research
| Source | Research Context | Published Intranasal Amount and Formulation |
|---|---|---|
| Kaplan et al., 1996 | Healthy volunteers in operator and EEG experiments | Experiments included 0.25 mg and 1 mg exposures. The operator experiment reported 1 mg in 0.4 mL physiological solution. |
| Lebedeva et al., 2018 | Healthy volunteer fMRI study | One 1.2 mg exposure using a 1% solution, with 60 microliters placed into each nostril. |
| Gusev et al., 2018 | Condition-specific post-stroke research | 6,000 mcg per day for 10 days, followed by a second 10-day course after a 20-day interval. |
| Official 0.1% Semax instructions | Registered intranasal drop formulation | 1 mg/mL in purified water with methylparaben. Each 0.05 mL drop contained 50 mcg. |
Core Formula
| Verified Actuator Output | 5 mL Option1,000 mcg/mL | 10 mL Option500 mcg/mL |
|---|---|---|
| 0.05 mL | 50 mcg | 25 mcg |
| 0.10 mL | 100 mcg | 50 mcg |
| 0.13 mL | 130 mcg | 65 mcg |
How to mix
- Confirm the 5 mg vial, selected sterile research vehicle, actuator bottle capacity, and documented pump output.
- Add 3.0 mL of compatible sterile vehicle to the vial with aseptic transfer technique.
- Gently swirl until the contents are dissolved. Do not shake.
- Transfer the complete 3.0 mL solution into a sterile 5 mL or 10 mL nasal actuator bottle.
- Add enough vehicle to reach a measured final volume of exactly 5.0 mL or 10.0 mL. The theoretical additions are approximately 2.0 mL and 7.0 mL.
- Secure the pump and label the bottle with the peptide amount, final volume, concentration, pump output, and preparation date.
- Prime the pump according to the actuator instructions and record the priming sprays in the research log.
Protocol source: PeptideDosages.com
Common questions
Does Semax treat ADHD?
That has not been shown. ADHD has established treatments.
How quickly does it work?
Scan timing in studies is not a proven onset of better focus.
Is Semax the same as Selank?
No. They are different peptides.
Found in these blends
Related in Brain and Cognitive Health
Sources and further reading (5)
- Dolotov OV, et al. Semax regulates BDNF and TrkB in rat hippocampus. Brain Res, 2006.
- Effects of Semax on the default mode network. Bull Exp Biol Med, 2018.
- FDA. July 2026 Pharmacy Compounding Advisory Committee: Semax evaluation.
- NIMH. ADHD in adults.
- Source summary: PeptideDosages.com research overview (rewritten for NVO).
Laboratory research material: Semax Research Use Only