Updated August 2026
Semax Dosage: Research Evidence, Russian Label, and Study Protocol
Research note: Semax (MEHFPGP, MW ~813.93 Da) has Russian 0.1% and 1% intranasal products with tenfold concentration difference (~50 vs 500 mcg/drop). Mental-fatigue label: 400–900 mcg/day × 3–5 days. 1% stroke regimens (6–20 mg/day) must not be used as cognitive dosing. Healthy fMRI: 1.2 mg once — not daily precedent. No validated human SC dose in FDA 2026 review.
Semax is Met-Glu-His-Phe-Pro-Gly-Pro, developed from ACTH(4–7) with a Pro-Gly-Pro extension. It is distinct from full-length ACTH, N-acetyl Semax, N-Acetyl Semax Amidate, and Adamax.
Semax 0.1% = 1 mg/mL ≈ 50 mcg per 0.05 mL drop. Semax 1% = 10 mg/mL ≈ 500 mcg per drop. Confusing concentrations creates a tenfold dosing error.
Russian 0.1% instructions are indication-specific — mental fatigue/adaptation 400–900 mcg/day for 3–5 days is the strongest lower-dose anchor. Online 100–600 mcg per administration partly overlaps but often extends duration or switches to injection without evidence.
Semax dosage in 30 seconds
| Question | Current answer |
|---|---|
| Sequence | MEHFPGP · ~813.93 Da |
| 0.1% per drop | ~50 mcg (0.05 mL) |
| 1% per drop | ~500 mcg (tenfold) |
| Mental fatigue label | 400–900 mcg/day · 3–5 days |
| 1% moderate stroke | 6–12 mg/day · 10 days |
| fMRI healthy dose | 1.2 mg once |
| Online cognitive | 100–600 mcg/admin · anecdotal |
| Human SC dose | None validated |
Compound identity
Research must specify sequence, terminal modifications, free peptide vs salt, peptide content, concentration (mg/mL), and delivered volume per drop or actuation.
Identity gate
Semax (MEHFPGP) vs acetate · N-acetyl · amidated · Adamax
This page's subject — ACTH(4–7)-PGP analog MEHFPGP
MW ~813.93 Da · C37H51N9O10S · PubChem CID 9811102 · CAS 80714-61-0. Russian 0.1% and 1% intranasal medicinal products refer to unmodified Semax.
The tenfold concentration difference
0.1% and 1% are not “weak” vs “strong” consumer options — they serve different clinical contexts. 1% enables milligram-range acute-stroke exposure without impractically large drop counts.
Tenfold concentration split
0.1% (~50 mcg/drop) vs 1% (~500 mcg/drop) — same drop count, 10× exposure
| Drops | 0.1% total mcg | 1% total mcg | Ratio |
|---|---|---|---|
| 1 | 50 mcg | 500 mcg | 10× |
| 2 | 100 mcg | 1000 mcg | 10× |
| 4 | 200 mcg | 2000 mcg | 10× |
| 6 | 300 mcg | 3000 mcg | 10× |
| 8 | 400 mcg | 4000 mcg | 10× |
| 12 | 600 mcg | 6000 mcg | 10× |
Confusing 0.1% and 1% is the most common Semax dosing error — not a strength preference.
Drop-count dose mathematics
Drop calculator
Drops × concentration → mcg per administration
mcg per drop
50 mcg
Total (4 drops)
200 mcg
mg equivalent
0.200 mg
Assumes 0.05 mL per drop (50 mcg at 0.1%). Russian label limits large doses to 2–3 drops/nostril per administration.
Spray pumps and consumer droppers are not interchangeable with validated medicinal containers without delivered-dose measurement.
Regulatory context
No U.S. prescribing label. FDA July 2026 proposed neither Semax free base nor acetate for 503A bulks list — incomplete characterization, safety uncertainty, device/formulation gaps. Russian product history and U.S. compounding review answer different questions.
Russian Semax 0.1% indication schedules
Russian 0.1% product
Indication-specific intranasal schedules
| Context | Per dose | Frequency | Daily | Duration |
|---|---|---|---|---|
| Mental fatigue / adaptation | 2–3 drops/nostril | 2–3× first half of day | 400–900 mcg/day | 3–5 days |
| Vascular cognitive dysfunction | 200–2,000 mcg (3–30 mcg/kg) | 4× daily | 800–8,000 mcg/day | 10–14 days |
| Post-TBI / neurosurgery / anesthesia | 1,400–3,500 mcg (40–50 mcg/kg) | 3× daily | 4,200–10,500 mcg/day | 3–14 days |
| Optic-nerve disease (drops) | 2–3 drops/nostril | 2–3× daily | 600–900 mcg/day | 7–10 days |
| Pediatric MBD (age ≥7) | 1–2 drops/nostril | 2× morning/midday | 200–400 mcg/day | 30 days |
No more than 2–3 drops per nostril at once; larger doses split by 10–15 minutes.
Semax 1% acute stroke instructions
These are acute ischemic stroke product instructions — medical emergencies requiring standard stroke care. Not cognitive or nootropic precedents.
1% acute stroke product
6–20 mg/day regimens — medical emergency context only
Not cognitive or nootropic precedents. These are acute ischemic stroke product instructions requiring standard stroke care.
| Severity | Per dose | Frequency | Daily | Duration |
|---|---|---|---|---|
| Moderate ischemic stroke | 2,000–3,000 mcg | 3–4× daily | 6,000–12,000 mcg (6–12 mg) | 10 days |
| Severe ischemic stroke | 3,000–4,000 mcg | 4–5× daily | 12,000–20,000 mcg (12–20 mg) | 10 days |
Dosage in human clinical research
> Doses describe medicinal-product instructions or study exposure — not a universal prescribing protocol.
Human clinical research
250 mcg–20 mg/day by context · quality and purpose vary
| Study | Dose | Route | Duration | Purpose |
|---|---|---|---|---|
| Kaplan 1996n = 19 | 250 mcg once or 1 mg/day | IN | 1–2 days | Neurophysiologic/cognitive · limited AE detail |
| Panikratova 2020n = 14 | 1.2 mg 1% once | IN 60 µL/nostril | Single | fMRI connectivity · not repeated dosing |
| Gusev 1997n = Stroke | 12 mg/day moderate · 18 mg/day severe | IN | 5–10 days | Acute ischemic stroke — not cognition |
| Gusev 2018n = 110 | 6,000 mcg/day | IN | 2 × 10-day courses + 20 d gap | Post-stroke rehabilitation · BDNF/motor |
| Koroleva 1996n = 37 | 0.5 mg/kg once | IN | Single | Pain research · FDA summary |
| Polunin 2000n = Optic nerve | Not in abstract | IN drops / electrophoresis | Study-specific | Visual outcomes with background therapy |
Evidence hierarchy for research dosage
Evidence hierarchy
Russian product strongest · SC and long-term weakest
| Category | Semax evidence | Interpretation |
|---|---|---|
| U.S. approved dosing | None | No U.S. prescribing schedule |
| Russian medicinal product | Multiple indication-specific IN regimens | Strongest practical documentation |
| Human clinical evidence | 250 mcg–20 mg/day by context | Exposure documented · quality varies |
| Healthy-adult experimental | 250 mcg · 1 mg/2 d · 1.2 mg once | Acute studies · limited efficacy |
| Preclinical | 25–100 mcg/kg rodents | Mechanistic only |
| Anecdotal IN | 100–600 mcg/admin common | Low confidence |
| Anecdotal SC | 100–500 mcg/day reported | Very low · no human SC study in FDA review |
Commonly reported research protocols
Reported protocols
Russian label · fMRI single dose · online IN/SC · proposed study
- Amount
- 400–900 mcg/day total
- Frequency
- 2–3× first half of day
- Route
- IN drops
- Duration
- 3–5 days
- Evidence basis
- Product instructions
Cumulative exposure examples
Cumulative exposure
Daily and course totals — online · proposed · rehab context
Daily
400 mcg
Course total
5.60 mg
Per dose
200 mcg × 2/day
Anecdotal versus clinically studied dosing
Evidence split
Medicinal-product record vs online conventions
Medicinal-product and human study record
Indication-specific · intranasal
- Mental fatigue (0.1%)
- 400–900 mcg/day · 3–5 days
- Healthy fMRI
- 1.2 mg once
- Rehabilitation
- 6 mg/day · 2 × 10-day courses
- Moderate stroke (1%)
- 6–12 mg/day · 10 days
- Human SC dose
- None validated in FDA review
Online / community conventions
Often extends duration or uses SC without basis
- Typical per admin
- 100–600 mcg
- Frequency
- 1–2× daily · sometimes 5 on/2 off
- Duration
- 10–20 days to 8 weeks
- 0.1% vs 1% confusion
- Tenfold error risk
- Modified analogs
- Cannot assign doses to parent Semax
Preclinical research dosage
Preclinical anchors
25–100 mcg/kg rodents — mechanistic only
| Model | Dose | Route | Outcome |
|---|---|---|---|
| Rats | 50 mcg/kg | IN once | Hippocampal BDNF/TrkB · avoidance learning |
| Rats neonatal isolation | 50 mcg/kg/day | IN × P15–28 | Long-lasting behavioral effects |
| Rats MCAO | 100 mcg/kg | IP × 4 | Ischemic cortex transcriptome |
| Rats ischemia model | 25 mcg/kg/day | IN × 7 d | PGC-1α neuroprotection |
25–100 mcg/kg rodent anchors are mechanistic — not human dose by weight conversion.
Mechanism relevant to dosage
No clinically validated receptor-occupancy target. Preclinical threads: BDNF/TrkB, neurotrophin gene expression, monoaminergic effects, ischemia-related gene programs, Pro-Gly-Pro metabolites. More Semax ≠ proven more BDNF or better human outcomes.
Safety, side effects, and monitoring
Safety monitoring
Product label · nasal/CNS domains · FDA compounding note
- Product label (0.1%)
- Mild nasal irritation with prolonged use; contraindications include pregnancy, acute psychiatric states, anxiety disorders, seizure history, age limits
- Nasal
- Burning, dryness, congestion, epistaxis, smell change — examine and score in trials
- Psychiatric / sleep
- Activation, anxiety worsening, insomnia, mood elevation, mania — monitor especially with stimulants
- FDA compounding (2026)
- Proposed neither Semax free base nor acetate for 503A list — aggregation, impurities, device/formulation gaps
Dose escalation
Russian instructions divide large doses for nasal volume — not tolerance titration. Online 50→600 mcg step-up lacks controlled dose-response evidence. 5-on/2-off receptor-reset claims are unproven.
Complete proposed dose-ranging research protocol
Part A: 30 healthy adults · 5-period crossover · placebo, 200, 450, 900, 1,200 mcg single IN · 7-day washout.
Part B: 200 healthy adults · 5 days · placebo vs 400 / 900 / 1,800 mcg/day (200+200, 450+450, 900+900 at 08:00 and 13:00) during standardized cognitive-fatigue workload.
Proposed dose-ranging design
Part A crossover singles → Part B 400 / 900 / 1,800 mcg/day × 5 days
Part A — 30 healthy adults · 5-period crossover · 7-day washout
| Period | Single dose | Note |
|---|---|---|
| 1 | Placebo | Placebo |
| 2 | 200 mcg | 200 mcg single |
| 3 | 450 mcg | 450 mcg single |
| 4 | 900 mcg | 900 mcg single |
| 5 | 1200 mcg | 1.2 mg single (fMRI amount) |
Part B — 200 healthy adults · cognitive-fatigue workload · 08:00 + 13:00
| Arm | AM / PM | Daily total |
|---|---|---|
| Placebo | Placebo | Placebo |
| Low | 200 + 200 mcg | 400 mcg/day |
| Mid | 450 + 450 mcg | 900 mcg/day |
| High | 900 + 900 mcg | 1800 mcg/day |
Low arm matches Russian mental-fatigue lower bracket; high arm extends upper bracket. Requires validated metered intranasal delivery and MEHFPGP assay — not consumer droppers.
Claims versus evidence
Claim checker
Common Semax claims vs the evidence record
300–600 mcg is the proven cognitive dose
Overstated
Overlaps lower Russian daily range but no modern controlled dose-response trial for healthy cognition.
Dosage evidence ladder
Dosage evidence ladder
Russian product strongest · SC and long-term weakest
| Dosage information | Evidence | Status |
|---|---|---|
| U.S. approved dosing | None | None |
| Russian product instructions | Indication-specific IN regimens | Established for product |
| Human clinical dosing | Heterogeneous · often small/old | Moderate · context-dependent |
| Healthy-adult experimental | Acute 250 mcg–1.2 mg | Limited |
| Preclinical | 25–100 mcg/kg rodents | Mechanistic only |
| Anecdotal IN | 100–600 mcg/admin common | Low |
| Anecdotal SC / long-term | Reported online | Very low |
Bottom line
Semax dosing is well described for specific Russian indications but does not create one universal dose. 0.1% vs 1% must stay explicit. Stroke mg/day regimens are not cognitive precedents.
The highest-value next study for healthy-adult cognitive use is a placebo-controlled intranasal dose-ranging trial (400 vs 900 vs 1,800 mcg/day) with validated PK and device delivery — not extrapolation from analogs, injection, or 1% stroke labels.
50 vs 500 mcg/drop · 400–900 mcg/day fatigue label · 6–20 mg/day stroke only · SC unvalidated.
Frequently asked questions
What is the standard Semax dose?
There is no single standard. Russian instructions range from 400–900 mcg/day for short mental-fatigue courses to 12–20 mg/day for severe acute stroke, with multiple regimens between.
What is the difference between 0.1% and 1%?
1% is ten times as concentrated — approximately 50 mcg vs 500 mcg per conventional drop.
What dose is used for mental fatigue?
Russian 0.1% instructions: 400–900 mcg/day in 2–3 administrations during the first half of the day for 3–5 days.
What dose was used in healthy human research?
Reported exposures include 250 mcg once, 1 mg daily for two days, and 1.2 mg once in fMRI work.
Is 300–600 mcg the proven cognitive dose?
No. It is frequently repeated online and overlaps lower product ranges, but a controlled modern dose-response trial has not established it as optimal.
Is there a validated injectable dose?
No. FDA's 2026 review did not locate published human subcutaneous Semax administration.
Can Semax be combined with Selank at the same doses?
The combination is common commercially, but no adequate human fixed-combination trial establishes dose, safety, or synergy.
Is N-acetyl Semax dosed the same way?
No established conversion. Modified analogs are different chemical entities.
What is the maximum Semax dose?
No universal maximum. The 20 mg/day severe-stroke instruction is context-specific and must not be interpreted as a general maximum for other populations.
How long is Semax typically used?
Product record emphasizes short courses: 3–5, 7–10, or 10–14 days. Multi-month continuous use lacks adequate evidence.
References
Semax manufacturer
Russian 0.1% instruction PDFIndication-specific dosing.
RLS
Semax Russian monograph0.1% and 1% regimens.
FDA
Semax PCAC briefing documentJuly 2026 · proposed not on 503A list.
Panikratova YR et al.
Selank and Semax fMRI1.2 mg Semax once · separate groups.
Gusev EI et al.
Acute stroke Semax 199712–18 mg/day stroke context.
Gusev EI et al.
Rehabilitation Semax 20186 mg/day · two 10-day courses.
PubChem
SemaxCID 9811102.