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Semax7 residuesMEHFPGPEach bubble = one amino acid. Size = residue mass. Color = chemical class.Also known as: ACTH(4-10)PGP, Semax peptide
A single dose triples BDNF mRNA in the rat hippocampus within hours (Dolotov et al.)[1]. Semax (ACTH 4-10 analog, Met-Glu-His-Phe-Pro-Gly-Pro) is a synthetic heptapeptide approved in Russia for stroke recovery and cognitive disorders since the 1990s. No placebo-controlled randomized trials exist in healthy adults. The cognitive effects last 1 to 3 weeks after you stop dosing, which is the rationale behind short 10 to 20 day cycles. Users chasing sharper focus, better working memory, and sustained neuroplasticity without long-term daily commitment tend to reach for this one over racetams and stimulants.
226 PubMed citations and a prescription approval in Russia. That track record separates Semax (Met-Glu-His-Phe-Pro-Gly-Pro, ACTH 4-10 analog) from most peptides in the nootropic category. The mechanism is centered on BDNF. Dolotov and colleagues confirmed that a single Semax injection at 50 mcg/kg produced a 3-fold increase in BDNF mRNA and a 1.4-fold increase in BDNF protein in the rat hippocampus [1]. A separate group showed binding-specific increases in BDNF protein in the basal forebrain [2]. Beyond neurotrophins, Semax activates dopaminergic and serotonergic systems without touching cortisol, unlike its parent molecule ACTH. In practice, the community doses 300 to 600 mcg intranasally each morning for 10 to 14 days. Thousands of user reports across r/Peptides, r/nootropics, and Longecity describe improved focus, verbal fluency, and working memory starting within the first few days. The Selank stack (300 mcg of each, intranasal AM) is the most popular combination, adding anxiolytic balance to the dopaminergic stimulation. Lebedeva and colleagues tracked 110 stroke patients on Semax and confirmed increased plasma BDNF. A 2025 study in transgenic Alzheimer's mice showed reduced amyloid plaques [3]. Another 2025 paper in the British Journal of Pharmacology identified a new mu-opioid receptor mechanism for spinal cord injury recovery [4]. The science is expanding, but it still leans heavily on animal models and small Russian clinical samples. No placebo-controlled RCT has been run in healthy adults at any dose.
Semax is a synthetic analog of ACTH(4-10) with a Pro-Gly-Pro C-terminal extension. It binds melanocortin receptors MC3R and MC4R in the brain without activating adrenal cortisol production. That selectivity is what separates it from full-length ACTH. The primary action runs through BDNF upregulation. Dolotov's group showed that 50 mcg/kg of Semax produced a 3-fold increase in exon III BDNF mRNA and a 1.4-fold increase in BDNF protein in the hippocampus [1]. TrkB receptor phosphorylation jumped 1.6-fold in the same study. Grigoriev and colleagues confirmed Semax raised NGF levels in the basal forebrain through a separate pathway [2]. The neurotrophin response begins within hours and accumulates across a 10 to 20 day cycle. The downstream signaling is broad. Semax modulates dopamine and serotonin turnover in the striatum and prefrontal cortex [5]. A genome-wide analysis of Semax in rat focal ischemia identified changes across immune, vascular, and neuroplasticity gene networks [6]. In 2025, a British Journal of Pharmacology paper revealed a previously unknown mu-opioid receptor and FTO deubiquitination mechanism relevant to spinal cord injury recovery [4]. Plasma half-life is only 2 to 3 minutes intravenously. The functional duration, though, runs 20 to 24 hours. That disconnect comes from the BDNF cascade itself; once BDNF and TrkB signaling are triggered, the downstream neuroplasticity changes continue long after the peptide clears the blood.
BDNF upregulation and neuroprotection are well-supported in rodent and cell models. Human data is limited to small Russian clinical trials in stroke and cognitive disorder patients; no placebo-controlled RCTs in healthy adults exist. 2025 studies extend preclinical evidence to Alzheimer's transgenic models and spinal cord injury via a newly identified μ-opioid receptor pathway.
Dolotov et al. 2006 (PMID 16996037): Semax regulates BDNF and TrkB in rat hippocampus; Lebedeva et al.: 110 stroke patients showed increased plasma BDNF with Semax; PMID 41479572 (2025): Semax reduced amyloid plaques in transgenic AD mice; PMID 40692165 (2025, British J Pharmacology): μ-opioid receptor / FTO deubiquitination mechanism for SCI recovery
Majority of evidence from rodent and cell models. Human trials conducted in Russia (stroke, cognitive disorders) with limited published methodological detail. No placebo-controlled RCTs in healthy adults at any dose. Mechanism of prolonged functional duration (20-24h BDNF cascade from 2-3 min plasma t½) is documented but not fully characterized at human doses.
Widely regarded as one of the most reliable nootropic peptides. Strong consensus on focus, working memory, and mental clarity. Short cycles with persistent post-cycle benefits are a distinguishing feature.
Mechanism aligns: BDNF upregulation and dopamine/serotonin modulation explain reported cognitive effects. Science focused on stroke/neurological injury; community applies it to healthy adult enhancement with no direct RCT support for that population. Doses broadly consistent (animal ~100-500 mcg/kg; community 300-600 mcg ≈ 4-8 mcg/kg for 70 kg). Both agree on short cycles (10-20 days) and morning-only timing.
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 200mcg | Daily |
| Moderate | 500mcg | Daily |
| Aggressive | 1mg | Daily |
Reconstitution math for the standard setup: 5 mg vial plus 2 mL bacteriostatic water gives you 2500 mcg/mL. On a U-100 insulin syringe, 200 mcg is 8 IU, 300 mcg is 12 IU, 400 mcg is 16 IU, 500 mcg is 20 IU. For pre-made nasal spray (common at 30 mg/10 mL = 3000 mcg/mL), verify the mcg-per-spray with your vendor before dosing. Spray calibration varies between atomizers. Morning only. Nothing after noon. The dopaminergic tail will disrupt your sleep if you dose late. This is the single most common correctable complaint in community reports. Start at 200 mcg. Assess tolerance for 3 days before moving to 300 mcg. The response curve is clear in the community data; 300 to 500 mcg is where most users settle. If you feel nothing by day 5, check three things. Is the vial refrigerated and under 21 days post-reconstitution? Is the reconstitution volume correct (a dilution error is the most common source problem)? Did you actually dose in the morning on an empty stomach? Advancing to 400 mcg is reasonable after ruling those out. Stacking with Selank 300 mcg intranasal takes the edge off for users sensitive to the dopaminergic stimulation. That combination is the community default for good reason.
Short 10–20 day cycles match Russian approved clinical protocols and are reinforced by community observation of diminishing returns beyond ~day 14. Proposed mechanism: adaptation of melanocortin receptor signaling and BDNF-TrkB cascade normalization following peak upregulation with continuous agonism. Dopaminergic tolerance may also contribute. No withdrawal syndrome or dependency reported; cycling preserves efficacy, not safety.
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Expected: Improved focus, mental clarity, and working memory by days 2-4. Verbal fluency and learning speed improvements most notable in week 2.
Monitor: Monitor for sleep disruption, nasal irritation, and anxiety. If no effect by day 5, verify storage and reconstitution volume.
Add 2 mL of bacteriostatic water to a 5 mg Semax vial. This gives you 2500 mcg/mL. Swirl gently, do not shake. Let the powder dissolve fully before drawing.
For subcutaneous injection, use a 29 to 31 gauge insulin syringe (U-100). 200 mcg equals 8 IU. 300 mcg equals 12 IU. 500 mcg equals 20 IU. For intranasal, transfer the reconstituted solution to a calibrated nasal atomizer or use a pre-made spray.
Subcutaneous route: clean the injection site (abdomen or thigh) with an alcohol swab. Pinch the skin and insert the needle at a 45-degree angle. Inject slowly and withdraw. Rotate injection sites between doses. Onset is approximately 30 minutes.
Tilt your head slightly forward. Insert the spray tip into one nostril, close the other, press once and inhale gently. For doses above 200 mcg, split across both nostrils with a 5-minute pause between sides. Onset is approximately 15 minutes.
Dose in the morning, before 10 AM. Do not dose after noon. The dopaminergic alerting effect lasts 20 to 24 hours at the functional level.
Refrigerate the reconstituted vial at 2 to 8 degrees C. Use within 21 days. Keep unreconstituted lyophilized powder refrigerated for long-term storage.
Typical 300–600 mcg/day in 1–2 administrations; onset ~15 min. No formal bioequivalence data vs subQ.
Convenient: no injection required. Commercial research-grade nasal sprays available. Requires sterile, pH-buffered formulation. Nasal dryness and burning common in first week.
Typical 300–800 mcg/day as single AM injection; onset ~30 min. Bioavailability vs intranasal not formally quantified.
Standard insulin syringe technique. Use abdomen or thigh. Preferred when nasal irritation is an issue or when precision dosing is required.
Plasma t½ ~2–3 min IV; clinically lower doses effective. Community protocols do not use IV.
Not recommended outside clinical settings. Context only: this is the route used in PK studies that established the 2-3 min plasma half-life.
Most popular Semax stack. Semax provides BDNF-driven focus and dopaminergic stimulation; Selank adds GABA/serotonin anxiolysis. Combined effect: cognitive enhancement without the edge, anxiety, or irritability that higher-dose Semax alone can produce. Pre-mixed nasal sprays commercially available.
Semax 300 mcg + Selank 300 mcg intranasal AM; cycle together 10–14 days on / 7 days off
Dual neurotrophic approach: Semax drives BDNF; Noopept promotes NGF and synaptic plasticity. Noopept accumulates over days of use while Semax provides acute focus enhancement.
Semax 300 mcg AM + Noopept 10–20 mg sublingual; lower doses of each to avoid overstimulation
Neurological recovery and brain fog contexts. BPC-157 supports neurotransmitter system repair; Semax drives BDNF and neuroplasticity. Used in post-concussion and TBI recovery protocols.
BPC-157 250–500 mcg AM + Semax 300 mcg AM; 4-week cycles
Bromantane provides dopaminergic/DAT upregulation; Semax handles BDNF and focus. Discussed as an acute cognitive performance ("exam stack") in nootropics communities.
Semax 300 mcg + Bromantane 50–100 mg oral; AM dosing only
Semax modulates serotonin systems; additive serotonergic effects possible. Monitor for serotonergic symptoms; dose adjustment of SSRI/SNRI may be needed.
Semax increases dopamine turnover; additive dopaminergic stimulation may cause dysregulation, anxiety, or cardiovascular effects.
Semax is an ACTH analog with melanocortin receptor activity; potential additive effects through shared MC receptor pathways. Combination unstudied.
Pricing updated 2026-04-09
Sleep disruption is the most consistently reported problem, and it is almost always a timing error. Semax increases dopamine turnover. Dosing after noon delays sleep onset for hours. Restricting administration to before 10 AM resolves the issue for most users. Even a 2 PM dose can wreck that night's sleep architecture. Anxiety and irritability rank second. The effect is dose-dependent. At 600 mcg per day and above, community reports of agitation, frustration with interruptions, and generalized anxiety increase sharply. Users with pre-existing anxiety disorders face the highest risk. Reducing the dose by 50% typically resolves the issue within 1 to 2 days. Stacking with Selank 300 mcg mitigates anxiety for most users; that combination is the most popular community protocol for exactly this reason. Nasal irritation affects intranasal users during the first week. Mild burning, tingling, and dryness at the mucosal surface are common and generally self-limiting. A saline rinse between doses helps. For persistent irritation, switching to subcutaneous injection eliminates the local effect entirely. Afternoon fatigue and a "comedown" feeling appear at doses of 600 mcg per day and higher. Splitting the dose into 2 administrations (morning and before 1 PM) or reducing to 300 to 400 mcg often solves this. Emotional blunting or mental flatness is reported with sustained use above 600 mcg per day beyond day 14. A minority of users running extended high-dose cycles also report reduced libido. Both effects resolve after stopping. Hair thinning has been described at very high doses over long periods. The reports are rare and uniformly described as reversible. Melanocortin receptor (MC4R) activation is the speculated mechanism. Human safety data is limited. The published literature comes from Russian clinical trials in stroke and cognitive disorder patients, not healthy adult nootropic users. No formal adverse event reporting exists for the community dosing context. Contraindications: pregnancy or breastfeeding (no safety data), known hypersensitivity to ACTH-derived peptides, active intracranial hypertension, history of seizure disorders (limited data, use with caution), and children under 18 without physician supervision. SSRIs and SNRIs require monitoring because Semax modulates serotonin systems; additive serotonergic effects are possible. Dopaminergic drugs (L-DOPA, dopamine agonists) carry additive stimulation risk; dose adjustment may be needed. Stop use and consult a physician if anxiety persists despite morning-only dosing at 300 mcg or below, if sleep disruption does not resolve with timing changes, or if blood pressure exceeds 130/80 mmHg.
Verify Semax dosing and safety with a second opinion
Semax is one of the most established research peptides with multiple long-running vendors and consistent community outcomes. However, it exists entirely in the unregulated research chemical market. Nasal spray formulations carry additional sterility and stability concerns that lyophilized powder does not. Removed from Category 2 on April 15, 2026. PCAC review begins July 2026; compounded pharmacy options with GMP-level controls may follow.
| Test | When | Target |
|---|---|---|
| Sleep quality (subjective: diary or wearable) | Throughout cycle, especially first week | — |
| Mood and anxiety (subjective: daily self-assessment) | Weekly during cycle; after any dose change | — |
| Blood pressure | Start of each cycle; if neurological symptoms appear | <130/80 mmHg; no Semax-specific hypertension threshold established |
Dopaminergic alerting effect can disrupt sleep architecture with late dosing; most common reason to adjust timing or reduce dose
Dose-dependent anxiety and irritability are the most common reasons to reduce or discontinue; important to track early to avoid accumulating dysphoria
Precautionary given neurovascular and BDNF-related effects. No documented hypertensive effect in published literature, but data at community doses in healthy adults is limited.
Subtle improvements in mental clarity and focus. BDNF upregulation begins within hours of first dose. Some users notice improved attention span on day one.
More consistent cognitive effects. Enhanced verbal fluency and working memory become apparent. Serotonin and dopamine modulation stabilizes.
Peak cognitive benefits. Noticeable improvements in learning speed, memory retention, and mental stamina. BDNF and TrkB receptor upregulation well-established.
Full therapeutic window. Neuroprotective effects accumulate. Many users report sustained focus and reduced mental fatigue throughout the day.
Cognitive benefits often persist for weeks after stopping due to lasting BDNF elevation and neuroplasticity changes. Typical rest period is 1-2 weeks before next cycle.
Days 1 to 3, onset. BDNF upregulation begins within hours of the first dose (Dolotov et al.)[1]. Dopamine and serotonin turnover modulation starts immediately. Community users typically notice subtle improvements in mental clarity and attention span within the first day or two. Some describe a mild stimulatory quality distinct from caffeine. Nasal tingling or light burning is normal for intranasal users during the first week; mild restlessness can occur if timing runs too late in the day. Days 4 to 7, building effect. The BDNF elevation becomes sustained. TrkB receptor upregulation consolidates. Focus and verbal fluency settle into a more consistent and reliable pattern. Working memory improvements become apparent during this window. Occasional afternoon fatigue may appear at doses of 600 mcg per day and above; some users describe increased frustration with distractions during peak effect hours. Days 8 to 14, peak window. Maximum BDNF and TrkB receptor engagement based on animal kinetics. This is the phase most community users describe as the best cognitive performance of the cycle. Learning speed, memory retention, and mental stamina all peak. The 10 to 14 day Russian clinical protocol was designed around this window. Emotional blunting or mental flatness can appear at sustained doses above 600 mcg per day; libido changes occasionally surface in a minority of extended-cycle users. Days 15 to 20, extended phase. Russian approved protocols extend to 20 days. Most community users cycle off at day 14 and report diminishing incremental returns beyond that point. Irritability can increase during this extended window. If the boost feels weaker without any change in dose or timing, receptor adaptation is the likely explanation. Post-cycle, 1 to 3 weeks off. BDNF elevation and TrkB-driven neuroplasticity changes persist after you stop dosing. Community users consistently report that focus and mood stay raised for 1 to 3 weeks after the last administration. The return to baseline is gradual. This persistent benefit is the primary reason cycling protocols exist; short active phases produce lasting cognitive returns without requiring continuous dosing.
BDNF upregulation begins within hours of first dose (Dolotov et al., PMID 16996037). Dopamine and serotonin turnover modulation begins immediately. Neurotrophin gene expression changes detectable in animal models within 1-2 hours of administration.
Subtle improvements in mental clarity and focus, sometimes on day one. Increased attention span and task engagement. Mild stimulating quality distinct from caffeine.
Sustained BDNF elevation; TrkB receptor upregulation consolidating. Serotonin and dopamine modulation stabilizes at consistent daily dose.
More consistent and reliable cognitive enhancement. Enhanced verbal fluency and working memory become more apparent. Focus is more sustained throughout the morning.
Maximum BDNF and TrkB receptor engagement based on animal kinetics. Peak neuroplasticity signaling window; aligns with Russian approved 10–20 day clinical cycle design.
Best cognitive performance of the cycle. Noticeable improvements in learning speed, memory retention, and mental stamina. Most users describe this as the optimal phase.
Russian approved protocols run to 20 days. Neuroplasticity accumulation continues but rate of additional benefit likely decreasing.
Most users cycle off at day 14. Those extending to day 20 report diminishing incremental returns after ~day 14. Extended use occasionally associated with increased irritability.
BDNF elevation and TrkB cascade-driven neuroplasticity changes may persist weeks post-administration: the mechanistic rationale for short-cycle protocols producing lasting effects.
Cognitive benefits commonly persist 1–3 weeks after stopping: widely cited as a distinguishing feature of Semax vs other nootropics. Mood and focus remain elevated in the early rest period.
Source: Plasma t½ ~2-3 min (IV); functional duration 20-24h due to BDNF cascade (Dolotov et al. 2006, PMID 16996037)
Loading the interactive decay curve.
Semax holds marketing authorization in Russia and Ukraine as a prescription drug for stroke recovery, cognitive disorders, and peptic ulcers. It has no FDA approval and no active IND application in any Western jurisdiction. Semax was on the FDA Category 2 bulk drug substance list until April 15, 2026, when HHS removed it along with 11 other peptides. PCAC review begins July 2026. Compounding pharmacy access is not yet available. Until compounding becomes available, it is sourced from research chemical vendors labeled for in-vitro research use. WADA status is uncertain. Semax is an ACTH analog with melanocortin receptor activity. Athletes subject to drug testing should treat it as a risk and consult their sport's anti-doping authority. This content is for informational and educational purposes only. It does not constitute medical advice. Consult a licensed healthcare provider before using any research compound.
Peptide Schedule Research TeamReviewed Apr 20269 Citations
