Quick summary
Semax 4-7 is the core ACTH(4-7) tetrapeptide (Met-Glu-His-Phe) responsible for the nootropic and neuroprotective effects of Semax. It modulates melanocortin receptors and BDNF signaling but has a shorter duration than full Semax due to lacking the stabilizing Pro-Gly-Pro extension.
Overview
Semax 4-7 is the core tetrapeptide sequence Met-Glu-His-Phe, corresponding to ACTH amino acids 4–7. It represents the minimal active fragment underlying the nootropic and neuroprotective properties of Semax (ACTH(4-7)-Pro-Gly-Pro). Unlike full Semax, it lacks the C-terminal Pro-Gly-Pro extension that improves stability, resulting in a shorter-acting but more simplified pharmacological tool for studying ACTH-derived cognitive effects.
Mechanism of action
ACTH(4-7) interacts with melanocortin receptors (particularly MC4R in the brain) and modulates BDNF signaling, dopaminergic and serotonergic neurotransmission. Research suggests this tetrapeptide sequence is responsible for attention-enhancing and memory-consolidating effects attributed to ACTH analogs. It may enhance synaptic plasticity by upregulating neurotrophin expression. The Pro-Gly-Pro C-terminal extension in standard Semax primarily confers metabolic stability rather than adding distinct pharmacological activity.
Dosing protocols
| Purpose | Route | Dosage | Frequency | Notes |
|---|---|---|---|---|
| cognitive research (intranasal) | nasal | 100–600 mcg | once to twice daily |
Dosing information is for educational purposes only. Consult a qualified healthcare professional before using any peptide.
Research summary
Semax 4-7 research is largely foundational to understanding the active pharmacophore of Semax. Soviet and Russian research established that ACTH(4-7) fragments modulate learning and memory in rodent models. The full Semax molecule (with C-terminal Pro-Gly-Pro) has been more extensively studied and approved in Russia for stroke and cognitive impairment, with the 4-7 core considered the pharmacologically active portion. Limited standalone human data exist for the isolated tetrapeptide.[1][2][3][4]
Evidence grading
Each claimed benefit is graded by the strength of available evidence. Grades reflect study quality, not effect size.
Strong = multiple RCTs · Moderate = limited trials or observational · Preliminary = animal or in vitro only · Insufficient = anecdotal or no published data
Side effects
Side effects vary by individual. This is not an exhaustive list. Report unusual symptoms to a healthcare professional.
Common stacks
Peptides commonly paired with Semax 4-7 for synergistic effects.
Legal status
Semax 4-7 is not approved by the FDA and is classified as a research compound. Not listed as a controlled substance in the US but is in a legal gray zone as an unscheduled peptide research chemical.
Sourcing & access
Research compound
Semax 4-7 is classified as a research compound. Regulatory status varies by jurisdiction. Always verify current legal status and source from vendors providing third-party certificates of analysis (COA).
Frequently asked questions
Semax 4-7 is the minimal active tetrapeptide fragment (Met-Glu-His-Phe) corresponding to ACTH amino acids 4-7. It is the pharmacologically active core of the nootropic peptide Semax, without the C-terminal Pro-Gly-Pro extension that provides metabolic stability.
It interacts with melanocortin receptors (particularly MC4R) in the brain and modulates BDNF signaling, dopaminergic, and serotonergic neurotransmission. This tetrapeptide sequence is responsible for the attention-enhancing and memory-consolidating effects attributed to ACTH analogs.
Reported side effects include nasal irritation, headache, and mild fatigue. It is classified as a research compound and is not FDA-approved. Limited standalone human safety data exist for the isolated tetrapeptide.
Semax 4-7 lacks the C-terminal Pro-Gly-Pro tripeptide extension present in full Semax. This extension primarily confers metabolic stability rather than additional pharmacological activity, meaning Semax 4-7 has the same mechanism but a much shorter duration of action.
Research references
- Semax ACTH(4-7)PGP fragment and cognitive function: neurotrophin mechanismsPubMed
- Semax and its fragments in attention and cognitive task performancePubMed
- Semax peptide anxiolytic and antidepressant properties in animal modelsPubMed
- Semax effects on BDNF expression and hippocampal neuroplasticityPubMed