Semax 5mg · ACTH(4-7) Analog (Pro-Gly-Pro extension) · 99.0% Purity

What is Semax?

Semax is a synthetic heptapeptide analog of ACTH(4-10) with an added Pro-Gly-Pro fragment for enzymatic stability. Developed in Russia in the 1980s, it is approved there for stroke, cognitive impairment, and optic-nerve atrophy. It is one of the most-studied peptides for cognitive enhancement and motivational energy.

What is Semax used for?

Research applications include focus and working-memory enhancement, post-stroke neuroplasticity, BDNF/NGF upregulation research, and acute attention-deficit protocols. Often stacked with Selank for combined dopaminergic + cognitive support, with DSIP for cycled CNS protocols, or with MOTS-c for energy-research stacks.

How does it work?

Heptapeptide analog of ACTH(4-10); increases BDNF and NGF expression; modulates dopamine, serotonin, and acetylcholine. Read our complete research hub for the full literature review, or jump to our best peptides for cognitive article for comparator molecules.

Why this listing?

Semax produces robust increases in BDNF and NGF expression — neurotrophic effects that distinguish it from classical stimulants. Helix Peptides' SMX-2604-F batch tested 99.0% pure. Available as both lyophilized powder and pre-mixed intranasal solution.

How Peptide.best sources and verifies Semax

Every Semax listing on Peptide.best comes from a verified vendor that has passed our onboarding audit — GMP-licensed manufacturing facility, documented chain of custody, third-party Janoshik Analytical testing on every batch, and a published Certificate of Analysis. Helix Peptides (the seller on this listing) currently maintains a 4.7-star average across all their products. Compare the five live offers on the right side of this page — Peptide.best forces vendors to compete on price and purity for the same SKU, so you always see the best current deal at the top, with the COA-verified purity, shipping speed, and seller rating side-by-side. Looking for alternatives in the same cognitive space? Selank and the other peptides listed under our Cognitive category are the most commonly compared alternatives.

Commonly stacked with

Selank · DSIP · MOTS-c · Epitalon. See the peptide stacks page for full protocol writeups.

Compliance notice

Semax has not been evaluated by the FDA for any indication. All statements on this page are based on published research and are not medical claims. Some products may be sold for research purposes only as marked. Consult a licensed healthcare provider before use. See our full disclaimer.

Research literature

Semax has been the subject of growing peer-reviewed and preclinical research across the cognitive domain. The current PubMed index returns several hundred citations spanning mechanism, dose-response, and adverse-event reporting.

Key references commonly cited in Semax research:

• Mechanism papers covering heptapeptide analog of acth(4-10); increases bdnf and ngf expression; modulates dopamine, serotonin, and acetylcholine.
• Dose-response work in rodent models (most studied species)
• Comparator-molecule trials vs. Selank and other peptides in the same class
• Safety / pharmacovigilance datasets where available

For a full reference list, see the Peptide.best Research Hub or the dedicated Cognitive pillar article.

Standard research dosing

Standard intranasal: 250–600 mcg per nostril, 1–3x daily. Acute cognitive protocols: 600 mcg pre-task. Most clinical Russian protocols use 7–14 day cycles.

Reconstitution

This product ships as liquid nasal spray or lyophilized powder. Reconstitute with Saline or bact water for stable refrigerated storage. Once reconstituted, use within 30 days; keep at 2–8°C.

Protocol notes

For full protocols and stacking guidance, see our peptide dosing guides. Always start at the low end of the published range and titrate based on individual response. Half-life (~5-15 min; CNS effects 6-24 hours) determines dosing frequency.

Reported side effects

Generally well-tolerated — occasional transient mood lift bordering on stimulation, mild nasal irritation, rare headache. No reports of dependence.

Contraindications

Do not use during pregnancy or lactation. Do not combine with other peptides without reviewing pharmacology. Consult a licensed healthcare provider before beginning any peptide research protocol. Discontinue immediately if any adverse reaction occurs and contact your provider.

Drug interactions

Limited interaction data exists for most research peptides. Be especially cautious when combining with prescription medications affecting the same physiological pathway as Semax (cognitive pathway).

Certificate of Analysis

Every batch of Semax sold on Peptide.best ships with a third-party Certificate of Analysis (COA) from Janoshik Analytical — the most-cited independent peptide testing lab in the research community.

Current batch testing summary

• Batch ID: SMX-2604-F
• Test date: 04/14/2026
• Peptide content (HPLC): 99.0%
• Mass-spec identity: Confirmed (target mass match)
• Endotoxin (LAL): Below detection limit
• Residual solvents: Within USP <467> limits

Download full COA PDF

For our overall testing process and chain-of-custody details, see Trust & Safety.

Q: Is Semax legal to purchase?

A: Semax is sold on Peptide.best for research purposes where applicable. Legal status varies by jurisdiction. See our disclaimer for full details.

Q: How long until I see effects?

A: Timing depends on protocol, dose, and individual response. Most users report observable changes within 2–6 weeks of consistent dosing per the standard research protocols. See the Dosing & Protocol tab.

Q: Can I stack Semax with other peptides?

A: Yes — see commonly stacked peptides in the Overview tab, or browse our peptide stacks page for full protocol writeups.

Q: Why is the price lower than pharmacy retail or other research sites?

A: Peptide.best aggregates verified vendors and forces them to compete in a single checkout. Vendors save on customer-acquisition cost; the savings pass to you. Every batch is still 3rd-party COA tested.

About Helix Peptides

Helix Peptides is one of the six verified vendor partners on Peptide.best. They maintain a 4.7-star average rating across all products and submit every batch to third-party HPLC analysis before it ships.

All Helix Peptides products on Peptide.best ship from a GMP-licensed contract manufacturing facility and are tested by Janoshik Analytical. Cold-chain shipping is included on temperature-sensitive products.