What Is Semax Peptide?
Semax is a heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. The first four amino acids are positions 4 to 7 of adrenocorticotropic hormone (ACTH), a region of the hormone that affects the brain but not the adrenal glands. The last three, Pro-Gly-Pro, were added to slow its breakdown by enzymes. It is usually described as an analogue of ACTH (4-10).
Semax was developed at the Institute of Molecular Genetics of the Russian Academy of Sciences, the same institute behind selank, and the two share the same Pro-Gly-Pro stabilising tail. What semax does not carry is ACTH's main job: it has no corticotropic activity, so it does not drive cortisol production. That separation of brain effects from hormonal ones is the reason it was designed.
What Does Semax Do? How Semax Works in Research
Semax is studied mainly for its effects on the brain, almost entirely in animal and cell models. The main lines of research are:
- BDNF. Studies in rats report that semax increases levels of brain-derived neurotrophic factor (BDNF) and its receptor in the hippocampus, a region central to learning and memory. BDNF is the thread running through most semax research.
- Neuroprotection. Semax has been widely studied in models of cerebral ischaemia, where research examines its effect on the damage that follows restricted blood flow to the brain.
- Gene expression. Several papers report that semax changes the expression of genes involved in inflammation, the vascular system and neurotransmission after ischaemic injury.
- Cognition. Animal studies examine its effects on attention, learning and memory tasks.
Browse the published work, with links to each paper, in our semax research library.
Semax Nasal Spray
Semax is best known in nasal form: in Russia it is registered as a medicine in the form of intranasal drops, and that is where most searches for semax nasal spray, semax drops and intranasal semax come from. Chainwell Peptide supplies semax in that format as a 10 mL nasal spray bottle holding 10mg of semax in solution, 1mg per mL, under a white pump actuator.
The spray needs no preparation: there is no powder to reconstitute and no diluent to measure, and the concentration is fixed at 1mg per mL. Keep the bottle refrigerated at 2 to 8 °C, protected from light, and follow the expiry on the label. Every spray lot is tested by an independent laboratory for identity and purity, and its lot number matches the certificate on our COA lookup page. Semax is not approved by the TGA or the US FDA, and the spray, like the vial, is supplied for research use only.
Semax Half-Life
Like most short peptides, semax is broken down quickly once in circulation; its reported half-life in blood is measured in minutes, even with the Pro-Gly-Pro tail. Research interest centres on the fact that its effects on gene expression and BDNF are reported to outlast the peptide itself. The practical point for storage is the opposite: in its lyophilized form, semax is stable, and it only becomes time-limited once reconstituted.
N-Acetyl Semax Amidate vs Semax
N-acetyl semax amidate adds an acetyl group to one end of the chain and an amide to the other, changes intended to make the peptide still more resistant to breakdown. It is a different compound from standard semax, with far less published research behind it, and it has a different molecular mass. We supply standard semax, the form used in the original Russian research and most studies since.
Semax and Selank
Semax and selank are often ordered together because they come from the same institute and share a stabilising tail, but they are studied for different things. Semax is built from an ACTH fragment and studied for cognition and neuroprotection; selank is built from tuftsin and studied for anxiety-related behaviour and immune signalling. Our selank page has a full semax vs selank comparison table. For studies that use both, order separate vials so each can be measured on its own.
Semax 10mg Vial
We supply semax as a 10mg lyophilized vial in a 3 mL clear glass vial with a rubber stopper and a teal flip-off cap, the colour we use across our nootropic research peptides. We do not stock a 5mg fill.
To reconstitute semax, add bacteriostatic water slowly down the inside wall with a U-100 insulin syringe and swirl gently until clear; do not shake. As a worked example, 2 mL in the 10mg vial gives 5mg per mL. Does semax need to be refrigerated? Once reconstituted, yes: keep it at 2 to 8 °C, protected from light, and use it within 28 days. Unopened, it keeps longest frozen at minus 20 °C. Our reconstitution guide and calculator covers other volumes.
Semax Vial or Nasal Spray?
| 10mg vial | Nasal spray | |
|---|---|---|
| Form | Lyophilized (freeze-dried) powder | Solution, 1mg per mL |
| Container | 3 mL glass vial, teal flip-off cap | 10 mL bottle, pump actuator |
| Preparation | Reconstitute before use | None |
| Concentration | Set by you | Fixed at 1mg per mL |
| Storage | Frozen long term; 2 to 8 °C once reconstituted | 2 to 8 °C, protect from light |
Our recommendation: choose the vial when your work needs semax at a concentration or in a vehicle you choose, or when you want the longest shelf life. Choose the semax nasal spray when your research design calls for the intranasal format. Researchers working with both peptides can pair it with the selank nasal spray.
Lab-Tested Semax With a COA for Every Lot
Every Chainwell Peptide semax lot is sent to an independent laboratory before release. Mass spectrometry confirms the molecular mass matches semax, around 814 g/mol, which also distinguishes it from N-acetyl semax amidate, and HPLC measures purity. A lot that does not meet specification is not sold. Check your lot on our COA lookup page.
Buy Semax in Australia
Chainwell Peptide supplies semax for sale in Australia to laboratories, universities and independent researchers, packed and dispatched from within Australia. Before you buy semax online from any supplier, check that the listing says whether it is standard semax or N-acetyl semax amidate, that the vial carries a lot number, and that the certificate for that lot is available before you pay.
- Same-day dispatch on orders paid before 3pm on a business day.
- Australia-wide delivery to Sydney, Melbourne, Brisbane, Adelaide, Perth, Hobart, Darwin and regional addresses, by standard or express post.
- PayID or bank transfer, with your order number as the payment reference.
- Tracked orders you can follow on our order tracking page.
The current price is shown at the top of this page, with GST included. See our shipping policy for delivery details.
Semax Specifications
| Compound | Semax |
|---|---|
| Class | Synthetic regulatory peptide, ACTH (4-10) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP) |
| Molecular formula | C37H51N9O10S |
| Molecular weight | Approximately 813.9 g/mol |
| Formats | 10mg lyophilized vial; 10 mL nasal spray, 10mg at 1mg per mL |
| Containers | 3 mL glass vial with teal flip-off cap; 10 mL bottle with pump actuator |
| Identity and purity | Mass spectrometry and HPLC, per lot |
| Diluent | Vial: bacteriostatic water, sold separately. Spray: none needed |
| Storage | Vial: minus 20 °C long term. Spray and reconstituted vial: 2 to 8 °C, protect from light |
| Shipping | Standard or express post, Australia-wide |
Research Use Only
Semax is not approved by the Therapeutic Goods Administration for any therapeutic use. Chainwell Peptide sells it strictly for laboratory and in vitro research. It is not for human or veterinary use, and we do not provide dosing advice. By ordering you agree to our terms and conditions and research use only statement.
Semax FAQ
What is semax?
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Semax is a synthetic seven amino acid peptide, Met-Glu-His-Phe-Pro-Gly-Pro, built from the ACTH (4-7) fragment with a Pro-Gly-Pro tail for stability. It was developed at the Russian Academy of Sciences and has no hormonal effect on the adrenal glands. Chainwell Peptide supplies it as a 10mg research vial.
What does semax do?
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In research, semax is studied for effects on the brain. Published work in animal models reports that it raises BDNF in the hippocampus, examines its role in protecting brain tissue after restricted blood flow, and studies its effects on learning and attention tasks.
Do you sell semax nasal spray?
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Yes. Chainwell Peptide supplies semax as a 10 mL nasal spray holding 10mg in solution at 1mg per mL, as well as a 10mg lyophilized vial. The spray needs no reconstitution; the vial lets you set your own concentration. Both come with a lot-matched certificate of analysis.
What is the half-life of semax?
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Semax is broken down quickly in circulation, with a reported half-life in blood measured in minutes, even with its stabilising Pro-Gly-Pro tail. In lyophilized form it is stable; once reconstituted, keep it at 2 to 8 °C and use it within 28 days.
Is N-acetyl semax amidate the same as semax?
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No. N-acetyl semax amidate adds an acetyl group and an amide to the semax chain for extra stability, making it a different compound with a different mass and far less published research. Chainwell Peptide supplies standard semax, confirmed on the certificate of analysis.
Where can I buy semax in Australia?
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You can buy semax in Australia from Chainwell Peptide as a 10mg lyophilized vial or a 10 mL nasal spray. Every lot carries a lot number matched to an independent certificate of analysis, and orders paid before 3pm on a business day ship the same day by standard or express post.
