Peptide reference
Semax
Last reviewed · Written by the PepCycle team
Semax is a synthetic peptide based on a fragment of ACTH (amino acids 4–10) with an added stabilising sequence. It was developed in Russia, where it is a registered medicine used in neurological indications. It is unapproved in the US, EU and UK, and is most often supplied as a nasal solution rather than an injectable vial.
What Semax is
Semax is a heptapeptide derived from the 4–10 fragment of adrenocorticotropic hormone (ACTH), joined to a short Pro-Gly-Pro sequence that improves its stability. The parent fragment is known for behavioural effects without the hormonal activity of full ACTH, which is what made it an attractive starting point.
It was developed at Russian research institutes and is registered as a medicine in Russia, where it has been used in indications including stroke recovery and cognitive complaints. That registration is real but jurisdiction-specific: it does not represent an FDA or EMA assessment, and the supporting literature is largely published in Russian.
Forms and variants
Two things distinguish Semax from most compounds in this reference: the route and the variants.
| Variant | What it is | Typical form |
|---|---|---|
| Semax | The base heptapeptide | Nasal solution, sometimes lyophilised powder |
| N-Acetyl Semax amidate | Acetylated and amidated variant, often abbreviated NASA | Nasal solution or spray |
Because it is typically intranasal, the usual peptide arithmetic mostly does not apply. There is no syringe, no U-100 barrel, and often no reconstitution you performed yourself. What you record instead is the product concentration as labelled and the number of drops or sprays.
Logging a nasal peptide
A tracker built only around injections handles this badly — which is why PepCycle treats route as a property of the entry rather than assuming everything is an injection.
- Record the product concentration exactly as labelled (for example, mg per mL of solution).
- Record drops or sprays per entry, and which nostril if you rotate — the nasal analogue of site rotation.
- If you reconstituted a powder into a nasal dropper yourself, the reconstitution record still matters: mass, volume and date.
- Note the variant in the compound name, since Semax and N-Acetyl Semax are not one compound.
Status
Semax is unapproved in the US, EU and UK, and importing unapproved medicines has its own legal considerations that vary by country. Much of the supporting literature is Russian-language and predates modern trial-reporting standards, which is a real limitation when assessing evidence rather than a dismissal of it.
Frequently asked questions
Is Semax approved anywhere?
It is a registered medicine in Russia, used in neurological indications there. It is not approved in the US, EU or UK. A registration in one jurisdiction is not a substitute for assessment by another regulator.
What is the difference between Semax and N-Acetyl Semax amidate?
N-Acetyl Semax amidate is a chemically modified variant, acetylated at one end and amidated at the other, typically marketed as more stable. It is a different product from plain Semax and belongs in your log as a separate compound.
How do I log a nasal peptide when there is no syringe?
Record the labelled solution concentration, the number of drops or sprays, and the device. If you change bottles or devices, start a new vial record, because delivered volume per actuation is not standardised across devices.
Related pages
Track Semax without re-doing the maths
Enter the vial once — mass, diluent volume, lot, date — and every entry after that converts automatically between mcg, mL and syringe units, with the vial counting down as you log.
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