Semax is a synthetic peptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro, an analogue of a fragment of the adrenocorticotropic hormone, ACTH(4-10), used intranasally (in the nose) as a nootropic and neuroprotective agent. In medicine form it is produced mainly as 0.1% drops (for cognitive, "nootropic" indications) and 1% (for acute neurological conditions). The approximate nootropic daily dose per the official label is about 600-900 mcg, over a course of several days. Below is how the forms are arranged, the instillation technique and dosing; an important note up front: the evidence base for Semax is mostly preclinical and Russian-language, so some of the "nootropic" claims are not confirmed by quality RCTs (randomised controlled trial). A detailed breakdown of composition and mechanism is in the Semax monograph, and for research raw material see the product page.

What Semax is and why it is given into the nose

Semax is a heptapeptide developed in the 1980s in Russia (the Institute of Molecular Genetics of the Russian Academy of Sciences together with Lomonosov Moscow State University). Its molecule combines the active ACTH(4-7) fragment (Met-Glu-His-Phe) with the C-terminal tripeptide Pro-Gly-Pro (PGP), which substantially slows enzymatic breakdown of the peptide. Thanks to this stabilisation, a single administration acts longer than the "pure" ACTH fragment.

The fundamental difference from full ACTH: Semax retains neurotrophic properties but has no hormonal activity, it does not stimulate cortisol release by the adrenal glands. The intranasal route was chosen because the peptide passes poorly through the gastrointestinal tract (it is destroyed by proteases), while the nasal mucosa gives rapid absorption and partial transport to the CNS.

Available forms: 0.1% and 1% drops

  • Semax 0.1%, a 1 mg/ml solution. One drop of ~0.05 ml contains about 50 mcg of active substance. This is the "cognitive"/nootropic form: optic-nerve diseases, asthenic states, prevention and recovery of cognitive function as prescribed by a doctor.
  • Semax 1%, a 10 mg/ml solution; one drop of ~0.05 ml contains about 500 mcg. This is the form for acute conditions (the acute period of ischaemic stroke, transient ischaemic attacks), used in larger, milligram daily doses strictly under a doctor's supervision.

Both forms are a dropper bottle for intranasal administration. This is not a spray in the classic sense: the classic registered form is precisely drops; some manufacturers offer a metered dropper, but the dose is still counted in drops.

How to apply it intranasally (technique)

Per the official label, the instillation scheme looks like this:

  1. The head is held straight or tilted slightly back.
  2. The solution is instilled at 2-3 drops into each nostril.
  3. Only 3-4 drops are "held" in a nostril at a time; if a larger single dose is needed, it is given in several steps at 10-15 minute intervals.
  4. After instillation, do not blow the nose for a few seconds so the solution does not leak out.

The therapeutic effect of a single administration, according to the label, can persist for a long time (up to ~20-24 hours), again thanks to the stabilising PGP fragment. An opened bottle is usually kept in the refrigerator and used for a limited time (per the manufacturer's label); the exact conditions and shelf life after opening are stated on the packaging of the specific product.

Dosing: how much and how long

General ranges per the label (0.1%):

  • single dose, 200-2000 mcg (about 3-30 mcg/kg);
  • daily dose, 500-5000 mcg (7-70 mcg/kg);
  • course length, usually 3-5 days, extended up to 14 days if needed.

As a nootropic / for optic-nerve diseases: a typical daily dose is 600-900 mcg (that is, roughly 2-3 drops of 0.1% into each nostril 2-3 times a day), a course of about 7-10 days. This is the most common "cognitive" regimen mentioned by official sources (the labels on apteka911, mozdocs, materials from the manufacturer "Peptogen").

Acute conditions (1%): in the acute period of ischaemic stroke, significantly higher daily doses are used, in the milligram range (a few mg per day, more in severe cases), split over several administrations. Such regimens are prescribed only by a doctor in a hospital setting; self-administration of the 1% form is inappropriate.

Important: the figures given are general reference points from the label, not a personal recommendation. The specific dose, frequency and duration are determined by a doctor, taking into account the indication, age and condition of the patient.

A short fact block

  • Sequence: Met-Glu-His-Phe-Pro-Gly-Pro (heptapeptide; ACTH4-7 fragment + Pro-Gly-Pro stabiliser).
  • Class: synthetic ACTH(4-10) analogue; nootropic/neuroprotector without hormonal (cortisol-stimulating) activity.
  • Forms: intranasal drops 0.1% (1 mg/ml) and 1% (10 mg/ml).
  • Drop: ~0.05 ml ≈ 50 mcg (0.1%) or ≈500 mcg (1%).
  • Nootropic daily dose: usually 600-900 mcg; general range 500-5000 mcg/day.
  • Course: 3-5 days, up to 14 days if needed.
  • Development: the 1980s, Russia (IMG RAS / MSU).
  • Registration as a medicine: the Russian Federation (it was on the Vital and Essential Drugs list) and Ukraine. Registration status changes, so its currency should be checked in the state register of medicines.
  • Evidence base: largely preclinical (rodents) + mostly Russian-language clinical publications; independent large RCTs are scarce.

What the evidence base says (honestly)

This is the most important section. Semax is a real peptide with decades of research behind it, but the quality and availability of the evidence are uneven:

  • The mechanism is well described in preclinical models: in rodents Semax affects the brain transcriptome, raises the expression of neurotrophins (BDNF in particular) and their receptors, and modulates the inflammatory and immune response in ischaemia. This is confirmed by peer-reviewed transcriptomic and proteomic work in rats (see "Sources").
  • Clinical data on stroke and cognitive indications exist, but mostly in Russian-language publications, often old and methodologically heterogeneous. Independent, large, multicentre RCTs indexed in international databases are scarce.
  • For healthy people (use "for focus/memory") quality placebo-controlled evidence of effectiveness is lacking; here it is correct to speak of preliminary/indirect data, not a proven nootropic effect.

In short: preclinical results or a few small studies should not be passed off as a large evidence base. Where there are no reliable RCTs, it is more honest to say so directly.

Safety, contraindications and limitations

  • Contraindications per the label usually include: hypersensitivity to the components, acute psychotic states, states with marked anxiety, pregnancy and lactation (safety has not been studied), and childhood (the forms are registered for adults).
  • Tolerability at the doses given is generally described as good; mild local irritation of the nasal mucosa is possible, especially for the 1% solution.
  • Data limitations: long-term safety with prolonged "nootropic" use in healthy people has not been studied systematically. An absence of frequent reports of side effects does not equal proven long-term safety.
  • Regulatory status differs between countries: where Semax is registered as a medicine, it is used as prescribed by a doctor and per the label; in many other jurisdictions it is not an approved drug.

If you are interested in the chemistry, sequence and mechanism in more detail, read the Semax monograph. For the Longeva research raw-material form, see the product page.