Semax: an ACTH fragment with no hormonal activity, and a research base in one country

A fragment of ACTH with the hormonal part removed, approved and used clinically in Russia for decades, and almost entirely absent from Western literature. Both of those facts are load bearing.

What it is derived from, and what was taken out

Established clinical use Adrenocorticotropic hormone has effects on learning and attention that are separable from its hormonal role. Semax is the ACTH(4-7) fragment with a proline-glycine-proline tail added for stability, and the important consequence of using a fragment is that it has no corticotropic activity: it does not stimulate the adrenal gland and does not raise cortisol. The neurological activity was kept and the hormone was discarded.

Animal-only or theoretical The mechanism most often cited is upregulation of brain-derived neurotrophic factor and nerve growth factor, along with effects on dopaminergic and serotonergic transmission and on the balance of neurotrophin expression after ischaemic injury. The animal and cell work supporting that is real and reasonably extensive; whether intranasal administration in a healthy person produces a meaningful central concentration is a separate question that is much less well answered.

The app records no half-life for it, and that is not an oversight — no characterisation has been published, which is why the fact box above carries no pharmacokinetic rows.

Approved somewhere, unstudied here

Off-label or community practice Semax is an approved medicine in Russia, used for ischaemic stroke, transient ischaemic attack, cognitive impairment and optic nerve conditions, with a clinical history spanning decades and a safety record that appears good. That is substantially more than most compounds in this reference can claim.

What does not exist is independent Western replication. There is no published randomised controlled trial of semax outside the research tradition that developed it, and the approval rests on a body of work that has largely not been examined by investigators with no connection to it. That is not an accusation of anything — it is the same criticism that applies to any finding concentrated in one research lineage, and it is why this site places it with the research compounds rather than the approved ones.

The practical position for a reader outside Russia is that they cannot obtain the approved product, so what is available is a research-supply preparation. Identity and purity rest with whoever made it, and this site names no vendor or testing service.

What people actually report, and what to watch

The reported effects are stimulant-like — alertness, drive, verbal fluency — and the reported problems are the mirror image: anxiety, irritability and disturbed sleep at higher doses or later in the day. Vivid dreams turn up frequently in reports. Intranasal irritation is the local effect. None of that is surprising for something acting on catecholamine transmission, and none of it has been quantified in a controlled setting outside its country of origin.

There is no bloodwork to follow. The app records none, and that is honest: nothing on a routine panel reflects this. Assessment is subjective, which makes a dated written record of dose, timing and effect the only evidence anyone will have — and makes it easy to attribute to the peptide a good week that had other causes.

Anyone taking psychiatric medication, or with an anxiety or mood disorder, should be having this conversation with the clinician managing that rather than working it out alone. A compound reported to shift dopaminergic and serotonergic transmission is not a neutral addition to that picture.

The dosing rows the app records

Off-label or community practice Reproduced from the app’s reference so you can see what it holds, not as a recommendation. Which row applies to a particular person, if any, is a clinical decision this page does not make — and rows describing supraphysiological or post-cycle use are filtered out before this table is built, so what you see here is a subset.

What the app monitors alongside it

The panel below is the app’s own monitoring note for Semax, verbatim. None of the analytes it names has a page here yet.

Drawbacks and risks the app records

From the app’s own entry. The stimulation items and the sourcing item are the two that come up most in practice.

• Limited Western RCT data
• Intranasal administration only for CNS effects
• Anxiety or stimulant-like effect in some users
• Short half-life
• Not FDA approved
• Sourcing quality control varies
• Stimulating — can cause anxiety at high doses
• Vivid dreams reported
• Intranasal irritation
• Source quality variable

Questions people actually ask

Does it raise cortisol like ACTH?

No. The fragment used excludes the corticotropic region, which is the point of using a fragment rather than the hormone. Adrenal stimulation is not part of its profile.

Intranasal or injected?

The clinical use it is approved for is intranasal, and the app records both routes. Whether intranasal delivery produces a meaningful central concentration is the least well answered question about this compound.

Why is there no half-life in the fact box?

Because none has been published, so the app holds none. Any duration figure quoted elsewhere for this peptide is not coming from a characterisation study.

How does it compare to selank?

Same research tradition, same country of approval, different peptide and a different reported profile — selank is described as anxiolytic where semax is described as stimulating. Both carry the same replication gap.

Where the load-bearing numbers come from

Named rather than linked. Publisher URLs move, and a citation that resolves to a 404 two years from now is worse than one you can search for by name — every entry below is findable from the title and year alone.