What Is Semax? The Molecule and the Vial

The molecule is synthetic. It is built to correspond to a fragment of adrenocorticotropic hormone with a short additional tail, which is why descriptions call it an ACTH derivative rather than a hormone. That relationship explains where the design came from. It does not, on its own, tell a reader what the compound does, and no sequence or molecular weight is asserted here because neither is needed for the maths and neither has been verified for this page.

Two facts about its status matter more than the chemistry. Semax has a real regulatory and clinical history in Russia, where it is used medically. It holds no authorisation from the FDA, the EMA or the MHRA, and there are no registered interventional trials for it on ClinicalTrials.gov, so no trial identifier appears on this page. Both halves of that are true at once, and dropping either one produces a misleading summary.

The Western market supplies this compound as a lyophilised powder in a small sealed vial, and as a nasal spray in a bottle with a metering pump. Buyers frequently treat those as interchangeable descriptions of one product. They are not interchangeable at the level that decides amounts.

Every container ends at the same place: a mass leaves it. Getting there takes three quantities in both cases. A labelled mass sits in a liquid volume, and the ratio of those two is a concentration. A device then removes a fixed volume. Delivered mass is concentration multiplied by removed volume.

What differs is who controls each input. With a vial, the buyer chooses the liquid volume and reads the removed volume off a printed barrel. With a spray, a manufacturer fixed the liquid volume before shipping, and the removed volume belongs to a pump that gives no feedback at all.

Take a bottle stated to hold 3 mL of solution containing 3 mg in total. Concentration is 3 divided by 3, which is 1 mg per mL. That much is arithmetic on two printed numbers.

The next step is not. Mass per actuation is concentration multiplied by the volume the pump releases, and that volume is a hardware specification rather than something observable in a bathroom. Treat it as an assumed input. Assume a pump rated at 0.1 mL. One actuation then carries 1 multiplied by 0.1, which is 0.1 mg, or 100 mcg. Swap in a pump rated 0.05 mL and the same bottle delivers 50 mcg per stroke, with no visible difference between the two.

Yield follows from the same numbers, and it is where the spray loses material the vial does not. Nominal actuations are 3 divided by 0.1, which is 30. Priming costs some of those: assume three strokes to bring liquid up the tube, which is 0.3 mL, or 300 mcg gone before the first delivered stroke. Assume a further 0.25 mL that the dip tube cannot reach at the bottom, which is another 250 mcg. Usable volume is 3 minus 0.3 minus 0.25, which is 2.45 mL, giving 24 full actuations rather than 30.

That is 2.4 mg delivered from a 3 mg label, with 0.6 mg unrecoverable in a container the buyer cannot inspect.

The vial arrives dry and has no concentration until bacteriostatic water is added. A 10 mg vial with 2 mL gives 10 divided by 2, which is 5 mg per mL. The same vial with 5 mL gives 2 mg per mL, and with 1 mL gives 10 mg per mL. The powder is identical in all three cases.

A U-100 insulin syringe holds 1 mL across 100 graduations, so one unit is 0.01 mL. At 5 mg per mL, 10 units are 0.1 mL and hold 5 multiplied by 0.1, which is 0.5 mg, or 500 mcg. Two units are 0.02 mL and hold 100 mcg.

Run it backwards and the fill volume shows its effect on readability. For 300 mcg at 5 mg per mL, volume is 0.3 divided by 5, which is 0.06 mL, or 6 units. At 2 mg per mL the same target is 0.15 mL, or 15 units, which is easier to read accurately. At 10 mg per mL it is 3 units, where a small misjudgement of the plunger position is a large fraction of the intended mass.

The pattern in that column pair is the whole point. The vial moves the uncertainty to a number the buyer writes down. The spray moves it to a number a manufacturer knows and the buyer usually does not.

Russian clinical use is real, and the material used there is a manufactured medicine produced to a specification and dispensed under supervision. That record cannot be inspected by a Western reader in the way a registration dossier submitted to the FDA or the EMA can. The literature exists in a system with different publication and review conventions, and much of it is not retrievable in the databases most readers can reach.

Calling that record nonexistent is wrong. Treating it as equivalent to a Western registration file is also wrong. The specific problem is transferability: even where the Russian evidence is sound, it describes a pharmaceutical product, not a research chemical vial reconstituted at a kitchen table, and the two share a name rather than a manufacturing standard.

Animal work in rats and mice exists and reports amounts scaled to animal body weight. Those numbers do not convert to a person by any operation performed on this page.

Nothing above produces a figure for a human being, and the omission is deliberate rather than cautious. Division moves between mass, volume and graduations. It has no access to absorption across a nasal membrane, to clearance, to the difference between a route and a dose, or to any safety margin. Handed a set of inputs, it will return a confident number in either direction, which is exactly why that number must not be presented as a recommendation.

The honest summary of the definition is short. The compound is well defined chemically, poorly documented in the sources most readers can check, approved in one jurisdiction, and sold elsewhere in two containers whose arithmetic has almost nothing in common.