What Is Selank? The Molecule and the Vial

A definition describes a molecule. A container describes an object with a printed mass, a liquid volume and a device attached to it, and the object is what anyone actually holds.

The chain is the same in both formats. A labelled mass sits in a liquid volume, which fixes a concentration in mg per mL. A device removes a fixed volume. The mass delivered is concentration multiplied by that volume. What changes between formats is who supplies each input.

For the vial: concentration is labelled mass divided by added volume. A 5 mg vial with 2 mL of bacteriostatic water gives 5 divided by 2, which is 2.5 mg per mL. A U-100 insulin syringe fills 1 mL at 100 units, so one unit is 0.01 mL. Ten units are 0.1 mL, and at 2.5 mg per mL that draw holds 2.5 times 0.1, which is 0.25 mg, or 250 mcg.

For the spray: a 5 mg bottle filled to 5 mL is 5 divided by 5, or 1 mg per mL. With a pump the manufacturer states delivers 0.1 mL per stroke, one actuation carries 1 times 0.1, which is 0.1 mg, or 100 mcg. The same bottle with a 0.05 mL pump carries 50 mcg per actuation.

Yield follows from either. Labelled mass divided by mass per event gives the count: 5 divided by 0.25 is 20 withdrawals from the vial above; 5 divided by 0.1 is 50 nominal actuations from the bottle, minus the strokes lost to priming a new pump and the liquid the dip tube cannot reach.

Cost per mg is price divided by labelled mass, which is the one comparison that crosses formats. On assumed figures, a 5 mg vial at 45 currency units is 9 per mg and a pre-filled 5 mg spray at 60 is 12 per mg. The spray costs more per mg and includes hardware; whether that is worth it is a decision, but it should be a knowing one.

One consequence of that spread is worth spelling out, because it explains most disagreements between two people describing the same purchase. The vial above delivers 250 mcg per event and the bottle delivers 100 mcg, from identical labels. Someone comparing their experience with a friend's, both saying "5 mg of Selank", are describing events that differ by a factor of two and a half. Neither of them said anything false, and neither of them mentioned the number that would have shown the gap.

The clinical work in humans comes from Russia, where the compound is registered as a medicine and has been studied mainly as an anxiolytic. That literature is real, it was produced under a regulator's system, and dismissing it as nonexistent is simply wrong.

Alongside it there is animal work in rats and mice, which reports amounts per kilogram of animal body weight under defined routes and models. Those are findings about rodents, and they do not convert into human figures by multiplication.

What does not exist is a genuine registered Western trial. There is none to cite, which is why no trial identifier appears anywhere on this page. A search of a Western registry by name returns records that match the text somewhere in a study description and turn out to be studies of unrelated interventions, so a hit count is not a trial count.

Both halves of the regulatory picture have to be stated together, because each half on its own is misleading.

Registration in Russia means a manufactured product went through a national review process and is used clinically there. That is a substantially stronger position than a compound with no regulatory standing anywhere.

Absence from the FDA, the EMA and the MHRA means there is no reviewed label in those systems, no approved indication, no enforced manufacturing standard for what is shipped to buyers in those countries, and no post-marketing surveillance stream. It also means English-language readers cannot look up a protocol, a result or an adverse event summary in the registry they know how to use.

The practical consequence is the one people skip: a research chemical vial or spray is not the registered medicine. It carries the same name and none of the accompanying guarantees.

Every calculation above starts from a printed number, and three assumptions hold it up.

Identity and purity are the first. A stated 5 mg is a claim about a batch, and only an assay connects a printed figure to a measured one. A certificate supplied with the product describes a batch, which should be matched against the vial in hand rather than accepted as a general assurance.

The device rating is the second. On the vial side the barrel can be inspected, and a U-40 syringe makes one unit 0.025 mL rather than 0.01, which is a factor of 2.5 waiting for anyone who assumes. On the spray side the pump gives no feedback at all, so its rating is either published or unknown.

Stability is the third. Reconstituted liquid is a less stable arrangement than sealed lyophilised powder, and nothing in the arithmetic tracks the decline. A concentration is computed once and then quoted for as long as the container is in use.

An encyclopaedia entry can stop at the molecule and be complete. Anyone holding a container cannot, because every question they are about to ask is answered by the container rather than by the definition.

How much is in one event, how many events are in this bottle, what does this cost per mg, why does a friend's figure differ from mine by a factor of two: all four are answered by mass, volume and delivered volume. None of them is answered by the fact that the molecule is a heptapeptide derived from tuftsin.

That is also the boundary of what this page will do. It converts between containers and quantities. It does not tell anyone what to take, because the arithmetic has no access to that question and the Western evidence record has nothing to supply in its place.