Selank for Sale: A Quantity Result Can Contradict the Listing

Selank for sale listings are built almost entirely out of statements that cannot be checked. Pharmaceutical grade, research grade, highest purity, third party tested and lab verified are not measurements; they are adjectives with no method attached, and no reader can fail any of them. The small number of statements on a listing that can be failed therefore carry the whole signal.

There are four of them: what the compound is, how pure the tested sample was, how much material the container held, and which lot the answers belong to. This article reads one published listing and its certificate against those four, and spends most of its time on the third, because a quantity figure is the rarest thing in this market and the easiest to verify against the seller’s own other products.

Selank for sale: which listing statements can actually be failed

Sort the claims by whether a specific observation would disprove them. The right-hand column is that observation, and if no observation belongs there, the claim is decoration.

A listing that scores well on the top four and says nothing in the bottom three is a better listing than one that reverses that, regardless of which looks more professional. The same sorting exercise for a different compound is set out in our guide to which listing claims are testable.

The 12.29 mg line, and what it is actually worth

The certificate published for lot 29-01260229, analysed on 2026-02-07, reports a measured quantity of 12.29 mg per vial by HPLC-UV quantification against a 10 mg label. That is 22.9 percent above label. Most listings in this market do not report an assayed quantity at all, so the first thing to notice is not the size of the number but the existence of it.

Publishing an assayed quantity is asymmetric in a way that publishing a purity figure is not. A purity result has a comfortable ceiling and almost always lands in the high nineties. A quantity result can come in under the label, in public, on a document a customer will read before buying. A vendor that publishes the line has accepted that risk across every future lot, and that is the part worth crediting.

It is emphatically not a standing overfill, and the same vendor’s other certificates are the proof. Read across three published lots from the same catalogue:

Three lots, three margins, all above label and none of them the same. Anyone quoting the 12.29 mg figure as though it were a specification is misreading a measurement as a promise.

The arithmetic is still worth doing, provided it is labelled correctly. At $47.50 list, halved to $23.75 with the checkout code, the label basis is $2.38 per milligram. On the assayed mass for that one lot it is $23.75 divided by 12.29, or $1.93 per milligram. The second figure is real for that lot and hypothetical for any other, which is a different situation from the compounds where the labelled milligram is the only number anyone has. The full per-milligram treatment, including what the quantity tiers do separately, is in our breakdown of the price of a vial that assayed above its label. Our companion piece on why a milligram that is weighed rather than assayed leaves a gap in the arithmetic sets out what is missing when no quantification result exists at all.

The purity line, read the way the certificate asks

The stated figure is 99.32 percent by HPLC-UV, and the certificate prints the peak list behind it rather than asserting it: two detected peaks, one at 7.13 minutes carrying 99.32 percent of the integrated area and one at 6.36 minutes carrying 0.68 percent, with UV detection across 210.1 to 396.6 nm. The two figures sum to 100, which is the signature of an area-percent normalisation.

That construction has a consequence worth stating plainly. The figure describes the proportion of what the detector saw, so anything the detector did not see is not in the denominator. The certificate makes the point itself, noting that injectable peptides may contain salts and sugars added to aid solubility and buffer pH, that these are not normally detected by UV, and that they are not considered impurities. A purity number constructed this way is a real result and a narrow one, and a listing that quotes the number without the construction is quoting half of it.

The identity line, and the number to compare it against

Selank is a synthetic heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, an analogue of the immune peptide tuftsin with a proline-glycine-proline extension at the C-terminus. Its PubChem entry, CID 11765600, gives the molecular formula C33H57N11O9, an average molecular weight of 751.9, a monoisotopic mass of 751.434, and CAS number 129954-34-3. The certificate states an expected monoisotopic mass of 751.43 Da and a measured value of 751.47 Da, which agree to 0.04 Da, roughly 53 parts per million.

The reason to check the expected value against PubChem rather than accepting it is that the expected value is the part a seller controls. A certificate that quotes an expected mass which does not match the published monoisotopic mass for the compound has failed before the measurement is even considered. Here they agree, and the certificate goes further by printing the spectrum: a doubly charged ion at m/z 376.734 and a singly charged ion at m/z 752.457, which is the charge-state pattern a peptide of this mass produces under electrospray ionisation. There is also an unlabelled feature near m/z 1504.9 that the certificate does not comment on.

What is not on this listing, and what that means

Two test classes are absent from the February certificate entirely. Searching that document for endotoxin, LAL, pyrogen or sterility returns nothing, and the same is true of heavy metals and residual solvents. It covers identity, purity and quantity, and that is its whole scope.

Those omissions line up with the specific concern FDA has published about this substance: that compounded drugs containing selank acetate may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities. Aggregation and impurity burden are analytical questions, and the microbiological panel is the part of the answer this certificate does not contain.

It is worth noting that the capability exists on later batches. The same vendor’s June Semax certificate for batch 30-05260628 carries a kinetic endotoxin assay to USP Chapter 85 reporting below 0.20 EU/mL against a 0.5 EU/mL acceptance limit across a 2.0 mL dilution volume, a rapid two-day sterility screen returning no growth for bacteria and fungi, and a heavy metals screen returning negative for arsenic, cadmium, lead and mercury. So does the vendor’s June Selank batch, 29-05260628, certified thirteen days earlier. The fair reading is chronological rather than product by product: the February documents for both compounds have no microbiology, and the June ones come from a different laboratory on a newer template. This listing quotes the older programme, so read every certificate shown on the product page rather than only the one that is a clickable link, and ask the seller which batch will ship. Our broader treatment of listing claims a certificate cannot cover works through the same boundary for a different compound.

The fields a listing declares before any test is mentioned

Four descriptive fields sit upstream of the analytical ones, and a listing that is vague about them cannot be rescued by a good certificate, because the certificate will be describing a different object from the one being sold.

• Physical form. Lyophilised powder, solution, or finished spray. The certificate discussed here describes a lyophilised powder, and the Semax reports state the condition explicitly as lyophilised on the sample information line. A listing that does not commit to a form has not told you what arrives.
• Labelled quantity and strength. Ten milligrams in one vial is a different purchase from ten milligrams split across two, and per-milligram comparisons silently assume the first.
• Container and closure detail. The Kovera report for the Semax batch records a red cap and a silver crimp on its sample information page. That is a small thing which becomes useful on arrival, because it is a physical property of the batch that a document predicted in advance.
• Storage condition as supplied. A powder and a reconstituted solution have different storage requirements and different shelf lives, and a listing that declares neither is leaving the buyer to guess at the one variable they control after delivery.

What no Selank listing is entitled to claim

No listing can describe this compound as approved, prescribed, therapeutic or safe, because no regulator has assessed it for any indication. Selank holds a Russian registration as an anxiolytic, which is a national registration decision rather than an FDA approval and is not evidence of efficacy by the standards this hub applies. The readable English-language literature is animal and cell work.

A listing that stays inside those limits and publishes checkable numbers is doing the only two things a listing in this market can honestly do. If you want those checks turned into a weighted score with the rule fixed in advance, our scoring method for Selank suppliers publishes the weights before applying them, including to the listing read above.