Selank Price: $2.38/mg on a Vial That Assayed Higher

The Selank price at the supplier linked below is $47.50 for a 10 mg vial, reduced from a $60.00 strike-through, and $23.75 with the code PEPTIDEDECK. That is $4.75 and $2.38 per labelled milligram. There is one presentation, so there is no vial-size comparison to run.

The interesting arithmetic is not in the cart. The certificate published for the current lot reports a measured quantity of 12.29 mg in a vial labelled 10 mg, which moves the per-milligram figure by a fifth. It also stops short of two tests, and the second half of this page is about what that omission costs, since it cannot be priced.

The listing whose figures are worked through below:

What the Selank price is, at list and with the code

The published quantity tiers apply to the list price: 3 percent off at three vials, 5 percent at five, 10 percent at ten. They are modest, and the table exists mainly so the last row has something to be measured against.

The bottom row is not a variation on the four above it. Ten vials at the 10 percent tier save $47.50 across a $475.00 basket; the code saves $23.75 on a single $47.50 order. Whether the code applies to more than one vial in a basket, and whether it combines with a tier, is not stated anywhere in the published terms, so this page does not assert that it does. Build the basket, enter the code, read the order summary before paying. The line-by-line version of that check sits on our page on the discount code.

Carriage is free above $250. Five vials at the tier price of $225.63 does not clear the threshold and ten at $427.50 does, which is worth knowing before free shipping is used as a reason to buy twice what you need.

The per-milligram figure the certificate actually supports

The supplier publishes a certificate of analysis for lot 29-01260229, analysed on 7 February 2026 by MZ Biolabs in Tucson, Arizona. Three results sit on it, and each carries a different weight.

• Purity 99.32 percent by liquid chromatography with ultraviolet detection. Two peaks were detected across the run: one at 6.36 minutes carrying 0.68 percent of the integrated area, and the Selank peak at 7.13 minutes carrying the rest. This is an area percentage of what absorbed light and eluted, which is not the same statement as a mass fraction of the vial.
• Identity by mass spectrometry. The expected monoisotopic mass is 751.43 Da and the instrument measured 751.47 Da, a difference of 0.04 Da, or roughly 53 parts per million. For a seven-residue peptide that is a match. It is also the check that most deserves to exist, because a pure vial of the wrong compound passes a purity test cleanly.
• Measured quantity 12.29 mg per vial against a 10 mg label. Publishing a quantification result at all is unusual in this market, and publishing one that shows an overfill rather than a shortfall is unusual again.

Run the division both ways and the gap is not trivial. At the discounted $23.75, the price per labelled milligram is $2.38 and the price per assayed milligram on that lot is $1.93. At list, $4.75 becomes $3.86. Every retailer quotes the first number, because the first number is the only one a seller without an assay can quote.

The reason to state it as a lot result rather than a feature is that a fill weight is a manufacturing outcome, not a specification. Nothing in the document promises 12.29 mg in the next vial, and a reader who converts a single measurement into an expectation has repeated the error the measurement was published to prevent. Ask for the certificate that bears the lot number on the vial you were sent. The same principle drives our reading of the label mass in what a BPC-157 milligram costs, where the mass is weighed rather than assayed and the gap runs the other way.

Two certificates from one supplier, two standards of documentation

This supplier publishes a February and a June certificate for each of Selank and Semax, and the two analysis windows do not carry the same tests. The table below sets the February Selank document against the June Semax one, which is the widest gap available, but the same split exists inside each compound: which panel you get is a batch question rather than a product question.

That contrast took us about a minute to establish and it is the single most useful thing on this page. It is also worth being fair in both directions. The June report says of itself that its rapid screen is a preliminary assessment and that full compendial sterility testing may be required for regulatory purposes, so it is a screen and not a guarantee, which is a candid note that most vendor documents would omit. And the February Selank certificate is a real analysis from a named chemist at a named laboratory with a visible chromatogram, which puts it ahead of the majority of what this market publishes. The point is narrower than a verdict: at this supplier the wider panel arrived in June, on Selank batch 29-05260628 as well as on Semax, so the tests you get depend on which batch ships. Read every certificate shown on the product page rather than only the one that is a clickable link, because the fuller testing is often present as images while the linked PDF is the older, thinner document.

Why the line that goes missing is the one the regulator points at

FDA has published a safety assessment of this compound under the name selank acetate. The agency wrote that compounded drugs containing it may pose risk for immunogenicity for certain routes of administration due to the potential for aggregation and peptide-related impurities, and that it lacks important information regarding any safety issues raised by selank acetate administered to humans.

Read that as an analytical statement rather than a rhetorical one and it names its own tests. Aggregation is a physical state of the peptide in solution. Peptide-related impurities are the deletion, truncation and modification products that chromatography is run to find. Neither concern is answered by a price, and only one of them is answered by a February certificate. Bacterial endotoxin, the pyrogenic contaminant that FDA addresses in its own questions and answers on pyrogen testing, is a separate measurement again, and it is the one that appears on the June batches and not on the February ones.

None of that is a reason to treat the compound as prohibited, and it is worth correcting a claim that circulates widely: Selank does not appear anywhere in FDA's list of substances nominated for compounding under section 503A, in any of its three categories, in the document updated on 14 May 2026. Its nomination was withdrawn, which is a different administrative fact with different consequences, and we set it out in full on our page on the legal position.

What a price cannot settle

Price is a commercial setting chosen after the fact. Identity, purity, quantity and endotoxin load are measurements made on a lot before any number was attached to it, and a result is only as good as the method behind it, which is the principle ICH Q2(R2) sets out for regulated analytical work. Research-supply certificates sit under no such obligation, so a named laboratory, a report date, a lot number and a visible chromatographic trace matter more than a large percentage in a large font.

What the money also does not buy is a settled case for the compound. Selank is a synthetic seven-residue peptide, PubChem CID 11765600, formula C33H57N11O9, an analogue of the immune peptide tuftsin extended at the tail to slow enzymatic breakdown. It carries a Russian registration as an anxiolytic; that is a fact about a foreign regulatory system and not evidence by Western standards, and we report it without adopting it. The published mechanistic work is largely preclinical, and the review by Vyunova and colleagues is the most useful English-language entry point into it. There is no FDA marketing authorisation for any indication.

Nothing on this page describes or implies human use, and there are no quantities here because quantity is not a price question. For how this site grades material sold under research-use terms in general, see what research-use supply actually means, and for the same arithmetic applied where a certificate does carry an endotoxin result, our analysis of what a cheaper gram leaves untested works through the version of this problem where the missing test has documented consequences.