SELANK lab tests

Seven checks before you trust a SELANK certificate

The same seven questions decide whether a certificate of analysis means anything, whichever compound it describes. Six are about the document; the seventh is about what no document can tell you.

1. An independent, batch-matched COA. The certificate must name the batch or lot in your hands, and must come from a laboratory the vendor neither owns nor pays. A specimen certificate from an earlier lot proves nothing about the vial you were sent.
2. HPLC purity, read against a known band. A purity figure is only informative against the distribution for that compound. "Above 98%" is not a claim — the useful question is whether the result sits inside the range the rest of the market reports. How to read HPLC and mass-spec results.
3. Mass-spectrometry identity. HPLC says how much of the sample is one thing; it does not say which thing. Only a mass-spec result establishes identity, and it is the only check that separates compounds a few daltons apart. Contamination is not hypothetical: research-grade custom peptides from two independent commercial suppliers were found to carry contaminating peptides at roughly 1% by weight, enough to produce false-positive results in immunology assays (Clinical and Vaccine Immunology, 2008 — a study of HIV vaccine peptide libraries rather than of any compound on this site).
4. Net content, measured rather than assumed. Purity and quantity are different questions: a vial can be 99.7% pure and still contain two thirds of the labelled mass. Why 10 mg isn't 10 mg.
5. Endotoxin (LAL) on the batch. An absent endotoxin line means the batch was not tested — not that it passed. Endotoxin testing and LAL interpretation.
6. Who ran the test, and what they left off. A laboratory with a record on this compound, named on the certificate, with a verification route back to it. Testing laboratories we track · Red flags in a certificate of analysis.
7. What no test on the vial can establish. A perfect certificate confirms that a vendor sold the correct molecule at the stated quantity. It says nothing about efficacy, dosing, or long-term safety.

Want a vial tested yourself? How to send a peptide for independent HPLC testing.

What Selank testing has to rule out — and the separate Semax trap

Selank is the heptapeptide Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP): CAS 129954-34-3 (PubChem CID 11765600), formula C₃₃H₅₇N₁₁O₉, molecular weight 751.9 g/mol (monoisotopic 751.434), UNII TS9JR8EP1G, development code TP-7. It was made by attaching a Pro-Gly-Pro tail to tuftsin (Thr-Lys-Pro-Arg), a natural immunopeptide from the heavy chain of human immunoglobulin G. Semax, at 813.93 g/mol, is far enough away that any mass spectrometer separates the two, so confusing them is not the realistic failure. For Selank the realistic failures are tuftsin at roughly 500 Da or a truncated synthesis, and both show as a wrong mass.

One online chemical database's Selank entry lists "PL14736" as a synonym. PL14736 is BPC-157, an entirely different peptide, so that record routes anyone cross-checking a Selank certificate to the wrong molecule and should not be used as a synonym source for this compound.

Selank's tested content on this platform (verified August 2026) ran from −10.3% to +28.6% against the label, including a June 2026 test returning 12.86 mg in a vial labelled 10 mg. An overage of that size is evidence that fill accuracy is uncontrolled at that vendor; the same process that overfills one vial underfills another. Endotoxin reporting is sparse across Selank listings.

Semax — identity. Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), CAS 80714-61-0 (PubChem CID 9811102), formula C₃₇H₅₁N₉O₁₀S, 813.93 g/mol by FDA's own figure, UNII I5FAL2585H; the acetate salt has its own CAS, 2828433-33-4, formula C₃₉H₅₅N₉O₁₂S and mass 874.0 g/mol. The Semax-specific risk is substitution rather than contamination: N-Acetyl Semax Amidate, a modified derivative with a different mass, is sold alongside it, and an HPLC purity figure cannot say which of the two is in the vial. Mass spectrometry against 813.93 Da for the free base settles it, and the certificate should state explicitly that the derivative was excluded. Semax research material is supplied as a TFA salt with molecular weight quoted on a free-base basis, so a certificate that does not name the salt is quoting a number that cannot be converted. PubChem's record title for CID 9811102 reads "ACTH (4-7), Pro-Gly-Pro-" rather than "Semax"; that is not a mismatch.

Semax — quality record. FDA's May 2026 briefing document described both Semax forms as "not well-characterized", with missing impurity, aggregate, endotoxin and bioburden data; it flagged "inconsistent naming conventions that do not follow established chemical nomenclature standards" and raised "potential for immunogenicity associated with these impurities and peptide related aggregates." Endotoxin appears on a minority of Semax listings, at 0.05 to 0.096 EU/mL where reported at all. Tested content ran −2.1% to +22.3% against the label (verified August 2026), and recent purity results sat in a tight 99.00–99.90% band, which shows the synthesis is under control but not which molecule was synthesised. Semax is built from ACTH(4-7) yet has no corticotropic activity, so product copy describing it as a form of ACTH is wrong about mechanism.

Both compounds: articles on Selank and Semax routinely quote an "Elena Yaroslavtseva" of the Institute of Molecular Genetics, and no such researcher exists — a PubMed author search under that surname returns five records unconnected to peptides or the institute. The real programme runs through Nikolay F. Myasoedov and Lyudmila A. Andreeva at the Institute of Molecular Genetics RAS. A page that invents an expert is rarely accurate about anything else, including its own certificates.

• Selank: mass near 751.9 g/mol (monoisotopic 751.434) on a batch-matched certificate, not tuftsin at roughly 500 Da or a truncation.
• Semax: mass at 813.93 Da for the free base, with N-Acetyl Semax Amidate explicitly excluded.
• Semax: the salt form named — TFA, or acetate at 874.0 g/mol. 874.0 quoted as the free base is a red flag.
• Both: quantitative content testing (+28.6% on Selank and +22.3% on Semax are on record) and an LAL endotoxin result on the batch.