Counterfeit, mislabeled and under-filled peptide products aren't a rumor. They are documented in the peer-reviewed analytical literature, by official medicines control laboratories and doping-control labs that buy or seize products and test them.
For a laboratory, the consequence is simple. If the material in the vial isn't what the label says, every result built on it is compromised. This guide covers what published analyses have found, the practical warning signs, and what a genuine lot record should let you check.
What published analyses have found
Wrong amount in the vial
In a Danish study, researchers bought melanotan II vials from three online shops and developed validated methods to measure identity, content and purity. Each shop claimed 10 mg per vial. Measured content ranged from 4.32 mg to 8.84 mg. Vials from two of the shops also contained unknown impurities at 4.1–5.9% (Breindahl et al., 2015; DOI: 10.1002/dta.1655).
The molecule was real. The quantity was not. A buyer checking identity alone would have missed it.
Low purity and toxic elements
Belgium's Scientific Institute of Public Health systematically screened the ten most frequently encountered falsified peptide products on the Belgian market, bought from three suspected illegal internet pharmacies. They looked beyond the main ingredient: peptide-related impurities, small-molecule contaminants, elemental impurities and residual solvents. They found:
- high variation in the amount of peptide per unit;
- purities between 5% and 75% for cysteine-containing peptides;
- the toxic elements arsenic and lead, with multiple samples at up to ten times the ICH limit used for parenteral drugs, and the arsenic present in its more toxic inorganic form.
(Janvier et al., 2018; DOI: 10.1016/j.talanta.2018.06.023)
Enough problem products to justify a screening method
The same institute's Official Medicines Control Laboratory published a general LC-MS/MS screening method that can identify 25 different peptides in suspected counterfeit and illegal preparations in 30 minutes, validated to ISO 17025 requirements. The paper notes that these peptides had already turned up in products seized by several European countries (Vanhee et al., 2015; DOI: 10.1016/j.talanta.2015.04.022).
Doping-control laboratories have done similar work on specific products. The Ghent doping-control lab identified the peptide in a product sold as "TB-500" by high-resolution mass spectrometry: an N-terminally acetylated seven-residue fragment of thymosin beta-4 (Ac-LKKTETQ) (Esposito et al., 2012; DOI: 10.1002/dta.1402). That finding matters for buyers. A product name on a label does not tell you which molecule is inside. Only analysis does.
The pattern
Across these studies, the problems fall into four groups:
- Identity. Is it the right molecule?
- Quantity. Is the stated amount actually there?
- Purity. What else is in it: related peptides, solvents, metals?
- Traceability. Can anyone connect the vial to the test?
A counterfeit or low-quality product can fail any one of these while passing the others. That's why no single number, including "99% purity", settles the question.
Warning signs before you buy
None of these proves a product is counterfeit. Each is a reason to ask harder questions.
1. No lot number on the vial. Without a lot number there's nothing to connect a test result to the material. This is the most basic control, and its absence is the clearest warning.
2. A "representative" or generic certificate. One PDF reused across every batch describes a batch, just not necessarily yours. Look for a record tied to your specific lot.
3. A certificate with no laboratory name or date. An anonymous result can't be checked. A named lab and a test date can.
4. Purity only, with no identity data. HPLC purity shows that one component dominates. It doesn't show that the component is the right molecule. Look for mass spectrometry: an observed mass that matches the theoretical one. Our guide to reading a certificate of analysis explains each test. Related reading: How to Read a Peptide Certificate of Analysis: Purity, HPLC and Mass Spec Explained.
5. Typed numbers with no chromatogram or spectrum. Anyone can type "99.4%". An actual trace is much harder to fake convincingly and much easier to question.
6. Prices far below the market. Synthesis, purification and third-party testing all cost money. A price that ignores those costs is telling you something.
7. Health or results claims on a "research" product. A supplier that promises outcomes is marketing to people, not laboratories. That tells you about its controls in general.
8. Vague operator identity. A genuine supplier names the legal entity behind it and gives a working contact address.
Warning signs when the vial arrives
- Label mismatch: a compound name, strength or lot number that differs from your order or the record.
- Tampered or missing seals.
- A cake that looks collapsed, melted, sticky or discolored. Lyophilized material should be a dry, intact solid. Changes can point to moisture exposure or poor storage.
- Unmarked or hand-labeled vials.
- Packaging that doesn't protect the vial. Vials that rattle loose or arrive cracked.
Record the lot number in your lab log on arrival, before anything else happens to the vial.
What a real lot record should show
A genuine lot record is the opposite of every warning sign above. At minimum it should show:
| Field | Why it matters |
|---|---|
| Lot number matching the vial | Connects the evidence to your material |
| Compound, form, container | Confirms what the record describes |
| HPLC purity: specification and measured result | Tells you what was targeted and what was found |
| Chromatogram | Shows the evidence behind the purity number |
| Identity by LC-MS: theoretical vs. observed mass | Confirms it's the right molecule |
| Endotoxin (LAL) result vs. limit | Flags bacterial contamination that can confound experiments |
| Testing laboratory and test date | Makes the result checkable |
| A permanent, shareable link | Lets collaborators and reviewers see the same record |
Good records also include net peptide content, water content and counterion data. These explain how much of the powder is actually peptide, which the Breindahl findings show is a real-world problem.
How Seratide's Lot lookup page works
Seratide was built around the idea that the proof should belong to the lot in your hand, and that you shouldn't have to email anyone to see it.
Every Seratide vial carries a lot number in the form SRT-0000-XXX. You type it into the Lot lookup page and get the record for that lot. There's no app and no login. Each record has a permanent link you can share.
The record is laid out in the format this guide describes:
- lot number, compound, form and container;
- HPLC purity specification and result;
- identity by LC-MS;
- endotoxin (LAL);
- the testing laboratory and test date.
To be clear about where things stand today: the lot records currently on the Lot lookup page are layout samples. They are clearly marked as such and show the format only. Their values are placeholders, not measurements. Issued laboratory reports replace them as each lot is analyzed. We'd rather tell you that plainly than let a sample page pass for a test result. That same standard is the one this article asks you to apply to every supplier, including us.
Seratide is operated by Axe Cap Holdings LLC. You can read more about who we are and who we sell to on our About page, and how orders are packed and tracked on our Shipping Policy.
A short counterfeit-screening routine for your lab
- Before ordering: confirm the supplier publishes lot-level records with a named lab, a date, identity data and a chromatogram.
- On arrival: check seals, label, lot number and cake appearance. Log the lot.
- Match the record: open the record for that exact lot and compare compound, strength and lot.
- For critical work: consider independent confirmation. An LC-MS identity check at your own institution or a contract lab is the same approach control laboratories use.
- Keep the trail: file the lot record with your experimental notes, so anyone reviewing your data can see exactly what material was used.
Why "it's the right molecule" isn't enough
It's tempting to think that once identity is confirmed, the job is done. The published analyses show why it isn't.
In the Breindahl study, every vial tested contained melanotan II, so the identity check passed. But the amount ranged from under half to under 90% of the labeled 10 mg. In the Janvier study, the problems included heavy-metal contamination that no identity or HPLC purity test would reveal. Different failures need different tests:
| Failure | What catches it |
|---|---|
| Wrong molecule | LC-MS identity (observed vs. theoretical mass) |
| Right molecule, wrong amount | Quantification or net peptide content |
| Right molecule, low purity | HPLC with chromatogram |
| Elemental contaminants (e.g. lead, arsenic) | Elemental analysis such as ICP-MS |
| Bacterial endotoxin | LAL or recombinant Factor C assay |
| No link between test and vial | Lot number printed on vial and on the record |
No routine lot record covers every row. The point is to know which rows a record covers and which it doesn't, and to plan independent testing for the gaps that matter to your work.
Sources
All sources below were opened and checked against their PubMed records while drafting.
- Breindahl T, et al. Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet. Drug Test Anal. 2015;7(2):164-72. PubMed: https://pubmed.ncbi.nlm.nih.gov/24771717/ · DOI: https://doi.org/10.1002/dta.1655
- Janvier S, et al. Impurity profiling of the most frequently encountered falsified polypeptide drugs on the Belgian market. Talanta. 2018;188:795-807. PubMed: https://pubmed.ncbi.nlm.nih.gov/30029448/ · DOI: https://doi.org/10.1016/j.talanta.2018.06.023
- Vanhee C, et al. Analysis of illegal peptide biopharmaceuticals frequently encountered by controlling agencies. Talanta. 2015;142:1-10. PubMed: https://pubmed.ncbi.nlm.nih.gov/26003685/ · DOI: https://doi.org/10.1016/j.talanta.2015.04.022
- Esposito S, et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4(9):733-8. PubMed: https://pubmed.ncbi.nlm.nih.gov/22962027/ · DOI: https://doi.org/10.1002/dta.1402
For laboratory research use only.