How to read a peptide COA and verify a lab result

In short. A COA, or certificate of analysis, is a lab report on a sample. A good COA answers four questions: is it the right substance, how pure is it, how much is there, and does it contain harmful contaminants. Many certificates seen online answer only one or two.

Four different questions

In medicines quality control, a peptide is tested for identity, purity and strength, that is, amount, and each needs its own method [1].

Typical impurities in synthetic peptides include chains missing an amino acid or carrying an extra one. The EMA guideline covers these as "deletion", "truncated" and "insertion" sequences [4]. They can show up in HPLC as small peaks next to the main peak.

When label and reality differed

Several studies have analysed peptides bought online or seized. Most are small, and none describes the whole market. Together they show that a number on a label is not a measurement. The errors fall into four types.

1. The wrong substance, or nothing

• A Belgian official laboratory identified AOD-9604 in seized preparations whose contents were unknown [22].
• In Denmark, 9 of 36 seized peptide samples contained no peptide or protein at all [11].
• German and Norwegian doping labs found modified molecules in black-market products, such as ipamorelin and GHRP peptides with an extra amino acid added. The vial did not contain the labelled substance [12].
• In a French study, the contents of products sold online as TB-500 did not consistently match their description [20].

2. The amount is off in both directions

• In Australia, three "10 mg" retatrutide vials held 5.1, 16.5 and 19.0 mg of retatrutide, that is, 51-190% of the label [9].
• Semaglutide vials bought online without a prescription held 29-39% more than the label [2].
• Melanotan II vials held 4.3-8.8 mg instead of the promised 10 mg [10].

Too much is as real a risk as too little.

3. Purity falls short of the claim

• Doping labs found oxidised and unpurified forms in black-market IGF-1 LR3 products: what was found in seized products.
• Semaglutide vials claimed 99% purity. Measured purity was 7.7-14.4% [2].
• A Belgian official lab bought the ten most common falsified peptide drugs from illegal online pharmacies. Some were only 5-75% pure [8].

4. Contaminants in an injection

• Endotoxin was found in all three semaglutide vials bought online, at 2.2-8.9 endotoxin units (EU) per milligram. No viable microbes were found [2].
• In the Belgian study some products contained arsenic at up to ten times the limit for injectable medicines, and one contained lead [8].

What a large community dataset shows

The largest dataset is a public collection of test results on samples sent in by users and sellers. A study not yet peer reviewed examined 6,441 samples of 14 peptides, including BPC-157, TB-500, retatrutide, tirzepatide and semaglutide. Depending on the quality standard, 42-71% of samples failed basic criteria, and 15% contained measurable endotoxin [13]. The people who sent the samples chose them, so the figure does not describe the whole market.

What this leaves us with. The studies are few and small, but the same problems recur across countries and peptides. For BPC-157 and TB-500 we found no peer-reviewed study that measured amount or purity, so data on their amount and purity comes only from community testing. A French TB-500 study examined whether the contents matched the product description [20].

How to read an HPLC result

An HPLC report shows a curve in which each peak is one component of the sample. The purity percentage is usually the main peak's share of all peaks. So 99% can be true and still misleading: if the main peak is the wrong substance, purity only tells you there is a lot of the wrong substance. Identity needs a separate measurement such as mass spectrometry [1]. An example with a 37-amino-acid peptide: why a long peptide needs two measurements. A good report shows the curve itself, not just a number.

Endotoxin is usually reported in endotoxin units (EU) per milligram, written EU/mg. In the semaglutide vials bought online, levels were 2.2-8.9 EU/mg [2].

What users themselves say

User discussions repeat the same order of trust: your own tested order, then another user's test of the same batch, and only last the seller's own certificate. Seller COAs are called adverts, and many warn that a certificate can be copied or edited [7]. That is why being able to verify the result in the lab's own system is the single most important point.

Who tests peptides and why people trust Janoshik

A few lab names keep appearing on certificates for peptides sold online. The best known is Janoshik in the Czech Republic [21]. Many assume it is accredited, that is, officially approved. According to the Czech accreditation register, it is not [14].

What accreditation actually means

Lab competence is assessed against the ISO/IEC 17025 standard. Each country's accreditation body does the assessment: FINAS in Finland, ČIA in the Czech Republic. Accreditation is not a stamp for the whole lab. It is granted for specific tests on specific sample types, listed in the lab's scope of accreditation. A certificate from the US body A2LA says so directly: accreditation shows competence for a defined scope [17].

So the right question is not "is the lab accredited" but "is this test, on this substance, in the lab's scope". For example, Vanguard Laboratory, ACS Laboratory and Harrens Lab are US labs that the community mentions as accredited peptide testers, and Harrens Lab tests peptides for the Finnrick platform [19][21]. According to the A2LA register, their scopes cover areas such as food microbiology, metals, cannabis, kratom and mushrooms. None of them covers peptide identity, purity, amount or endotoxin [17][18]. We found no accreditation that covers "research peptides" as such.

Janoshik: no accreditation, but a long reputation

Register facts. Janoshik s.r.o. is a company registered in Prague in 2022, with technical testing and analysis among its registered activities [15]. The register of the Czech accreditation body ČIA has no entry for Janoshik by name or company number [14]. The lab does not claim accreditation itself. It describes itself as an independent lab with over ten years of experience and verifiable results [16]. The current company was founded in 2022, so the longer history is the lab's own statement [15][16].

Reputation, not a certificate. Users trust Janoshik for other reasons [21]:

• Results can be verified. A report can be checked in the lab's own system [16], so an edited or borrowed certificate gets caught.
• Anyone can send a sample. A user can test their own vial, and the result does not pass through the seller. The lab's price list includes a blind test for weight-loss drugs, in which the lab works out whether the vial holds semaglutide, tirzepatide or retatrutide rather than just confirming the seller's claim [16].
• Long history and comparison. The community compares the same batch across labs and treats Janoshik as a reference point [21].

Weaknesses. The lab's own pages say nothing about method validation or results from proficiency tests in which an outside body checks its accuracy [16]. The public results list mostly shows tests that sellers chose to publish, so sellers are a major customer group [16]. Different labs can report different numbers for the same vial [21]. A test describes one vial on one day.

Testing platforms

Some services are not labs themselves. The US service Finnrick, for example, collects samples from users and sellers, sends them to several labs and publishes the results. According to its own site it had close to 12,000 tests by the end of September 2026, with HPLC as the primary method for peptides [19]. The dataset is large, but it is not a random sample of the market, because the people sending samples choose them.

Who tests officially

Official medicines control labs test seized and illegal products. A Belgian official lab, for example, validated its peptide identification method to ISO 17025 requirements [3]. Grey-market users, by contrast, have their products tested by commercial labs [21]. In the ČIA and A2LA registers, no commercial lab named on this page has a scope that covers peptide tests [14][17][18].

COA checklist

1. Batch number on the certificate matches the vial.
2. The lab is named and the result can be verified in the lab's own system with a code or link. If it cannot be verified, the certificate is a seller claim.
3. The date is recent and refers to this batch, not a "representative sample".
4. Both identity (MS) and purity (HPLC) were measured. A percentage alone is not enough.
5. The amount in milligrams was measured, not just stated.
6. For a blend, each part was identified and its amount measured separately: why a blend's COA is a different matter.
7. For injectables, endotoxin and sterility were tested.
8. Lab competence. If the certificate mentions accreditation, check it in the accreditation body's own register and see whether the specific method and substance are in the lab's scope. An accredited lab can also run tests its accreditation does not cover [17].

Why this does not remove the risk

Even a good COA does not make a product a medicine. It describes one sample on one day. Fimea says there is no reliable information on the content, quality and safety of peptides sold online [5]. A Belgian official lab had to identify research peptides in seized unknown preparations using combined liquid chromatography and mass spectrometry [3].

Next: mixing and sterility, side effects and legal status in Finland.

FAQ

Sources

1. McCarthy D, et al. Reference Standards to Support Quality of Synthetic Peptide Therapeutics. Pharm Res. 2023;40(6):1317-1328. PMID 36949371
2. Ashraf AR, et al. Multifactor Quality and Safety Analysis of Semaglutide Products Sold by Online Sellers Without a Prescription. J Med Internet Res. 2024;26:e65440. PMID 39509151
3. Vanhee C, et al. The occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations. Drug Test Anal. 2020;12(3):371-381. PMID 31667971
4. EMA: Guideline on the development and manufacture of synthetic peptides (EMA/CHMP/CVMP/QWP/367182/2025). ema.europa.eu
5. Fimea: Fimea warns: do not use injectable peptides purchased online. 29 Jun 2026. fimea.fi
6. Swissmedic: Cross-agency targeted campaign "Peptides 2026". 30 Jun 2026. swissmedic.ch
7. Reddit discussions in r/Peptides and r/Retatrutide, March-October 2026: editorial summary of 419 comments on testing, read on 6 Oct 2026.
8. Janvier S, et al. Impurity profiling of the most frequently encountered falsified polypeptide drugs on the Belgian market. Talanta. 2018;188:795-807. PMID 30029448
9. Piatkowski T, et al. Composition and Labelling Accuracy of Products Sold as Retatrutide in Australia. Drug Alcohol Rev. 2026;45(6):e70231. PMID 42559975
10. 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):164-172. PMID 24771717
11. Høj LJ, et al. Analysis of seized peptide and protein-based doping agents using four complimentary methods. Drug Test Anal. 2021;13(7):1457-1463. PMID 33686802
12. Krug O, et al. Analysis of new growth promoting black market products. Growth Horm IGF Res. 2018;41:1-6. PMID 29864719
13. Mendias CL, Awan TM. Evaluation of Research Grade Peptides Marketed Directly to Consumers Reveals Extensive Variability in Purity and Measured Abundance. Preprints.org, 24 Apr 2026. Preprint, not peer reviewed. doi.org
14. Czech Accreditation Institute (ČIA): database of accredited laboratories and bodies, as of 13 Oct 2026. Janoshik s.r.o. (company number 17668727) is not listed. cai.cz
15. ARES, Czech business register: Janoshik s.r.o., company number 17668727, established 25 Oct 2022, as of 13 Oct 2026. ares.gov.cz
16. Janoshik: About us, Services and Peptides pages and the public results list, page versions from July 2026, read 13 Oct 2026. web.archive.org
17. A2LA: Scope of Accreditation to ISO/IEC 17025:2017, Olympic Analytical LLC dba Vanguard Laboratory (certificate 6377.01) and Harrens Lab Inc. (certificates 4074.01 and 4074.02), as of 13 Oct 2026. a2la.org
18. A2LA: Scope of Accreditation to ISO/IEC 17025:2017, ACS Laboratory LLC (certificate 6786.01), as of 13 Oct 2026. a2la.org
19. Finnrick: home, methodology and labs pages, updated 29 Sep 2026, read 13 Oct 2026. finnrick.com
20. Delcourt V, et al. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal. 2023;15(4):458-464. PMID 36482504
21. Reddit discussions in r/Peptides, r/UK_Peptide_Sources and r/wholesale_suppliers and peptide forums, September-October 2026: editorial summary of discussions about testing labs. Opinions and experiences, not measurements.
22. Vanhee C, Moens G, Deconinck E, De Beer JO. Identification and characterization of peptide drugs in unknown pharmaceutical preparations seized by the Belgian authorities: case report on AOD9604. Drug Test Anal. 2014;6(9):964-968. PMID 24976118

Sources 1-7 checked in PubMed and on the EMA and Swissmedic websites on 6 Oct 2026. Sources 8-21 and the accreditation and company register entries (ČIA, ARES, A2LA) checked on 13 Oct 2026. Source 22 checked in PubMed on 14 Oct 2026. Source 13 is a preprint that has not been peer reviewed.

Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.