Key points
- Semaglutide bought from illegal online pharmacies: 7.7 to 14.4% purity vs 99% claimed, and endotoxin in every sample [1].
- Falsified peptides bought from illegal online pharmacies (Belgium): 5 to 75% purity in some, arsenic up to 10 times the limit for injectables, and lead in one sample [2].
- Haemolytic Bacillus cereus was found in two illegal injectable peptides [3].
- We found no published independent purity or contamination analyses of BPC-157 or TB-500 sold to the public.
US status (October 2026): See the peptide status tracker.
A label is the only assurance outside the regulated chain
The labs that have tested peptides bought outside the regulated pharmaceutical chain found problems the label did not disclose. When a patient buys that way, they rely on the label or a certificate of analysis on a website. Several official and academic labs have put that to the test. Their results help explain why regulators in Latin America issue alerts [6][7], and why you should ask where a patient’s vial came from.
Online semaglutide failed on purity and endotoxin
A 2024 study tracked semaglutide sold without a prescription. Of 317 pharmacy links, 134 (42.3%) led to 59 illegal sites. The study team placed 6 orders: only 3 vials arrived and the pens were never delivered [1]. In the lab, purity was 7.7 to 14.4% vs the 99% claimed, content was 28.6 to 38.7% above label, and endotoxin was present in every sample, although no viable microorganisms were found [1].
- 7.7 to 14.4%: actual purity vs 99% claimed [1]
- 100%: of samples contained endotoxin [1]
- 3 of 6: orders never arrived [1]
The approved products are covered on the semaglutide status page, and the rules for compounded versions in compounded GLP-1s after the shortage.
Belgian testing found metals and bacteria
Belgium’s Scientific Institute of Public Health analyzed the ten most frequently encountered falsified peptides on its market, bought from three suspected illegal internet pharmacies. Amount per unit varied widely. The cysteine-containing peptides had purity of 5 to 75%. Several samples contained arsenic (all in inorganic form) up to 10 times the ICH limit for parenteral products, and one was contaminated with lead [2]. The same group documented haemolytic Bacillus cereus in two illegal injectable peptides [3].
Growth hormone came underdosed and analogs went undeclared
A study of somatropin (growth hormone) sold online found that 94% of 17 vendors required no prescription and that every sample contained less somatropin than labeled [4]. In another case, a seized vial contained a new peptide, a GHRP-2 analog not previously described [5].
No published lab test covers BPC-157 or TB-500
Despite their popularity, we found no independent PubMed-indexed purity or contamination analysis of BPC-157 or TB-500 vials sold to the public (search of October 9, 2026). An anti-doping lab only identified BPC-157 in confiscated vials and developed its detection in urine [10]. The alerts from INVIMA and Guatemala’s Health Ministry start from that lack of quality evaluation [6][7]. US status for both is on the BPC-157 and TB-500 pages.
Certificates of analysis are the point of dispute
Sellers often offer per-lot certificates of analysis. Regulators answer that these products “have not been evaluated in terms of quality, safety or efficacy” and that every person has the right to know what is being sold to them [6][7]. The FDA also notes that the semaglutide salts (sodium or acetate) found in some products are different active ingredients from the approved one [8].
How to read a certificate of analysis. A useful certificate identifies the exact lot, the lab that issued it and the method (for example, HPLC for purity and mass spectrometry for identity). The studies cited here also measure what a purity certificate usually does not cover: endotoxin, metals and microbial contamination [1][2][3]. A longer walkthrough is in how to read a peptide certificate of analysis.
The other side. Read these studies precisely. They tested products from illegal online pharmacies or seized products [1][2][3][4][5]. Products sold with per-lot certificates from independent labs have not been tested in a published comparison. Supporters of a regulated route argue that giving these products standards reduces gray-market risk [9].
What this means for your clinic
Ask every patient on a peptide where the vial came from, and document it. A certificate of analysis that covers purity alone leaves out endotoxin, metals and microbial testing, which are the failures these studies found. For a supplier checklist, see peptide supplier diligence, and for what a “research use only” label does and does not permit, see research-use-only peptides.
References
- Ashraf AR, et al. Multifactor quality and safety analysis of semaglutide products sold by online sellers without a prescription: market surveillance, content analysis, and product purchase evaluation study. J Med Internet Res. 2024;26:e65440. PMID 39509151. Link
- 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. Link
- Janvier S, et al. Are injectable illegal polypeptide drugs safe? Case report demonstrating the presence of haemolytic Bacillus cereus in 2 illegal peptide drugs. Drug Test Anal. 2018;10(4):791-795. PMID 28941153. Link
- Vida RG, et al. Availability and quality of illegitimate somatropin products obtained from the Internet. Int J Clin Pharm. 2017;39(1):78-87. PMID 27888454. Link
- Popławska M, et al. Identification of a novel growth hormone releasing peptide (a glycine analogue of GHRP-2) in a seized injection vial. Drug Test Anal. 2019;11(1):162-167. PMID 30051972. Link
- INVIMA (Colombia). Alerta Sanitaria No. 184-2026 (DSIP, Selank, Semax, PT-141, ipamorelina, CJC-1295, BPC-157, GHK-Cu, TB-500 y retatrutida). Bogotá, 24 de junio de 2026. Link
- Galicia S. El Ministerio de Salud de Guatemala advierte que los péptidos inyectables sin registro sanitario se venden de forma ilegal. Infobae. 6 de agosto de 2026. Link
- U.S. Food and Drug Administration. FDA’s concerns with unapproved GLP-1 drugs used for weight loss. Updated 1 October 2026. Link
- McDermott Will & Schulte. Bulk list bound? PCAC backs majority of peptides in two-day public meeting. 27 July 2026. Link
- Cox HD, et al. Detection and in vitro metabolism of the confiscated peptides BPC 157 and MGF R23H. Drug Test Anal. 2017;9(10):1490-1498. PMID 28035768. Link
This is general information, not medical or legal advice. Rules vary by state and change. Confirm your own facts with counsel.