What's Actually in Your Peptides? The Quality Crisis Nobody Talks About
30% contain the wrong molecule. 65% exceed endotoxin limits. Inside the data that peptide vendors don't want you to see.
The Numbers That Should Worry You
The peptide market has a quality problem that’s far worse than most users realize. Independent testing data paints a disturbing picture:
- 30% of tested products contained the wrong molecule (Rohrbough Drug Testing Analysis, 2020)
- 65% exceeded endotoxin safety thresholds in injectable preparations
- 20%+ were mislabeled or contaminated (USADA testing, 2017)
- Concentration variability of 5–20× the labeled dose has been documented across vendors
These aren’t theoretical risks. Documented adverse events from contaminated or mislabeled peptides include injection site abscesses requiring surgical intervention, sepsis from bacterial contamination, and overdoses from concentration errors.
Without independent third-party testing, you have no way to verify what’s in a peptide vial. Vendor-provided COAs can be fabricated, and the absence of regulatory oversight means nobody is checking. The data shows roughly one in three products from untested sources may not contain what the label claims.
The Scale of the Grey Market
The legitimate peptide therapeutics market is valued at $46–52 billion (2024) and projected to reach $81–162 billion by 2033–2035. But the grey market exists in parallel — unregulated, untested, and growing fast.
Chinese peptide imports to the US doubled to $328 million in the first three quarters of 2025 alone. Online advertising for peptide products increased 308% from 2023 to 2024 and 678% from 2022 to 2024. The demand curve is steep, and supply is racing to meet it with minimal quality controls.
What Independent Labs Are Finding
Finnrick Analytics: The Largest Dataset
Finnrick Analytics has tested over 5,160 samples from 173 vendors — the largest independent peptide quality dataset we’re aware of. Their findings reveal systematic quality issues:
Identity failures: A significant percentage of samples fail basic identity testing — meaning the vial doesn’t contain the peptide stated on the label. This can mean a completely different compound, a degraded product, or simply an empty vial with solvent.
Purity failures: Many samples that contain the correct peptide fall below the claimed purity level. A product claiming ≥98% purity might test at 85% or lower, with the remainder being synthesis impurities, degradation products, or unknown contaminants.
Endotoxin contamination: Bacterial endotoxins (lipopolysaccharides from gram-negative bacteria) are a particular concern for injectable products. Endotoxin exposure can cause fever, inflammation, and in severe cases, septic shock. The 65% failure rate on endotoxin testing suggests widespread production hygiene issues.
Janoshik Analytical: The Gold Standard
Janoshik Analytical is widely considered the gold standard for independent peptide verification. Their QR-verified COAs provide the highest level of confidence currently available:
- Each COA links to a verifiable database entry
- Testing includes HPLC purity, mass spectrometry identity confirmation, and appearance/solubility checks
- Results cannot be retroactively altered
The limitation: Janoshik testing costs $100–350 per sample, and vendors choose whether to submit products for testing. This creates selection bias — vendors who know their products will pass are more likely to test, while those with quality concerns avoid independent verification entirely.
Other Independent Labs
Chromate and MZ Biolabs also provide independent peptide analysis with varying methodologies and reporting formats.
How to Read a Certificate of Analysis
A COA is only as good as the lab that issued it and the tests it includes. Here’s what to look for:
Essential Tests for Injectable Peptides
HPLC (High-Performance Liquid Chromatography): Measures purity. Look for ≥98% purity with a clear chromatogram showing a single dominant peak. Multiple peaks suggest impurities or degradation products.
Mass Spectrometry (MS): Confirms identity — that the molecular weight matches the target peptide. This is the definitive test for whether you have the right compound.
LAL Endotoxin Test (Limulus Amebocyte Lysate): Critical for injectables. Detects bacterial endotoxins. Must be below USP limits (typically <5 EU/kg body weight per dose).
Heavy Metals Testing: Screens for lead, mercury, arsenic, and cadmium contamination from manufacturing processes or raw materials.
Residual Solvents: Tests for leftover chemicals from the synthesis process (TFA, acetonitrile, DMF, etc.).
Red Flags in COAs
No lab name or address: Legitimate COAs identify the testing laboratory.
No batch/lot number: Without batch-specific testing, the COA may not correspond to the product you received.
Suspiciously round numbers: Real analytical results have decimal precision (98.73%, not 99%).
No chromatogram: The HPLC trace should be included — it’s the raw data behind the purity number.
PDF-only with no verification link: Some vendors fabricate COAs. QR-verified links to lab databases (like Janoshik provides) are the best protection against fraudulent documentation.
COA from the manufacturer, not an independent lab: When the company that made the product also tested it, the COA has limited value. Independent third-party testing is what matters.
The Cost of Not Testing
Documented consequences of using untested grey-market peptides include:
Injection site infections: Abscesses requiring surgical drainage have been reported from contaminated preparations. The absence of sterility testing means bacterial or fungal contamination may not be detected until symptoms appear.
Endotoxin reactions: Fever, chills, and inflammatory responses from endotoxin-contaminated injectable peptides. In severe cases, this can progress to septic shock.
Overdose from concentration errors: When the actual peptide concentration is 5–20× the labeled amount, standard dosing protocols produce dangerous overdoses. Conversely, underdosed products provide no therapeutic effect while creating a false sense of treatment.
Wrong compound entirely: Taking a different peptide than intended introduces unpredictable pharmacological effects. Some synthesis impurities may be toxic at concentrations that the intended peptide would be safe.
What Vendors Should Provide (But Often Don’t)
If a vendor is serious about quality, they should make the following available without requiring a customer request:
- Batch-specific COAs (not generic product COAs)
- Independent lab identification (name, address, accreditation)
- HPLC chromatogram (raw data, not just a number)
- Mass spectrometry confirmation of identity
- Endotoxin testing results for injectable products
- QR or link verification to the lab’s database
Vendors who meet all six criteria are rare. In our vendor assessments, we evaluate transparency on exactly these metrics.
The Vendor Testing Spectrum
Based on our research, vendors fall into roughly four tiers:
Tier 1 — Verified Independent Testing: Named third-party lab, batch-specific COAs, QR verification, full analytical suite. Examples from our database: Science.bio (now closed) set this standard.
Tier 2 — Claims Independent Testing, Partial Verification: Says they use third-party testing, but lab isn’t named, COAs aren’t batch-specific, or verification links are absent. Most “reputable” grey-market vendors fall here.
Tier 3 — Manufacturer COAs Only: Provides documentation from the synthesis company (usually Chinese), not an independent lab. This is the minimum — better than nothing, but the testing entity has a financial interest in the product passing.
Tier 4 — No Documentation: No COAs available or provided on request. At this tier, you have zero information about what you’re injecting.
What Consumers Can Do
Request COAs before purchasing: If a vendor won’t provide batch-specific analytical data, that tells you something.
Verify independently: Services like Janoshik allow individual consumers to submit samples for testing ($100–350). For injectable products especially, this is a worthwhile investment.
Look for QR-verified COAs: These link to lab databases and can’t be easily fabricated.
Be skeptical of purity claims without documentation: “99% pure” is a marketing claim without a COA to back it up.
Understand that price doesn’t guarantee quality: Some of the most expensive vendors in our database have the weakest transparency scores.
PeptideExaminer does not endorse the use of grey-market peptides. The quality data presented here should inform risk assessment, not serve as a buying guide. The safest peptides are those produced under pharmaceutical-grade conditions with full regulatory oversight — which, for most popular peptides, currently means they aren’t legally available.
Quality statistics cited in this article come from Rohrbough Drug Testing Analysis (2020), USADA anti-doping testing data (2017), and Finnrick Analytics aggregate reports. Individual vendor quality assessments are based on our independent evaluation methodology documented on our methodology page. We did not receive compensation from any testing laboratory mentioned in this article.
This article will be updated as new testing data becomes available. Last reviewed: February 20, 2026.