Every quarter, PeptideWatchdog compiles a transparency report summarizing trends we observe across our vendor testing program. This Q4 2025 report covers October through December and reflects testing across our ranked vendor portfolio.
Overall Quality Trends
The average HPLC purity across all vendors tested in Q4 came in at 97.3%, a slight improvement over Q3's 96.8%. This upward trend has been consistent throughout 2025, suggesting that vendor awareness of third-party testing is having a positive effect on quality standards across the industry.
Identity confirmation rates held steady at 98.2% across all peptides tested. The small number of identity failures were concentrated in complex peptides with 30+ residues, where synthesis challenges make errors more likely.
Grade Distribution
Of the vendors with published grades at the end of Q4, the distribution breaks down as follows: Platinum-grade vendors represent 12% of the ranked pool, Gold sits at 34%, Silver at 38%, and Bronze at 16%. No active vendors currently fall below Bronze, as those that scored in the ungraded range have either improved or been delisted.
The Platinum tier saw one new entrant this quarter, bringing the total to its highest level since we began tracking. Two vendors moved from Silver to Gold after improving their COA documentation and sterility testing practices.
COA Accuracy
COA accuracy remains the weakest category across the vendor landscape. The average deviation between vendor-claimed purity and our independently measured purity was 1.8 percentage points. While this is within a reasonable range, several vendors showed deviations above 3%, which we consider a red flag for quality control consistency.
Notably, vendors in the Gold and Platinum tiers showed an average deviation of only 0.9%, while Silver and Bronze vendors averaged 2.7%. This correlation between overall quality and COA honesty reinforces a pattern we have observed since launch: the best vendors are also the most transparent.
Sterility Testing
Endotoxin testing compliance improved significantly in Q4. Of vendors who offer products marketed for research involving injection protocols, 71% now provide sterility data on their COAs, up from 58% in Q3. This is largely driven by vendor submissions to our testing program, where sterility is a scored component.
Of those tested, 94% met acceptable endotoxin thresholds (below 0.5 EU/mg). The failures were concentrated in two vendors who have since been notified and are implementing corrective measures.
Mystery Purchase Results
PeptideWatchdog conducts unannounced mystery purchases each quarter to supplement vendor-submitted samples. These purchases simulate the actual customer experience and remove any possibility that vendors send specially prepared samples for testing.
In Q4, mystery purchases showed an average 0.4% lower purity compared to vendor-submitted samples from the same companies. This gap has narrowed from 1.1% when we began the mystery purchase program, suggesting that vendors are maintaining more consistent quality rather than cherry-picking their best batches for submission.
Community Testing
Our community-funded testing initiative processed 23 tests in Q4, contributed by community members who wanted specific vendors or peptides evaluated. These tests follow the same laboratory protocols as our standard testing and results are published in the same format.
Community-submitted samples showed quality patterns consistent with our own purchases, with an average purity of 96.9%. One community test revealed a previously undetected identity issue with a lesser-known vendor, which led to an immediate investigation and subsequent downgrade.
Looking Ahead to Q1 2026
For Q1, we are expanding our tested peptide catalog to include several newer compounds that have gained significant research interest. We are also piloting a label compliance audit that will evaluate vendor packaging and labeling practices, which will become part of our scoring methodology.
Our goal remains the same: provide the research community with objective, verifiable data so you can make purchasing decisions based on evidence rather than marketing claims. If you have vendors or peptides you would like to see tested, submit a request through our community testing program.