The State of Research Peptide Quality. 2025.
An independent dataset from 25000 research peptide samples submitted to Apollo Analytical during Jan 2024 – Dec 2024 — across 168 distinct suppliers. Free to share, cite, and republish with attribution.
Pass rate by peptide class
Percent of samples meeting all release specifications (identity, purity, content, residuals). n shown per class.
Four conclusions from the 2024 dataset.
Pass rate climbed to 62% — a 4-point improvement over 2023.
Across 25,000 independently submitted samples, the overall pass rate rose meaningfully year-over-year, mostly on the back of fewer identity failures.
Under-fill overtook purity as the #1 defect.
For the first time in our dataset, stated-mass shortfalls beat HPLC purity gaps. Lyophilized fills from repeat suppliers were the worst offenders.
GLP-1 quality improved sharply.
Semaglutide / Tirzepatide / Retatrutide samples passed at 61%, up from 55% in 2023. Identity failures dropped notably as suppliers tightened SPPS protocols.
Independent third-party testing was still the only reliable filter.
Vendor self-reported COAs continued to over-state purity by an average of 2.7 percentage points relative to our re-analysis.
How peptides actually fail.
A failing sample frequently fails more than one specification. Percentages below are share of all 25000 samples submitted, not share of failing samples.
| Failure mode | % of samples | What we typically see |
|---|---|---|
| Under-fill of stated mass (>10% short) | 20% | Took over as the #1 defect — pulling away from purity as labs cleaned up SPPS workflows. |
| HPLC purity below stated spec (>2% gap) | 17% | Truncation impurities still dominant in long GHRH analogs. |
| Identity mismatch by ESI-MS | 14% | Deamidation and oxidation; ~390 cases were entirely different peptide than labeled. |
| Excess residual TFA (>1%) | 8% | Linked to cytotoxicity in downstream assays. |
| Endotoxin above injectable threshold | 5% | Subset (n≈7,100 tested for LAL). Compounded sterile-fill products dominated failures. |
| Water content out of spec (Karl Fischer) | 4% | Often a packaging / storage issue, not a synthesis defect. |
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