The State of Research Peptide Quality. 2024.
An independent dataset from 20000 research peptide samples submitted to Apollo Analytical during Jan 2023 – Dec 2023 — across 142 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 2023 dataset.
Less than 6 in 10 vials passed all release specs.
Across 20,000 independently submitted samples, 42% failed identity, purity, content, or microbial specifications — a baseline we've tracked improving in subsequent years.
Purity was the dominant failure mode.
HPLC gap from labeled spec was the most common single defect in 2023, driven heavily by GHRH analogs and longer sequences with truncation impurities.
GLP-1 quality was alarmingly inconsistent.
Semaglutide and Tirzepatide samples passed at only 55%. Identity failures (deamidation, wrong sequence) drove most rejections.
Brand reputation was a poor predictor.
High-profile vendors failed at similar rates to boutique suppliers. Reference-standard-backed identity testing was the only reliable filter.
How peptides actually fail.
A failing sample frequently fails more than one specification. Percentages below are share of all 20000 samples submitted, not share of failing samples.
| Failure mode | % of samples | What we typically see |
|---|---|---|
| HPLC purity below stated spec (>2% gap) | 19% | Truncation impurities dominated long GHRH analogs and stapled peptides. |
| Under-fill of stated mass (>10% short) | 22% | Particularly bad in compounded vials labeled 5–10 mg. |
| Identity mismatch by ESI-MS | 16% | Frequent deamidation and oxidation; ~480 samples were entirely wrong peptide. |
| Excess residual TFA (>1%) | 9% | Linked to cytotoxicity in downstream assays. |
| Endotoxin above injectable threshold | 6% | Subset (n≈5,400 tested for LAL). Compounded sterile-fill products dominated. |
| Water content out of spec (Karl Fischer) | 4% | Often a packaging / storage issue, not a synthesis defect. |
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