The State of Research Peptide Quality. 2026.
An independent dataset from 30500 research peptide samples submitted to Apollo Analytical between Jan 2025 and Dec 2025 — across 195 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 2025 dataset.
Roughly 1 in 3 vials fail at least one release specification.
Across 30,500 independently submitted samples, 31% failed identity, purity, content, or microbial specifications. The headline pass rate is higher than 2024 (58%) and 2025 (62%), but the underlying failure modes are unchanged.
Under-fill is now the dominant defect, not purity.
Of failing samples, the most common single defect was a stated-mass shortfall greater than 10%. Vials labeled '10 mg' commonly assayed at 6.5–8.5 mg. This pattern was concentrated in lyophilized fills sourced from a handful of repeat suppliers.
GLP-1 quality is improving — slowly.
Semaglutide / Tirzepatide / Retatrutide samples passed at 74% in 2025, up from 61% in 2024 and 55% in 2023. Identity failures dropped sharply; under-fill did not.
Reference standards still matter more than supplier reputation.
Failure rate did not correlate with brand recognition or price. Samples from boutique suppliers passed at the same rate as samples from high-volume vendors when reference standards were used.
How peptides actually fail.
A failing sample frequently fails more than one specification. Percentages below are share of all 30500 samples submitted, not share of failing samples.
| Failure mode | % of samples | What we typically see |
|---|---|---|
| Under-fill of stated mass (>10% short) | 18% | Most common failure. Worst in compounded vials labeled 5–10 mg. |
| HPLC purity below stated spec (>2% gap) | 14% | Truncation impurities dominate long GHRH analogs and stapled peptides. |
| Identity mismatch by ESI-MS | 11% | Most often deamidation, oxidation, or — in ~280 cases — entirely different peptide than labeled. |
| Excess residual TFA (>1%) | 7% | Linked to cytotoxicity in downstream assays. Easily caught with ion chromatography. |
| Endotoxin above injectable threshold | 4% | Subset (n≈9,000 tested for LAL). Compounded sterile-fill products dominated failures. |
| Water content out of spec (Karl Fischer) | 3% | Often a packaging / storage issue, not a synthesis defect. |
How the dataset was built.
Every sample in this report was submitted by an independent third party (researcher, compounding pharmacy, or vendor QC), tested under our standard release panel, and reviewed by the same analyst pair. No supplier or client paid to be included or excluded.
Cite this report.
This dataset is released under Creative Commons Attribution 4.0. Republish, embed, or quote with a link back to this page.
Retrieved from https://apolloanalytical.com/peptide-quality-report-2026