P21 lab reports
What the P21 record shows
Evidence through 2026-09-29TitrateLab tracks 17 published P21 certificate-of-analysis source records through 2026-09-29, each with a recorded purity or measured-versus-label amount result. Across 17 records with a numeric peptide-purity result, including zero, the median reported purity is 99.1%. Across 13 records with measured-versus-label dose data, 31% are within 10% of the labeled quantity. This is a public convenience sample, not a randomized market survey; one result describes one submitted sample and does not verify other batches.
Published records with a non-null purity or measured-versus-label amount result. Matching uses a normalized compound slug. No deduplication in this archive summary; relays and corrected records can remain separate. Records with neither measurement are excluded here, but can appear in the research overview's exact-token raw-record total. These are not unique certificates or batches. TitrateLab indexes reports from third-party laboratories.
Aggregate calculated: 2026-10-09T20:53:27.188560+00:00. Calculation time is not a test date.
Limits and missing evidence
- The testing laboratory is unattributed on 2 records.
- Coverage depends on reports that were published and available to ingest.
P21 lab-testing metrics
COAs per testing lab
Every lab testing P21 in the corpus.
Tested-purity distribution
Bins below 90% tested purity (0% of numeric purity records).
| Purity range | Certificates |
|---|---|
| 0–50% | 0 |
| 50–70% | 0 |
| 70–80% | 0 |
| 80–85% | 0 |
| 85–90% | 0 |
| 90–91% | 0 |
| 91–92% | 0 |
| 92–93% | 0 |
| 93–94% | 0 |
| 94–95% | 0 |
| 95–96% | 0 |
| 96–97% | 0 |
| 97–98% | 0 |
| 98–99% | 3 |
| 99–100% | 14 |
COAs over time
P21 source records by test month (discovery month when test date is absent).
| Month | Certificates |
|---|---|
| 2025-10 | 1 |
| 2025-11 | 1 |
| 2026-03 | 1 |
| 2026-05 | 2 |
| 2026-06 | 2 |
| 2026-07 | 2 |
| 2026-08 | 2 |
| 2026-09 | 6 |
Most-tested vendors
Top 10 of 13 vendors by P21 certificate count.
Lab evidence
Free previewExplore this vendor’s lab reports
Pick a compound, then a report, to see what the lab measured. Each report counts once, and only reports with a source link and a readable result appear here, so this list can hold fewer reports than the total above.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free previewExplore this vendor’s lab reports
Pick a compound, then a report, to see what the lab measured. Each report counts once, and only reports with a source link and a readable result appear here, so this list can hold fewer reports than the total above.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free previewExplore this vendor’s lab reports
Pick a compound, then a report, to see what the lab measured. Each report counts once, and only reports with a source link and a readable result appear here, so this list can hold fewer reports than the total above.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free previewExplore this vendor’s lab reports
Pick a compound, then a report, to see what the lab measured. Each report counts once, and only reports with a source link and a readable result appear here, so this list can hold fewer reports than the total above.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
Lab evidence
Free preview1 lab reports from this vendor
This chart compares report counts for this compound. A larger test history does not establish better purity, dose accuracy or endotoxin results. Inspect the individual reports to compare measurements.
Pro shows the vendor’s name, its original lab reports and batch details.
- Vendor names on every ranking and chart
- Original COAs with batch details
- Buyer reviews for each vendor
- Price and stock alerts for your watchlist
- Ask Titer, the AI research assistant
Monthly or yearly plans. Cancel either anytime. Compare plans
+ 3 more vendors with fewer certificates.
Published P21 certificates of analysis
Open all 17 P21 reports.
Unlock the actual vendor, purity, dose accuracy, lab, batch and saved certificate for every P21 result.
Unlock P21 reportsPro · $14/month or $88/year
Illustrative structure only. No record-level values are present in this preview.
Reading P21 lab reports
A valid report describes the sample that was submitted, not every vial sold under the same name. Guide: How to verify and read a peptide COA: 5 checks.