Research library / Guides
Purity and measured content across every report we have published.
Across 149 published lab reports on 25 Prism Labs peptides, tested between April 8, 2026 and October 26, 2026, purity ranged from 99.01% to 99.94%, with a median of 99.60%. Measured content ranged from 96% to 129% of the label, with a median of 102%.
Side by side
| Detail | RETA (GLP-3) | TIRZ (GLP-2) | MOTS-c |
|---|---|---|---|
| Format | Lyophilized vial | Lyophilized vial | Lyophilized vial |
| Listed sizes | 20mg · 30mg | 20mg · 40mg | 10mg · 20mg · 40mg |
| Price | $124.99 to $149.99 per vial | $69.99 to $99 per vial | $39.99 to $109.99 per vial |
| Availability | In stock | In stock | In stock |
| Reported purity | 99.43% | 99.14% | 99.12% |
| Latest batch report | October 26, 2026 · lot 497799 | October 26, 2026 · lot 837797 | October 26, 2026 · lot 368304 |
| Reference formula | C221H342N46O68 | C225H348N48O68 | C101H152N28O22S2 |
| Reference weight | 4731 g/mol | 4813 g/mol | 2174.6 g/mol |
| Reference sequence | — | — | H-MRWQEMGYIFYPRKLR-OH |
| Reference CAS number | — | — | 1627580-64-6 |
Catalog figures, current at page load. Published batch reports cover past lots and do not name the lot a new order ships with.
RETA (GLP-3), TIRZ (GLP-2) and MOTS-c — how much does each cost?
RETA (GLP-3): $124.99 to $149.99 per vial. TIRZ (GLP-2): $69.99 to $99 per vial. MOTS-c: $39.99 to $109.99 per vial. Packs discount every vial in the order: 2 vials 5% off, 3 vials 10% off, 5 vials 14% off, 10 or more vials 18% off. Free standard shipping on orders over $125.
Where to buy RETA (GLP-3), TIRZ (GLP-2) and MOTS-c
All are for sale direct from Prism Labs, USA made, with the batch Certificate of Analysis published on each product page. Orders placed before 4:30 PM CT ship the same day, seven days a week, when inventory is available.
RETA (GLP-3), TIRZ (GLP-2) and MOTS-c — are they in stock?
RETA (GLP-3): in stock. TIRZ (GLP-2): in stock. MOTS-c: in stock. Each product page carries live availability.
01
The findings
Each figure below comes from the reports published on our Quality page:
- 149 reports cover 96 lots of 25 peptides.
- No report measured purity below 99%. The lowest result was 99.01%.
- 15 of 149 reports measured less than the labeled amount, and none measured below 95% of the label.
- The highest content result was 129% of the label, so a vial can also hold more than it states.
02
What the purity figure means
Purity is the share of the measured material that is the target peptide. The rest is mostly related impurities from synthesis, such as shortened or altered peptide chains.
A purity result does not say how many milligrams are in the vial. That is what the content result is for.
Sources: [1] Journal of Pharmaceutical and Biomedical Analysis · 2014
03
What the content figure means
Content is the amount the lab measured, set against the label. We report it here as a percent of the label: 102% is the median, so the typical vial tested a little above its stated amount.
Peptides are usually supplied as salts, and counter-ions from purification stay with the peptide, so a content figure depends on how the lab reports it. Compare results of the same kind, and read the method on the report.
Sources: [2] Pharmaceutics · 2019
04
Results by compound
The table shows the full range for each compound, across every report published for it.
Published lab results by compound
| Compound | Reports | Purity | Measured content, % of label |
|---|---|---|---|
| RETA (GLP-3) | 13 | 99.19–99.93% | 100–104% |
| TIRZ (GLP-2) | 4 | 99.14–99.85% | 102–107% |
| MOTS-c | 8 | 99.05–99.84% | 101–108% |
| Tesamorelin | 7 | 99.03–99.83% | 101–105% |
| Sermorelin | 2 | 99.53–99.83% | 102–107% |
| GHK-Cu | 14 | 99.21–99.87% | 97–108% |
| Glow-70 | 7 | 99.14–99.82% | 100–104% |
| Klow-80 | 6 | 99.18–99.86% | 102–104% |
| Glutathione | 5 | 99.11–99.82% | 100–101% |
| Melanotan II (MT-2) | 2 | 99.24–99.86% | 102–105% |
| CJC / Ipamorelin (No DAC) | 6 | 99.53–99.83% | 102–112% |
| BPC-157 | 11 | 99.15–99.94% | 100–129% |
| NAD+ | 8 | 99.05–99.89% | 100–104% |
| DSIP | 4 | 99.21–99.83% | 101–109% |
| Selank | 7 | 99.24–99.91% | 99–117% |
| Semax | 7 | 99.13–99.86% | 96–114% |
| TB-500 | 8 | 99.15–99.86% | 101–119% |
| Ipamorelin | 4 | 99.35–99.87% | 100–107% |
| SS-31 | 4 | 99.27–99.81% | 99–110% |
| KPV | 4 | 99.21–99.82% | 100–107% |
| Epitalon | 4 | 99.09–99.83% | 104–114% |
| Thymosin Alpha-1 | 4 | 99.31–99.78% | 101–114% |
| PT-141 | 4 | 99.38–99.82% | 101–113% |
| 5-amino-1MQ | 4 | 99.01–99.86% | 100–105% |
| AOD-9604 | 2 | 99.48–99.84% | 102–114% |
Computed from the reports published at page load. Past lots only; these results do not name the lot a new order ships with.
05
How these numbers were worked out
The figures update when a report is published, using these rules:
- Every published report on a peptide currently in the catalog counts once. A lot tested twice counts twice.
- Content is the measured amount divided by the labeled amount. For blends, that is the measured total against the labeled total.
- Water is left out, because it carries no peptide purity or content result.
- Reports come from independent third-party labs. We change labs over time, and each report names the lab that issued it.
06
What this data cannot show
Read these results for what they are:
- We chose and sent the samples, so this is our own record and not an independent audit of the market.
- A report covers the lot it tested. These figures do not name the lot a new order ships with, so match your vial's lot to its report.
- This page covers purity and content only. Any other result is listed on the individual report.
- Different labs and methods can give somewhat different results, so small gaps between reports may not mean much.
Browse every report and find your lot
·
A little more clarity
Questions, answered
Did any report come in under 99% purity?
No. The lowest purity across 149 published reports was 99.01%.
Did any vial measure less than its label?
Yes. 15 of 149 reports measured below the labeled amount. The lowest was 96% of the label.
Who tested these lots?
Independent third-party labs. We change labs over time, and each report names the lab that issued it.
Can I check a report myself?
Yes. Every report is listed on our Quality page with its lot number, test date and a link to open it.
Are these peptides for human use?
No. Prism Labs sells them for laboratory research use only.
Follow the evidence
Sources & reading notes
Open the original record for its methods and limitations. The sources below do not certify the supplied product or its finished formulation.
- Journal of Pharmaceutical and Biomedical Analysis · 2014 ↗
Review of the impurities that arise in synthetic peptides.
- Pharmaceutics · 2019 ↗
How counter-ions such as acetate and trifluoroacetate stay with purified peptides.
Prepared by Prism Labs from the linked source records and public product documentation. Research context only; not a preparation protocol or a claim about outcomes. Send a source correction.
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