Value analysis
Does paying more buy better peptides?
No — and the data points the other way. Across 33 vendors the correlation between price and evidence score is -0.74, a strong inverse relationship: in this index the cheaper vendors document their testing markedly better, not worse. Vendors priced below the market median average 79.2 on the evidence rubric; those at or above it average 66.5, a gap of 12.7 points in the cheaper vendors' favour. Paying above the market does not buy better paperwork here, and on this evidence it tends to buy less. Price index below is the vendor's own prices as a percentage of the median across every vendor we price for the same compounds, so 100 is the market and 85 is fifteen percent under it.
33 vendors with both a price index and a score · correlation -0.74 · 627 certificates behind the scores
Best value: under the market, still documented
| Vendor | Score | Price vs market | Certificates |
|---|---|---|---|
 Origin Labs | 89.1 | -43% | 25 |
 Next Gen Peptides | 87.7 | -40% | 114 |
 ZC Labs | 87.2 | -58% | 39 |
 Amino Club | 86.1 | -25% | 23 |
 PeptidePlugs | 82.6 | -17% | 70 |
 Modern Aminos | 79.7 | -1% | 30 |
The rule, stated so you can disagree with it: priced under the peer median, and holding at least 3 certificates from a named laboratory. Ordered by score.
Every vendor, cheapest first
| Vendor | Price index | vs market | Evidence score | Certificates |
|---|---|---|---|---|
| ZC Labs | 42.2 | -58% | 87.2 | 39 |
| Origin Labs | 57.1 | -43% | 89.1 | 25 |
| Next Gen Peptides | 60.4 | -40% | 87.7 | 114 |
| EPEternal Peptides | 70.7 | -29% | 66 | 0 |
 Hydro Research Peptides | 73.3 | -27% | 78.7 | 21 |
| Amino Club | 75.0 | -25% | 86.1 | 23 |
 Transition Biotech | 82.6 | -17% | 74.3 | 7 |
| PeptidePlugs | 83.3 | -17% | 82.6 | 70 |
| GSGood Science Bio | 83.3 | -17% | 69.2 | 0 |
 Evo Labs Research | 95.0 | -5% | 71.9 | 1 |
 One Aminos | 95.5 | -5% | 78 | 27 |
| Modern Aminos | 99.2 | -1% | 79.7 | 30 |
 Stealth Research Labs | 100.0 | +0% | 78.1 | 10 |
 Simple Peptide | 100.0 | +0% | 77.2 | 29 |
 Koi Peptides | 100.0 | +0% | 75.1 | 6 |
 Prime Peptides | 100.0 | +0% | 74.4 | 9 |
| TRTrue Research Labs | 100.0 | +0% | 62.7 | 0 |
| MHMile High Compounds | 100.0 | +0% | 59.2 | 0 |
 Bench Grade Peptides | 100.2 | +0% | 79.4 | 53 |
| GPGenX Peptides | 104.5 | +5% | 63.4 | 0 |
| EPEvolve Peptides | 106.9 | +7% | 62.5 | 0 |
 NeuroLabs Research | 109.1 | +9% | 74.6 | 14 |
| BPBiotech Peptides | 109.5 | +10% | 59.1 | 0 |
 Ascension Peptides | 112.7 | +13% | 74.4 | 33 |
 Protide Health | 122.1 | +22% | 72.8 | 3 |
| EPExtreme Peptides | 136.3 | +36% | 57.4 | 0 |
| IPImproved Peptides | 140.0 | +40% | 58.6 | 1 |
 Curo | 146.8 | +47% | 73.9 | 17 |
| BLBioLongevity Labs | 147.5 | +48% | 57.7 | 0 |
| NLNorthline Labs | 152.4 | +52% | 68 | 33 |
| VLVertex Labs | 155.5 | +56% | 55.4 | 21 |
| LPLicensed Peptides | 160.8 | +61% | 61.4 | 15 |
| STSports Technology Labs | 174.1 | +74% | 50.7 | 0 |
Priced above the market, thinly evidenced
These vendors charge at least ten percent over the peer median while scoring at the bottom of the priced set. That combination is the one with no argument behind it: Sports Technology Labs (50.7, +74%), Vertex Labs (55.4, +56%), Extreme Peptides (57.4, +36%), BioLongevity Labs (57.7, +48%), Improved Peptides (58.6, +40%). A high price may buy faster shipping or better support, neither of which this index measures. It does not appear to buy better documentation.
What this does and does not measure
The price index compares a vendor against its peers on the compounds both sell, so vial sizes and catalogue mix do not distort it. It is built from prices captured on the vendor’s own store, and each figure carries the date it was read.
The evidence score measures documentation: third-party certificates, the laboratory behind them, the gap between labelled and assayed mass, and business transparency. It does not measure shipping speed, customer service, or how a compound performs, and it is not a safety judgement.
Correlation is not causation, and 33 vendors is a small sample. The honest reading is the weaker one: price is not a reliable signal of documentation quality, so it should not be used as a shortcut for one. The rubric is published in full.