Prime Peptides vs S1Research
Two top US peptide sources scored on the identical published formula: lab credibility, shipping, pricing, operating history, and transparency.
- Prime Peptides
- 7.94/10
Prime Peptides
- S1Research
- 7.75/10
S1Research
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Factor by factor
- 8.6Lab Credibilityweight 55%8.7
- 9.0Shipping & Refundweight 20%6.0
- 6.3Pricingweight 15%9.5
- 3.8Operating Historyweight 5%1.8
- 5.5Transparencyweight 5%5.0
- 20Certificates confirmed at the lab29
- 5Labs named on certificates2
Show as a table
| Category | Prime Peptides | S1Research |
|---|---|---|
| Lab Credibility | 8.6 | 8.7 |
| Shipping & Refund | 9.0 | 6.0 |
| Pricing | 6.3 | 9.5 |
| Operating History | 3.8 | 1.8 |
| Transparency | 5.5 | 5.0 |
| Overall | 7.94 | 7.75 |
Products both carry, price for price
| Peptide | Prime Peptidesper unit | S1Researchper unit |
|---|---|---|
| BPC-157Guide → | $5.50/mg | $2.00/mg |
| TB-500Guide → | $6.50/mg | $3.60/mg |
| GHK-CuGuide → | $0.60/mg | $0.31/mg |
| IpamorelinGuide → | $6.00/mg | $2.60/mg |
| Semax | $4.50/mg | $3.50/mg |
| Sermorelin | $7.00/mg | $3.70/mg |
| Tesamorelin | $8.00/mg | $2.35/mg |
| RetatrutideGuide → | $5.42/mg | $1.50/mg |
| TirzepatideGuide → | $4.33/mg | $1.00/mg |
| SemaglutideGuide → | $7.50/mg | $1.50/mg |
| AOD-9604 | $12.00/mg | — |
| BPC-157 + TB-500 | $6.25/mg | $2.50/mg |
| Bacteriostatic Water | $2.50/mL | — |
| CJC-1295 + Ipamorelin | $8.00/mg | $2.70/mg |
| MOTS-c | $6.00/mg | $1.30/mg |
| Glutathione | $0.05/mg | $0.02/mg |
| NAD+ | $0.14/mg | $0.06/mg |
| KLOW | $1.81/mg | $0.62/mg |
| GLOW | $1.86/mg | $0.60/mg |
How they compare: the verdict
Prime Peptides takes this matchup by a razor-thin margin, 7.94 to 7.75 on the published formula. Its biggest edge is shipping & refunds, where it scores 9.0 against S1Research's 6.0.
It isn't a clean sweep. S1Research actually edges ahead on pricing (9.5 vs 6.3), so if that factor matters most to you it's worth weighing.
On lab evidence, the heaviest-weighted factor, both Prime Peptides and S1Research have independently verified third-party COAs, so the gap comes down to the other categories.
Across the 17 peptides both carry, S1Research is cheaper per unit more often (Prime Peptides wins on 0, S1Research on 17). The price-for-price table below has the detail, per mg (or per IU or mL for products sold that way).
Prime Peptides vs S1Research: FAQ
Prime Peptides or S1Research: which is better?
Prime Peptides takes this matchup by a razor-thin margin, 7.94 to 7.75 on the published formula. Its biggest edge is shipping & refunds, where it scores 9.0 against S1Research's 6.0. It isn't a clean sweep. S1Research actually edges ahead on pricing (9.5 vs 6.3), so if that factor matters most to you it's worth weighing. On lab evidence, the heaviest-weighted factor, both Prime Peptides and S1Research have independently verified third-party COAs, so the gap comes down to the other categories. Across the 17 peptides both carry, S1Research is cheaper per unit more often (Prime Peptides wins on 0, S1Research on 17). The price-for-price table below has the detail, per mg (or per IU or mL for products sold that way).
Do Prime Peptides and S1Research both use third-party testing?
Prime Peptides: independently verified third-party COAs. S1Research: independently verified third-party COAs.
How was this comparison scored?
Both vendors are scored on the identical published formula: lab credibility 55%, shipping 20%, pricing 15%, operating history 5%, transparency 5%. When third-party testing cannot be independently verified, a testing gate holds the score under a cap that starts at 6.0 and rises by at most 2.5 points for operating history, shipping and reviews. Neither vendor can pay to change a score.
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