S1Research vs Zeptix Labs
Two top US peptide sources scored on the identical published formula: lab credibility, shipping, pricing, operating history, and transparency.
- S1Research
- 7.75/10
S1Research
- Zeptix Labs
- 8.17/10
Zeptix Labs
Affiliate links: we may earn a commission if you buy. It never changes a score or rank.
Factor by factor
- 8.7Lab Credibilityweight 55%8.2
- 6.0Shipping & Refundweight 20%10.0
- 9.5Pricingweight 15%8.8
- 1.8Operating Historyweight 5%1.3
- 5.0Transparencyweight 5%5.5
- 29Certificates confirmed at the lab18
- 2Labs named on certificates2
Show as a table
| Category | S1Research | Zeptix Labs |
|---|---|---|
| Lab Credibility | 8.7 | 8.2 |
| Shipping & Refund | 6.0 | 10.0 |
| Pricing | 9.5 | 8.8 |
| Operating History | 1.8 | 1.3 |
| Transparency | 5.0 | 5.5 |
| Overall | 7.75 | 8.17 |
Products both carry, price for price
| Peptide | S1Researchper unit | Zeptix Labsper unit |
|---|---|---|
| BPC-157Guide → | $2.00/mg | $3.00/mg |
| Cagrilintide | $4.40/mg | $10.00/mg |
| CJC-1295 + Ipamorelin | $2.70/mg | $8.00/mg |
| Epitalon | $2.50/mg | $3.00/mg |
| GHK-CuGuide → | $0.31/mg | $0.40/mg |
| GLOW | $0.60/mg | $1.71/mg |
| IpamorelinGuide → | $2.60/mg | $6.00/mg |
| KLOW | $0.62/mg | $0.81/mg |
| MOTS-c | $1.30/mg | $3.00/mg |
| PT-141 | $2.00/mg | $4.50/mg |
| RetatrutideGuide → | $1.50/mg | $2.67/mg |
| SemaglutideGuide → | $1.50/mg | $7.00/mg |
| Sermorelin | $3.70/mg | $7.00/mg |
| TB-500Guide → | $3.60/mg | $9.50/mg |
| BPC-157 + TB-500 | $2.50/mg | $5.00/mg |
| Tesamorelin | $2.35/mg | $5.00/mg |
| TirzepatideGuide → | $1.00/mg | $3.67/mg |
| Bacteriostatic Water | — | $2.00/mL |
How they compare: the verdict
Zeptix Labs takes this matchup by a clear margin, 8.17 to 7.75 on the published formula. Its biggest edge is shipping & refunds, where it scores 10.0 against S1Research's 6.0.
It isn't a clean sweep. S1Research actually edges ahead on pricing (9.5 vs 8.8), so if that factor matters most to you it's worth weighing.
On lab evidence, the heaviest-weighted factor, both S1Research and Zeptix Labs 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 (S1Research wins on 17, Zeptix Labs on 0). The price-for-price table below has the detail, per mg (or per IU or mL for products sold that way).
Affiliate links: we may earn a commission if you buy. It never changes a score or rank.
S1Research vs Zeptix Labs: FAQ
S1Research or Zeptix Labs: which is better?
Zeptix Labs takes this matchup by a clear margin, 8.17 to 7.75 on the published formula. Its biggest edge is shipping & refunds, where it scores 10.0 against S1Research's 6.0. It isn't a clean sweep. S1Research actually edges ahead on pricing (9.5 vs 8.8), so if that factor matters most to you it's worth weighing. On lab evidence, the heaviest-weighted factor, both S1Research and Zeptix Labs 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 (S1Research wins on 17, Zeptix Labs on 0). The price-for-price table below has the detail, per mg (or per IU or mL for products sold that way).
Do S1Research and Zeptix Labs both use third-party testing?
S1Research: independently verified third-party COAs. Zeptix Labs: 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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