Vial Verdict
Honest reviews of research peptide suppliers.
We score every supplier on the same five criteria: purity-data transparency, Certificate of Analysis per lot, shipping practices, customer support, and refund policy. The methodology is public; the scores aren't editable by suppliers.
Current rankings — 1 supplier published
The rubric
How we score.
Five categories, fixed weights. Reflects how often each one actually breaks for buyers — not what's easiest to evaluate. Scores are independent of any commercial relationship with the supplier.
Read the full methodology →What we look for
Eight markers of a reference-grade supplier.
Every supplier in this register is scored against these markers. Hit them and you score well. Miss them and you don't.
- Per-lot COA published openly
Not "available on request." The COA appears on the product page with the lot number.
- HPLC chromatogram attached
A purity number with no underlying chromatogram is unverifiable marketing copy.
- Mass-spec identity confirmation
Theoretical vs observed molecular weight, within ~1 Da.
- Counter-ion identity stated
TFA salt, acetate, or HCl. Affects solubility and assay compatibility.
- Peptide content (%) reported
Net peptide mass vs gross vial mass. Critical for concentration-sensitive work.
- Endotoxin + bioburden figures
Required for cell-culture and animal-model research-grade material.
- Unique lot number on the vial
The audit trail between physical material and the COA.
- Refund policy in writing on the site
Not negotiated case-by-case after the fact.
Red flags
Five behaviors that should stop your purchase.
Not warning signs — disqualifying. If you see any of these, walk before placing the order. The full list runs to ten.
- 01
Purity claim with no chromatogram
Marketing copy. Reference suppliers publish the trace.
- 02
Same COA across multiple lots
They're producing decorative documents, not testing.
- 03
Stock-photo chromatograms
Reverse-image-search any chromatogram you're skeptical of.
- 04
"COA on request"
Behind industry practice at best. Buying time at worst.
- 05
No batch number on the vial
Without a lot number, you can't match the COA to the material.
Browse by purchase context
Best for the question you're actually asking.
Different research questions weight the rubric differently. These category pages re-rank the supplier register against a specific purchase context.
HPLC chromatograms, per-lot COAs, mass-spec data published openly.
Open ranking →
Suppliers that hit acceptable documentation at the most-accessible tiers.
Open ranking →
Cold-chain shipping and multi-currency invoicing across borders.
Open ranking →
The widest catalog of research peptides under a single supplier.
Open ranking →
Common questions
Before you trust the rankings.
- How are scores calculated?
- Five categories with fixed weights: purity-data transparency (30%), Certificate of Analysis per lot (25%), shipping (15%), customer support (15%), refund policy (15%). The full rubric for each score is published on the methodology page.
- Do you accept payment to alter reviews?
- No. Scores are not adjustable by suppliers — paid or otherwise. Vial Verdict earns affiliate commissions on some outbound supplier links; the disclosure is in the footer of every page and at the top of every review. The score is independent of the commercial relationship.
- How often are reviews refreshed?
- Reviews are updated when supplier documentation practice changes materially — new COA format, new lot tracking, new shipping policy. Every review carries the date it was last reviewed at the top.
Editorial standard
Independent, methodology-driven, disclosed.
Suppliers cannot edit their scores. Scores are determined by the published rubric, applied identically across the register.
Vial Verdict earns affiliate commissions on some outbound supplier links. The disclosure is on every page footer and at the top of every review where applicable.
Compounds discussed are research reference standards. Nothing on this site constitutes medical advice or dosing guidance.