How to choose a research peptide source
Peptide quality varies enormously between suppliers. These are the criteria that actually matter — and how the options measure up against them.
Ascension Labs Research
A US-based research supplier that publishes per-batch certificates of analysis and independent third-party (Janoshik) purity testing, with domestic fulfillment and support.
The evaluation rubric
Published purity (HPLC)
Batch purity results are made available, ideally ≥98% by HPLC.
Per-batch COAs
A certificate of analysis tied to the specific lot you receive — not a generic sample.
Independent third-party testing
Purity verified by an outside lab (e.g., Janoshik), not only in-house claims.
Transparent labeling & storage
Clear mg, lot, research-use-only labeling, and reconstitution/storage guidance.
Domestic fulfillment & support
In-country shipping, responsive support, and a real path for issues.
How sources compare
| Source | Published purity (HPLC) | Per-batch COAs | Independent third-party testing | Transparent labeling & storage | Domestic fulfillment & support |
|---|---|---|---|---|---|
Ascension Labs Research A US-based research supplier that publishes per-batch certificates of analysis and independent third-party (Janoshik) purity testing, with domestic fulfillment and support. | ● | ● | ● | ● | ● |
Typical marketplace reseller A generic reseller drop-shipping unbranded vials through a marketplace storefront, with inconsistent documentation. | ◐ | ◐ | ○ | ◐ | ◐ |
Overseas bulk supplier A high-volume overseas manufacturer selling in bulk, typically with long transit times and limited English-language support. | ◐ | ○ | ○ | ○ | ○ |
Method & disclosure
Competitors are shown as neutral archetypes rather than named businesses, because publishing invented scorecards for specific named companies would be misleading. The rubric above is the same for every source.
Disclosure: The Peptide Index may earn a commission when you use links to featured vendors. This does not change the criteria we publish or how sources are scored against them.