PeptideChecked evaluates research peptide suppliers on how much evidence they publish about what they sell. We don't rate effects, results or uses, and we don't cover dosing or human use.
Notice: Research peptides are sold for in-vitro laboratory research only. They are not FDA-approved and not for human or animal consumption. Nothing on this site is medical, legal or purchasing advice.
What we do and don't do
- We don't buy, handle or test products. Our analysis is based on public documents only.
- We cite a source for every factual claim, either inline or in the vendor's source list. When we can't verify something, we say so.
- We list GLP-1-class research compounds (for example retatrutide) when a rated vendor sells them, with the same research-use-only framing: prices and COAs only, never dosing or human-use content.
Who gets listed
Every vendor we feature had a live storefront when checked, posts COAs publicly and uses research-use-only disclaimers. We don't exclude vendors for FDA warning letters or marketing problems. We disclose them on each review and score them under "Labeling" and "Regulatory record" instead. As of September 26, 2026, one listed vendor, Swiss Chems, has an FDA warning letter (December 2024).
Two scores: overall and transparency
Each vendor shows two numbers.
- Overall score (out of 10) is our editors' rating. It's the number on vendor cards, comparison tables and the top of each review. It starts from the transparency score below and also weighs things that method doesn't measure: price, catalog range, discount codes, shipping and checkout options, and our partnership terms with the vendor.
- Transparency score comes only from the published method below. Reviews and comparisons show it separately, so you can compare vendors on documentation alone.
How we score transparency (5-10 display scale)
Every vendor is scored on six factors from public documents. Each factor is scored 0-10 and weighted as below, which gives a raw method score from 0 to 10.
| Factor | Weight | What we check |
|---|---|---|
| COA publication | 20% | Public, batch/lot-specific, dated |
| Lab traceability | 20% | Named lab; verification possible |
| Independent testing | 20% | Finnrick rating, sample count, recency |
| Labeling and naming | 20% | Strict RUO framing; compounds named, not coded; no dosing or health-style content |
| Business transparency | 10% | Address, entity, payment and shipping disclosed |
| Regulatory record | 10% | No FDA letters; no enforcement history |
Transparency scores are shown on a 5-10 scale. A 5 means a vendor just meets our minimum bar to be listed (see "Who gets listed" above), and a 10 is a perfect score on every factor. The formula is: displayed rating = 5 + half the raw 0-10 method score. For example, a raw score of 6.2 is shown as 8.1. Each factor score in a review's scoring table uses the same conversion, so the weighted average of the factors equals the rating. We round to one decimal, and exact halves are rounded down so the display never overstates the method score.
Because the scale starts at 5, a 7 here is a below-average vendor on our method, not a good one. Compare vendors by the gap between their ratings. A vendor with no independent tests gets a raw 0 on that factor, which shows as 5.0. Our reasoning is in Janoshik vs Finnrick and how to read a peptide COA.
How we order the list
The order of our vendor list is our editors' pick and follows the overall score. That means the #1 vendor may not have the highest transparency score.
- The transparency score comes only from the method above. No payment or partnership changes it, and we report COA, lab and FDA facts the same way for every vendor.
- Affiliate relationships can affect which vendors we feature, their order and their overall score. Some outbound links earn us a commission, and some codes are our partner codes.
- If you want documentation quality alone, compare transparency scores, not positions.
Freshness and corrections
Vendors in this market close or receive warning letters quickly (see the 2025-2026 timeline). Every vendor page shows a last-verified date. The current transparency scores reflect checks made on September 26, 2026 (September 28 for Licensed Peptides). Shop prices on the homepage were checked on the vendors' own stores on October 7, 2026. If something has changed or we've got it wrong, contact us with a source and we'll re-check it.
Start here: best peptide vendors · FDA peptide regulation in 2026
See every vendor we track on the all vendors page, and common questions on our FAQ.