We check what each research peptide vendor actually publishes: lot-level lab reports, shipping and refund terms, company details and customer ratings. Every fact links to its source and carries the date we checked it.
Partner links: we may earn from PSPeptides. How this site is funded
Picks are based on the facts in each review. How we review.
4.6 out of 5 from 268 Trustpilot reviews, the highest rating we recorded, with same-day US shipping on orders before 2 PM EST and batch COAs you can look up on the lab's site.
PSPeptides4.6(268)Our PickPartnerOpenLot COAsUSAPSPeptides is a US research peptide vendor that says it manufactures in a cGMP-compliant facility in Temecula, California.
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American Peptides4.1(69)Most transparentOpenLot COAsUSA (LA)American Peptides (americanpeptides.us) lists a Shreveport, Louisiana address and 76 research compounds, and posts COAs by lot for its products.
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Ascension PeptidesNo Trustpilot ratingBest priceOpenUSAAscension Peptides is a US research peptide store with 42 products and a searchable COA library of 122 records.
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Biotech PeptidesNo Trustpilot ratingOpenBiotech Peptides is a research peptide vendor with a Las Vegas, Nevada business address and phone number on its contact page.
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Core PeptidesNo Trustpilot ratingBest for lab testingOpenLot COAsUSACore Peptides is a US research peptide vendor with an Orlando, Florida address and 104 products listed.
Read the review →Limitless Life Nootropics3.3(164)OpenLimitless Life Nootropics says it carries more than 90 research peptides and posts HPLC certificates on each product page.
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Palmetto PeptidesNo Trustpilot ratingOpenLot COAsUSAPalmetto Peptides is a smaller US vendor with around 25 products and a lot-level COA page.
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Peptide PartnersNo Trustpilot ratingOpenPeptide Partners (peptide.partners) requires a free account and a declared research position or institution before it shows its catalogue, prices or certificates.
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Pure Health Peptides4.5(68)Biggest catalogueOpen · new domainUSA (CA)Pure Health Peptides ships from California by USPS Priority Mail and offers free shipping on orders of $175 or more.
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Swiss ChemsNo Trustpilot ratingOpenLot COAsSwiss Chems sells research peptides alongside other research compounds and lists lab reports by batch ID on its product pages.
Read the review →Peptide SciencesNo Trustpilot ratingReported closedPeptide Sciences was one of the best-known research peptide vendors in the US.
Read the review →| Vendor | Status | Ships from | Lab reports | Refunds | Trustpilot |
|---|---|---|---|---|---|
| PSPeptides Partner | Open | USA | Per lot; lab: N.A. Diagnostics | No returns; defects in 3 days; refund + test cost if purity < 80% | 4.6(268) |
| American Peptides | Open | USA (LA) | Per lot; lab: Bioviridian | Final once shipped; damage within 72 h | 4.1(69) |
| Ascension Peptides | Open | USA | Lot numbers not confirmed; lab not named | All sales final | — |
| Biotech Peptides | Open | — | Lot numbers not confirmed; lab not named | "30-day refund" but no returns | — |
| Core Peptides | Open | USA | Per lot; lab: Vanguard Laboratory | Refund request within 30 days of order | — |
| Limitless Life Nootropics | Open | — | Per product (no lot numbers seen); lab not named | Unopened items within 10 days | 3.3(164) |
| Palmetto Peptides | Open | USA | Per lot; lab not named | All sales final | — |
| Peptide Partners | Open | — | Lot numbers not confirmed; lab not named | Refund only before shipping | — |
| Pure Health Peptides | Open (domain redirects) | USA (CA) | Lot numbers not confirmed; lab not named | No general refund policy; insured parcels only | 4.5(68) |
| Swiss Chems | Open | — | Per lot; lab not named | Peptides non-returnable | — |
| Peptide Sciences | Could not confirm | — | Lot numbers not confirmed; lab not named | Reported closed | — |
"Partner" marks PSPeptides, this site's commercial partner. The same checks apply to every vendor.
No invented scores: every fact links to its source. Full method
Product, shipping, refund, FAQ and contact pages, each saved with a link and the date we checked it.
Is there a certificate of analysis for each lot, which lab ran it, and can it be looked up on the lab's own site?
Every review shows a dated screenshot of the policy page its facts came from, so you can see the evidence.
Every vendor gets the same checklist, our partner included, and every review lists what to watch out for.
Before ordering from anyone, run our eight checks for a legitimate peptide vendor.
We read the vendor's own product, shipping, refund, contact and lab-testing pages, record each fact with its source and the date we checked it, and add the vendor's Trustpilot rating where one exists. We do not buy, test or review effects of any product.
A certificate of analysis for your exact lot that names the lab, a refund or reship policy in writing, a company you can identify by name and address, and clear shipping terms. Price only matters once those are in place.
PSPeptides has the highest customer rating we recorded (4.6 from 268 Trustpilot reviews), same-day US shipping and batch COAs that can be looked up on the lab's site. It is also this site's commercial partner, which is why it carries a Partner tag. Its watch-outs are listed in full in its review.
Third-party sources report that Peptide Sciences shut down in March 2026. We could not confirm this with the company. See our Peptide Sciences review and the alternatives page.