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How We Rate Retatrutide Vendors

Last updated: October 19, 2026

Buying a research peptide online means trusting a seller you cannot inspect in person. Our methodology turns that trust question into checks anyone can repeat: we look for evidence on the vendor's own website and in independent public sources, score each vendor on seven criteria, and combine them into a weighted score out of 10.

Our seven criteria

  • Purity & third-party testing25%Published COAs from an independent lab, batch traceability, stated purity.
  • Pricing & value15%Price per milligram, size options, bundle discounts, no hidden fees.
  • US shipping & fulfillment15%Ships from inside the US, delivery speed, tracking, packaging.
  • Customer support & policies15%Reachable support, clear refund / reship policy for lost or damaged orders.
  • Reputation & track record15%Independent reviews, community feedback, time in business, legal history.
  • Transparency & checkout security10%Real contact details, clear policies, secure checkout, mainstream payment options.
  • Product range & extras5%Breadth of catalog and useful lab supplies.

Purity & third-party testing — 25%

  • Is a certificate of analysis (COA) published for retatrutide, and is it easy to find?
  • Was the test done by a named independent laboratory rather than in-house?
  • Does the COA show identity (mass spectrometry) and purity (HPLC), with a batch/lot number and date?
  • Can a buyer match the COA to the batch they receive?

Pricing & value — 15%

  • What does retatrutide cost per milligram at the most common vial size?
  • Are several vial sizes or multi-vial bundles available?
  • Are shipping, handling or payment surcharges disclosed before checkout?

US shipping & fulfillment — 15%

  • Does the vendor ship from a US warehouse (no customs delays or seizures)?
  • What are the stated processing and delivery times, and is tracking provided?
  • Is there a free-shipping threshold? How are lyophilized peptides packaged?

Customer support & policies — 15%

  • How many support channels exist (email, phone, live chat) and are they staffed?
  • Is there a written refund, return or reship policy for lost, damaged or incorrect orders?

Reputation & track record — 15%

  • What do independent review platforms and research communities say?
  • How long has the vendor been operating?
  • Has the vendor been the subject of FDA warning letters or lawsuits?

Transparency & checkout security — 10%

  • Does the site list a business address, email and phone number?
  • Are terms, privacy and shipping policies published?
  • Is checkout HTTPS-secured, and are card payments accepted (not crypto-only)?

Product range & extras — 5%

  • How broad is the peptide catalog?
  • Are lab supplies such as bacteriostatic water available?

How the score is calculated

Each criterion is scored from 0 to 10. The overall RetaRate score is the weighted average:Σ(criterion score × weight) ÷ 100, rounded to one decimal place. Testing carries the largest weight (25%) because, for an unregulated research compound, independent verification of identity and purity is the single most important protection a buyer has.

Our research process

  1. Discovery. We identify vendors that sell retatrutide to US customers through search engines, research communities and industry coverage.
  2. Site audit. We read each vendor's product pages, COA library, shipping, refund, terms and contact pages and record what is stated — with the date we checked.
  3. Independent signals. We look for reviews on independent platforms, community discussion, domain history and any regulatory or legal actions.
  4. Scoring. Each criterion is scored against the recorded evidence, using the same checklist for every vendor.
  5. Re-checks. Prices and policies change often. We re-verify the ranking at least monthly and update the "last checked" date.

What we do not do

  • We do not run our own laboratory tests. When we discuss purity, we report what the vendor's published COA says and who produced it.
  • We do not provide dosing or medical guidance. Retatrutide is an investigational drug that is not FDA-approved — see our medical disclaimer.
  • We do not publish fabricated reviews or testimonials.

Red flags that lower a score

  • No COA, a COA with no batch number or date, or a COA from an unnamed lab.
  • Crypto-only or gift-card payments with no buyer protection.
  • No physical address, no phone number, or support that only works through social media.
  • Shipping from overseas without clear customs and reship terms.
  • Marketing that makes medical claims or gives dosing advice for human use.

Commercial relationships

RetaRate earns commissions from some vendors, including our #1-ranked vendor. Compensation can influence which vendors are featured and their placement. Read our affiliate disclosure and editorial policy for details.

See the current ranking →