How we check vendors, prices and products
We publish three kinds of data about research peptide vendors. Each one is collected the same way for every vendor, and none of it can be bought.
- Transparency checks: six tests of what a vendor makes public about itself.
- Prices: what each product costs per milligram, from the vendor's own product feed.
- Lab tests: what's actually in vials bought anonymously (not started: testing isn't funded yet).
We also keep a log of closures, raids, warning letters and domain changes.
1. The transparency score (100 points)
The score measures openness, not product quality. Each point comes from information anyone can verify, and each vendor profile links the evidence we used.
| Check | How we check it | Points |
|---|---|---|
| Domain age | Registration date from the domain registry (RDAP). Older domains have a longer public track record. | 3+ years: 20 · 2–3 years: 15 · 1–2 years: 10 · 6–12 months: 5 · under 6 months: 0 |
| Public certificates of analysis (COAs) | Whether the vendor posts COAs anyone can read, and whether they're tied to specific batches. | Batch-specific and public: 25 · generic or sample only: 12 · on request: 5 · none: 0 |
| Independent lab named | Whether those COAs come from a named third-party lab rather than the vendor itself. A lab mentioned elsewhere on the site doesn't count unless we can see a COA that names it. | 10 |
| Business identity | Whether the site states a company name and a physical address. | Both: 15 · one: 8 · neither: 0 |
| Policies | Whether shipping, refund and terms pages exist. | All three: 15 · two: 10 · one: 5 |
| Buyer-protected payment | Whether the vendor states that it accepts cards or PayPal, which let buyers dispute a charge. Crypto, Zelle and similar methods don't. | 15 |
Unverified means zero. If we can't confirm an item, it scores 0 and the profile says so. When a site blocks automated checks, we read its most recent Internet Archive copies (no more than 180 days old) instead, and every finding from an archive copy is linked and dated. We never try to get past a site's bot protection. Vendors can send evidence to [email protected].
Red flags are listed separately and never folded into the number. Examples are a closure announcement, an FDA warning letter or a look-alike domain. Each one is linked to its source.
Who gets ranked: our best peptide vendors list only includes live vendors with all six checks completed. Two kinds of vendor are never ranked, picked, shortlisted, suggested as an alternative or called out as cheapest, whatever their score:
- vendors with documented red flags, such as a look-alike of a closed seller; and
- vendors named in an FDA warning letter, a lawsuit, a seizure or another regulator's action in the past three years. Being named isn't proof that a particular product is bad, but we don't recommend a vendor while such an action is recent.
Their profiles and full price tables stay published, with the reason shown.
Domain age: the score uses the date the domain was last registered. When the Internet Archive has copies of the domain from before that date, the profile says so: the name was in use before, possibly by a different owner, which is a reason for extra care rather than reassurance.
Context we show but don't score: the domain's registrar and expiry date (from the same registry record), the date of the first Internet Archive copy, and a traffic rank from the Tranco list, a research ranking of the most visited million sites that combines several popularity rankings over 30 days. We use the list Tranco publishes for download. A vendor outside the top million shows no rank, which only tells you its traffic is small.
2. Prices
- We read each vendor's public product feed: the same machine-readable catalog its own website uses (for example Shopify's products feed or WooCommerce's store API). We don't log in, add to cart, or use discount codes.
- Each listing is matched to a peptide by name, and the vial size is read from the product or variant title. Listings we can't read reliably are left out rather than guessed.
- Price per mg = listed price ÷ (mg per vial × number of vials). It uses the labeled amount; a lab test is the only way to know the real amount.
- Prices are refreshed daily, exclude shipping, taxes and coupon codes, and are shown in the vendor's currency. Listings in other currencies (currently Australian dollars, Canadian dollars, euros and British pounds) are converted to US dollars at the European Central Bank's reference rate for $/mg comparisons, and marked as converted.
- Where a vendor publishes no product feed, we read prices from its public product pages (structured product data), within the same request limits. Multi-vial kits are compared separately from single vials where possible, because kits are bulk deals. Wholesale lots of more than 20 vials (for example "100 vials at 50% off") are left out of comparisons altogether.
- Compounds that are sold under similar names but differ chemically are priced separately: CJC-1295 with and without DAC (Mod GRF 1-29), Semax and Selank and their N-acetyl amidate forms, MGF and PEG-MGF, GHK-Cu and AHK-Cu. Fragments such as "TB-500 Frag 17-23" aren't counted as the parent peptide, and a blend that contains a compound we don't track isn't counted as a simpler blend.
- Vendors with documented red flags stay in the price tables for completeness, but we don't link out to them. Neither they nor vendors with a recent enforcement action (see above) are listed as a cheapest option or in a shortlist.
Vendor price index
To compare vendors rather than single products, we take each vendor's lowest $/mg for every peptide that at least three vendors sell, divide it by that peptide's median listing, and use the median of those ratios. 1.00 means a vendor's prices sit at the market median; 0.80 means they're typically 20% cheaper. A vendor needs at least three comparable peptides. See the price ranking.
Head-to-head comparisons
Our vendor comparisons put two vendors side by side using the same checks and prices as everywhere else; nothing is scored differently. We build a pair only when people search for the two together, both vendors are active, and we have enough on both: prices for at least three of the same peptides, or at least four of the six checks completed for each. A comparison mostly repeats what the two vendor profiles already say, so we ask search engines to index one only once our search data shows people looking for that pair; until then it's here for readers. In the price table, each vendor's offer is picked as on our price pages (single vials before kits, in stock before out of stock), and a gap under 0.5% counts as a tie. A comparison never names a winner on quality, because we haven't lab-tested these vendors yet. A vendor we don't recommend (red flags or a recent enforcement action) carries the same warning there as everywhere else.
3. Status and alerts
We check every vendor's website regularly and record whether it's live, down, redirecting to another domain, or closed. Closures, raids, warning letters and lawsuits are only logged with a public source, such as a regulator's website, a court record, a news report or the vendor's own announcement.
4. Lab tests (not started yet)
We haven't tested any products yet. When testing starts, this is the method: We buy anonymously at full price, photograph and log every package, keep a sealed retain sample, and send vials to independent labs. At minimum we test purity (HPLC), identity (mass spectrometry) and quantity against the label. Every result is published, including failures. Details are on our tests page.
What we never do
- Accept payment, free products or "partnership" deals in exchange for a score, a ranking or coverage.
- Let affiliate commissions affect any score, rank or sort order. See how we make money.
- Publish dosing, injection or "protocol" advice. We describe evidence and law, not how to use these compounds.
- Change a date on a page unless the content or data actually changed.
Limitations
Public information can be faked, and a transparent vendor can still ship a bad batch. One lab test describes one vial. Shipping claims come from vendors' own pages. Use our data as one input, not a guarantee, and see our editorial policy for how we handle mistakes.