How we track prices.

What we track

For every vendor in the directory, we track each research peptide they publicly list, the variant (vial size, typically in milligrams), the listed price in US dollars, and the URL of the product page. We do not track shipping, taxes, discount codes, bundle deals, or promotional banners. The number you see is the sticker price the vendor displays on the product page at the time of scrape.

How prices are collected

An automated scraper visits each vendor’s site on a recurring schedule. For each product, it first tries to read structured data the vendor has already published — JSON-LD Product markup, microdata, or Open Graph tags. About 70–80% of vendor pages expose enough structured data that no language model is needed. For the remaining pages, a small open-source code-extraction model reads the HTML and pulls the price and variant.

Every extracted row is then validated before it lands on the public index. The price must appear verbatim in the source HTML, fall inside a sanity range, and be within a reasonable delta from prior scrapes for the same vendor and peptide. Outliers are flagged for human review, not auto-published.

How prices are normalized: $/mg

Vendors sell the same peptide in different vial sizes — 5 mg, 10 mg, 30 mg — so a raw price can’t be compared across listings. We convert each listing to dollars per milligram by parsing the variant string for a mass value and dividing the listed price by it. That’s the number sorted on the peptide pages and the homepage.

Variants that don’t parse to a milligram amount — bacteriostatic water (sold in ml), nasal sprays, multi-compound bundles, price ranges across multiple sizes — show — instead of a price. They’re still listed; they just can’t be ranked by $/mg and we don’t pretend otherwise.

How vendors are ordered

On peptide pages, vendors are sorted by $/mg ascending: the cheapest listing on top. There is no tiebreaker for vendor reputation, brand, or affiliate payout, because we don’t track any of those. Where a vendor has multiple variants of the same peptide, the row reflects the variant they currently sell — you may find a better $/mg in a larger size on the vendor’s own page.

The homepage ranks peptides by the lowest tracked $/mg across all vendors carrying them. Vendor count and best variant are shown alongside so the comparison is in context.

How often the index is refreshed

The scraper runs daily. Each peptide page displays a “Prices refreshed” date based on the most recent successful scrape for any vendor listing that peptide. Vendor pages show the same stamp for their own listings. If a date looks stale, a vendor’s page may have changed shape and we may be actively refixing the extractor — always verify the current price on the vendor’s site before purchase.

What we do not do

• We do not test, score, grade, or rank vendors. There is no editorial review.
• We do not accept payment for inclusion or for higher placement on the index.
• We do not publish dosing, efficacy, or health claims about the peptides listed.
• We do not act as a reseller. Outbound vendor links go directly to the vendor’s product page. Where an outbound link earns an affiliate commission, that does not change which vendors appear or how they are ranked.
• We do not maintain user accounts, mailing lists, or first-party tracking cookies.

Corrections

If a price on the index is wrong, a vendor has gone offline, or a peptide is misattributed, the index is wrong and we want to fix it. Email [email protected] to flag it. Until corrected, the index errs on the side of leaving stale rows visible with a refresh date rather than showing nothing at all.