How the price rank is made

A store's price score (0 to 100) comes from one figure, its price index: the middle value of its price ratios, where each ratio is a price per mg at the standard size divided by the median for the same peptide in the same format (kits against kits, single vials against single vials). An index of 1.00 is typical and scores 50; half the median or less scores 100; twice the median or more scores 0.

Nothing else adds or removes points: not certificates, guarantees, payment methods, shipping times, catalog size, domain age, warnings or reader votes. Those facts are shown on each store's page, marked "shown, not scored". A high rank means low prices compared with other stores. It is not a finding on quality, purity, safety or whether a store delivers.

Method version 2.1. Data of Oct 4, 2026; this edition built Oct 4, 2026.

1. One price per peptide

For each peptide, the standard size is the vial size most stores sell, in mg. A store's price for the peptide is its cheapest in-stock listing at that size, as price per mg. Listings at other sizes are shown on its page but not compared.

2. The median for each format

Listings fall into two formats: kits (packs of 2 or more vials) and single vials. A kit is cheaper per mg by its format alone, so for each peptide there is a median price per mg for kits and one for single vials, taken over every store on file that sells it at the standard size, ranked or not. A format needs at least 3 stores; a listing in a format that fewer stores sell is not compared and does not count.

3. A ratio for each price

A single vial's ratio is its price per mg divided by the single-vial median. A kit's ratio is its price per mg divided by the kit median, except that a pack is never counted dearer than a single vial at the same price per mg: when at least 3 stores sell the peptide as a single vial, a kit's ratio is the lower of its kit ratio and its single-vial ratio, the second counted as at least 1.00. So a kit that costs no more per mg than the typical single vial never counts as dearer than typical.

single vial: ratio = price per mg ÷ single-vial median
kit: ratio = the lower of (price per mg ÷ kit median) and the larger of 1 and (price per mg ÷ single-vial median)

The rule on real medians: BPC-157 at its standard size has a kit median of $0.82 per mg (38 stores) and a single-vial median of $5.00 per mg (27 stores). Three example prices:

a 10-vial kit at $0.66: $0.66 ÷ $0.82 = 0.80; against single vials 0.13, counted as at least 1.00; the lower is 0.80
a 10-vial kit at $1.65: $1.65 ÷ $0.82 = 2.00; against single vials 0.33, counted as 1.00; the lower is 1.00
a single vial at $4.50: $4.50 ÷ $5.00 = 0.90

4. The price index

A store's price index is the middle value (the median) of its ratios. With an even number of ratios it is the average of the two middle ones. A store needs at least 3 ratios; with fewer it is listed under "Too few prices to rank". The median is used, not the average, so one odd price (a misread listing or a clearance price) cannot move a store far.

5. The price score

The index is a ratio, so it is scored on a doubling scale: half the median is as far below typical as twice the median is above it. An index of 0.5 or less scores 100, 1.00 scores 50, 2 or more scores 0, in a straight line on the doubling scale between. The score is rounded to one decimal.

score = 100 × (log2 2 - log2 index) ÷ (log2 2 - log2 0.5) = 100 × (1 - log2 index) ÷ 2, kept between 0 and 100

The lowest price index in this edition belongs to Peptides Wholesale (Netherlands). It has 48 comparable prices (48 kits). Its ratios from lowest to highest, to two decimals:

0.37, 0.39, 0.41, 0.45, 0.46, 0.47, 0.48, 0.50, 0.52, 0.54, 0.55, 0.55, 0.55, 0.55, 0.56, 0.59, 0.59, 0.60, 0.61, 0.63, 0.66, 0.67, 0.71, 0.73, 0.73, 0.74, 0.82, 0.83, 0.86, 0.86, 0.87, 0.89, 0.89, 0.90, 0.90, 0.93, 0.97, 0.98, 0.98, 0.98, 0.98, 0.98, 0.99, 1.00, 1.00, 1.00, 1.00, 1.00

The middle value, the average of the 24th and 25th of 48, is 0.733, so:

score = 100 × (1 - log2 0.733) ÷ 2 = 100 × (1 - (-0.448)) ÷ 2 = 72.39, rounded to 72.4

Its page lists every price, the median it was divided by and the source of each.

Only stores a buyer can order from are ranked. These are listed apart, each with its reason, and their pages show the record:

• A store whose status on file is closed or parked, or that has a closing notice on file, before or after its date, until it is checked again. Today: 1.
• A store whose own site did not take orders on the site when read (checkout disabled, orders refused on the site, or a banner saying the site is under construction with orders via a chat app), as a dated note by PeptidesGrid (our sister site) records, until it is checked again. Today: 3.
• A domain that PeptidesGrid (our sister site) records as using another store's name without being one of that store's known domains. It is never linked, and the store it names lists it under its other domains. Today: 10.
• A store with fewer than 3 comparable prices: "Too few prices to rank". Today: 31.

Of 111 stores on file, 66 are ranked. A warning that a named outside source has published about a store does not change its price rank: it is quoted with its source and date on the store's row in the ranking and at the top of its page. We make no finding of our own.

Scores are compared to one decimal. Equal scores are ordered by the lower average of all the store's ratios on the doubling scale (a geometric mean, so every price counts, not only the middle one), then by more prices compared, then by the store name A to Z, then by the domain. No two stores share a place.

Each store's page shows these facts from its own pages and the domain registry, each with its source, so a buyer can judge the store beyond price. None of them adds or removes points:

• Where it ships from and to, and its payment methods
• Its certificate (COA) practice, and the test labs it names (the store's own claim; this site does not check or rate them)
• Its stated shipping time, guarantee or returns policy, free-shipping threshold and minimum order
• Its domain's registration date and age, and its catalog size
• Who it sells to, when its home page states who may buy (a kind of buyer, a qualification or a minimum age), quoted with the page and date read
• What it is, when its own pages describe something other than a research-peptide store, and prices that are not per mg (such as monthly program prices)
• Warnings published by a named outside source, dated notes on its own site, related stores and look-alike domains

• Prices and store facts (shipping, payment, certificates, guarantee): read from each store's own pages by PeptidesGrid (our sister site) and checked for pack size. Facts checked between Sep 25, 2026 and Oct 4, 2026.
• Stores read by this site itself, because they are in neither shared data set: RTT Peptides, Peptides Wholesale (Netherlands) and Linux Health. Their prices and facts come from their own public pages (plain page requests at least 2 seconds apart, no logins, forms or carts), each with its source page and the date read (Oct 4, 2026). Prices in other currencies are converted to US dollars with the same FX table the shared prices were converted with (PeptidesGrid (our sister site), Oct 2, 2026) and priced at the standard size by the same rules; the same code scores them, and their prices join the medians like every other store's.
• Who it sells to: each store's home page, read by this site (Oct 4, 2026); a store whose home page could not be read (blocked, on the no-read list of PeptidesGrid (our sister site), or not answering) has no such line.
• Dated notes on each store's own site, and which domains use another store's name: PeptidesGrid (our sister site), read at the import of Oct 4, 2026 (notes checked from Sep 25, 2026).
• Domain registrations, look-alike domains and the stores' own statements about them: registry records and the named sources on each store's page (records of Sep 27, 2026), plus RDAP records this site fetched for domains the shared records lacked.
• Store status and closings: dated, quoted sources (records of Oct 4, 2026).
• The store list and all of the above are shared with Bonded (our sister site), which ranks the same stores by reader votes. Votes play no part here.

It is a price comparison. It is not a test of any product, a rating of quality or purity, a finding that a store is trustworthy, safe or unsafe, or advice to buy. A store can rank high on price and still sell poor products or fail to deliver; read its store facts and record. Stores listed here label their products for research use only; this site gives no medical information and no dosing.

Something wrong in a price or a fact? Each one links its source. Corrections change the data, and the next build ranks every store again the same way.