How these numbers are built

1. Where the prices come from

Every vendor indexed here runs a public product feed on their own storefront. We read that feed directly, product by product, including the individual size variants that sit behind a drop-down. Nothing is typed in by hand, nothing is copied from another comparison site, and nothing is estimated. The date the catalogues were read is printed at the top of every page on this site, and it is the date the numbers are true for.

2. What gets excluded, and why

Two groups never enter the index.

• Not a research peptide. Bacteriostatic water, sterile diluent, reconstitution kits, apparel and general supplements. They are in these catalogues but they are not what this index measures.
• Not a vial. Capsules, tablets, nasal sprays, topical serums and foams. This is the exclusion that matters most. A thirty-count bottle of 500mcg oral capsules is arithmetically "15mg" and is not remotely comparable per milligram to a lyophilised injectable vial. Mixing the two produces a cheapest-vendor verdict that reads well and is wrong. We would rather index fewer products than publish a wrong answer.

3. How a price becomes a per-milligram figure

The vial price is divided by the milligrams of peptide in the vial. For a single compound that is straightforward. For a blend it is not, because vendors label blends three different ways — a stated total (“GLOW 70mg”), a component list (“BPC-157 10mg + TB-500 10mg”), or a ratio (“10/10mg”). All three describe the same vial. We normalise every blend to total peptide mass, which is the only figure that makes two vendors' blends comparable.

4. How the cheapest vendor is chosen

Per compound, we take each vendor's cheapest per-milligram listing, then rank the vendors on that figure. Sticker price never decides it. That is why a 30mg tirzepatide vial at $139 outranks a 10mg vial at $79, and why the boards you see elsewhere — which sort on sticker price — regularly crown the wrong vendor.

5. The value score, in full

Cheapest is not the same as best buy. A vial that is four percent cheaper from a vendor you have never successfully ordered from, that makes you create an account first, and that stocks only one size, is not obviously the better order. So every listing also carries a value score out of ten. Here is every point, so you can check it:

1. Effective price — up to 5.0. Cost per milligram after any always-on discount code that applies. ZestyRat carries a standing 10% code (SHAUN10), so their listings are scored at the price you actually pay, not the shelf price. Everything above the cheapest scores 5.0 × (cheapest ÷ this)1.6 — deliberately steeper than linear, so a 25% premium costs real points instead of being waved through. The cheapest listing does not automatically max out either: it starts at 4.6 and earns the last 0.4 by how far clear of the runner-up it actually is, reaching 5.0 only at a 25% lead. A one-cent win and a thirty-percent win should not read as the same result.
2. Reader outcome — up to 2.0. What actually happened when our readers ordered. ZestyRat is the most-ordered vendor across our network and every reader order has shipped, so it takes the full 2.0. Ascension has confirmed reader orders and paid-out referrals on a smaller sample. Vendors with no reader order history yet are scored on published terms alone and cannot earn this outright.
3. Checkout and terms — up to 2.0. Open checkout scores higher than one that forces an account first. A standing discount code and a free-shipping threshold each add. This is the part that decides ties, because it is the part that changes your landed cost.
4. Size choice — up to 1.0. Whether the vendor actually stocks the vial size you want for this compound, or only one option.

Two consequences worth stating plainly. First, the vendor that pays us the most commission does not win every row — it wins where the arithmetic says so, and sits below vendors we earn less from where it does not. Second, the score moves when the prices move: it is recomputed from scratch every time the catalogues are read, and no part of it is typed in by hand.

6. What this index cannot see

A product feed does not contain shipping cost, dispatch speed, a free-shipping threshold, an always-on discount code, or whether checkout demands an account first. Those move the real landed cost, sometimes by more than the price gap. Where two vendors sit within a few percent of each other on this board, treat it as a tie and let those factors decide.

7. Sources and independence

Prices: the three vendor storefronts listed on the vendors page, read August 26, 2026. Vendor background, shipping history and COA practice: Peptides Uncaged vendor reviews. Discount codes: the Peptide Deal Board, where each code is tested at a live checkout.

Links to vendors are affiliate links and we say so on every page. No vendor pays for placement, sees this page before it publishes, or can change a row. If a vendor we earn nothing from were cheapest, they would sit at the top — which is exactly what happens on 21 of the 38 contested compounds on this board.

8. Correction policy

Prices change without notice and vendors reorganise catalogues. The vendor's own checkout is always the authority. If a figure here disagrees with the storefront, the storefront is right and we want to know — the index is rebuilt from the live feeds rather than patched by hand.