The math behind the match.

1. Read what vendors publish

Once a day, starting at 06:10 UTC, we read the public product listings of each vendor we track. We keep the product, its price, the regular price when it is on sale, its stock status and when we saw it.

Our reader identifies itself as PepSpotterBot and respects robots.txt. A vendor that does not want to be read can add User-agent: PepSpotterBot with Disallow: / to its robots.txt, or write to hello@pepspotter.com.

2. Match the material

Each listing is matched to a compound, an amount per vial and a pack size, as the vendor states them. A listing that does not state its amount is not compared on amount.

3. Price per mg

For a single compound, the comparable price is the listing’s price divided by its total amount.

4. Blends: the exact mix, per vial

A blend is compared only with the same blend in the same mix (for example 10 mg + 10 mg) and priced per vial, never per mg. Listings that do not state each ingredient’s amount are shown apart and never ranked, and a mix sold by only one vendor is not called the lowest.

5. Check before publishing

Before a day’s prices appear, an automatic check compares them with the last good day. Too many missing vendors, implausible prices or listings that fail basic checks hold the whole day back, and the site keeps showing the last checked prices.

6. Keep the age honest

Every price shows when it was last checked, and a price not re-checked for 48 hours is marked as stale. Shipping, tax and duties are not included; the vendor’s checkout total is final.

7. Separate currency from geography

Each vendor’s own currency is kept. Canadian-dollar prices are converted at the European Central Bank’s reference rate of the date shown on each comparison. Your destination does not hide vendors; where we have no evidence a vendor ships there, the listing says so.

8. Rank by price alone

Results are sorted by the comparable price. PepSpotter takes no commission and sells no placement, so nothing else moves a listing up.