Price Comparison Methodology

Where prices come from

Every price is copied from a publicly accessible supplier product page. Nothing is estimated, inferred or generated. Where a figure is not published, the table shows “Not available” instead of a guess.

Each row links to the original supplier listing so you can check the source yourself. Source links are never hidden or rewritten to conceal the destination.

How often prices are checked

Prices are entered and re-checked manually. Each record stores the exact timestamp it was checked, and every row shows that date.

Rows are labelled Verified recently, Recently checked, Older data or Unable to verify. The number of days behind each label is a configurable setting held in the database, not a hard-coded value, so the thresholds can be tightened as checking frequency improves.

This database is not live. Prices can change at any moment on the supplier's own site, and the listed price there always takes precedence over anything shown here.

How currencies are handled

The supplier's original listed price and currency are always stored and always shown. Nothing overwrites them.

Because suppliers list in different currencies, every price is also converted to US dollars so that listings can be ranked against each other fairly. The conversion uses a published market rate fetched from an independent exchange-rate provider, and the rate, its timestamp and its source are saved alongside each price check. Historical records keep the rate that applied when they were collected, so past figures never change when rates move.

Converted figures are labelled as estimates and marked with an approximate sign. Sorting, ranking and summary statistics such as lowest, highest and median all use the USD values; the original currency is shown next to them so you can always see the real price you would pay. Where a rate is unavailable, the listing keeps its original price and is excluded from cross-currency ranking rather than being converted with a guessed rate.

How price per mg is calculated

Price per mg is the listed price divided by the total mass in the product, where the mass is clearly stated by the supplier in mg, mcg or g. It is calculated in the original currency and again in USD, using the same rate stored with that price check.

Where the quantity is given in IU or ml, or where the mass is unclear, no price per mg is shown. Shipping is not included in price per mg because it varies by destination.

How different vial sizes are handled

Each vial size is a separate product. A 5 mg vial and a 10 mg vial of the same compound are never merged, averaged or presented as alternatives to one another in a single row.

Multi-vial kits record the number of vials, and total mass is used for any per-mg calculation.

How sale and promotional prices are handled

Every price record is tagged as a standard price, a sale price or a promotional price, and that tag is shown in the table. Temporary discounts are not presented as if they were regular pricing.

How unavailable products are handled

If a product goes out of stock it is marked out of stock rather than removed. If a product disappears from a supplier's site entirely it is marked unavailable and its historical price records are kept.

Nothing is deleted to make a supplier look better or worse; historical records remain visible on the price history charts.

How supplier locations are verified

Country, city or region are recorded only where the supplier publishes them. A full address is recorded only where it is publicly published by the supplier itself.

Where a location cannot be confirmed from public information it reads “Not available”. A stated shipping origin is not treated as proof of company location.

How COA and testing information is recorded

Testing information is recorded as published: whether a certificate of analysis is available, on request, not published, or not verified, together with a link and test date where those are public.

The presence of a COA is a record of what a supplier publishes. It is not an independent verification of purity, identity or safety, and this site performs no laboratory testing of its own.

How affiliate relationships are disclosed

Each supplier record carries flags for affiliate relationship, sponsored placement and paid placement. Where any of these apply, a badge is shown directly in the comparison table next to that supplier.

Sorting and ranking are driven only by the data you select — price, price per mg, supplier, location or recency. Commercial relationships never influence position in the table, and no supplier can pay to appear higher.

Price is not a measure of quality

The lowest listed price is described as the lowest listed price, never as the best supplier. Price, testing information and stock status are shown as separate columns so you can weigh them yourself.

All products listed are research-use products. This resource is educational and contains no medical advice, dosing guidance for human use, or purchasing recommendation.