Two storefronts, the same named product, a 40% price gap. The gap is not a mystery, and understanding what creates it is the difference between a good deal and a bad one. Here are the four factors, in order of how often they matter.
Factor 1: Verification cost
Per-batch third-party testing — identity, potency, contaminant panels — is a real, recurring cost: lab fees, sampling labor, and the batches that fail and get discarded rather than shipped. A seller who runs the full per-batch process carries that cost in every pack; a seller who does not carries zero of it, and the difference is visible in the price. This is the factor behind most “suspiciously cheap” listings in the category, and the official vs reseller post is the buyer-side version of the same analysis. The COA is the document that separates the two: a verifiable lot number and a report, or a price with no denominator.
Factor 2: Pack economics
The per-mg curve from the cost per mg guide: small packs cost more per milligram, large packs less, and the gap between them is normal, not a ripoff. A buyer comparing a 180mg starter pack at seller A against a 1000mg pack at seller B is comparing two different points on the curve and reading a “price difference” that is really pack size. The formula corrects for it; the eye does not.
Factor 3: Format and positioning
Bar vs tablet tooling, flavor development, packaging, and the margin structure of the channel (direct from source, single reseller, marketplace fee stack) all move the final number without moving the product. Marketplace listings in particular stack fees that a direct store does not carry — which is why the same product can be priced higher on a marketplace and still be the source’s product. The price guide covers the market structure.
Factor 4: The inventory clock
Age of stock. A batch that sat eight months in a reseller’s warehouse is the same lot number at a worse storage state — the storage guide explains what heat, light and humidity do to a pack over that period — and clearance pricing on old stock is the most legitimate “good deal” in the category. It is also the hardest one to verify from the outside: the lot number is the check, and the verification routine is the tool. A fresh batch from the source and an eight-month batch from a clearance shelf can carry the same label and different realities, and the lot date is the line that tells them apart.
The decision rule
Run the cost per mg formula on any offer. If the number lands in the market band, it is a normal price — compare the packs, not the tags. If it lands dramatically below the band, the gap is one of the four factors, and the one to assume until proven otherwise is factor 1: the missing verification. The three checks (lot, packaging, seller) test the assumption, and the shop is the reference point for what the source charges. That is the whole analysis — and the FAQ answers the specific comparisons people send us.