What happens if a lot fails testing?

Testing sits before release, which is the only position where it can affect anything. A result outside specification means the lot does not ship.

This is also why the certificate library only ever grows with lots that met their specification, and why the absence of a certificate for a compound means no lot has been released yet — not that a result is being withheld.

We will not attach one lot's certificate to a different lot to fill the gap. If nothing has been issued, the product page says so.

What this means when a compound is unavailable

A compound listed with no available lot is the visible consequence of testing being a gate. The alternative — releasing material that did not meet specification, or shipping against a previous lot's certificate — would keep the catalogue fuller and make the published evidence meaningless. Given the choice, the gap is the honest outcome, so occasionally a compound has no purchasable lot for a period.

It also means the timing of availability is genuinely outside our control in a way a stock forecast is not. A lot is released when it has been tested and passed, and neither of those steps can be usefully hurried.

The corollary is worth stating in the other direction: because failures are not released, the certificate library is not a representative sample of everything ever synthesised. It is the record of what passed. That is precisely what it should be, but it means the library cannot be read as a quality trend over time.