Why not cash on delivery
Cash on delivery works where a supplier controls its own courier. It does not fit standard UK carrier practice, so offering it would mean promising something the delivery network does not support.
What is available
Cryptocurrency, paid in USDT, which carries a pre-payment discount because it settles before dispatch and costs nothing to process. And card, Apple Pay or Google Pay through Whop's hosted checkout.
Both are settled before dispatch. Nothing ships against an unpaid order.
Between order and parcel
An order is confirmed at checkout with delivery details, payment is taken, and the parcel is packed for the expected transit window. Each box carries its batch number and printed verification code, so the code can be checked before the packaging is opened.
Damaged, incorrect or undocumented material is far easier to resolve while the box is still sealed and verifiable, so it is worth raising before opening where possible.
Research use only. This article is explanatory and recommends no use, quantity or procedure. REVIVE LAB supplies reference materials for laboratory research. These are not medicines and are not for human or veterinary consumption. Anyone considering the use of any compound in humans should do so only under qualified medical supervision.