What customs needs
A shipment is assessed on its declared contents, its classification and its documentation. Accurate description matters: a misdescribed parcel is more likely to be held, and misdescription is itself a problem regardless of what is inside.
Where responsibility sits
The importer is responsible for ensuring the material may lawfully be imported and held where they are, and for holding any authorisation required. That responsibility does not transfer to the supplier by virtue of having bought from them.
Variation between jurisdictions
Rules differ substantially. Some require an institutional recipient, some require prior authorisation, and some restrict particular compounds outright. A compound freely available in one country may be controlled in the next.
Before ordering
The useful check is whether the specific compound may be imported and held at the destination, made before the order rather than after the parcel is held. This page is general description, not legal advice.
Research use only. This page is explanatory and does not recommend any 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.