I was scared to order from overseas but these vendors are legit — looking for input

Answering the narrow version, because the broad one does not have a single answer. Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion. Synthesis, testing, and cold-chain shipping have floors. A price well under the floor means something was skipped, and the two things that get skipped are testing and content.

Ask again with the specifics and you will get a better answer than this one.

Dr.NateNeph said:

Prices dramatically below market are the strongest single signal, and the reason is arithmetic rather than suspicion.

Agreed, with a caveat about community reputation: it is a lagging indicator. Reports arrive weeks after orders, so a supplier can look excellent for a month after quality has already changed.

wanda_boise said:

One order arrived in nine days, one was held at the border for a fortnight, and one came back with a seizure notice.

Right, and one flattering data point from a group buy is not consistency. Consistency means separate batches, separately commissioned, over months.

Happy to go further on any of that.

Clinical perspective, offered as context rather than as advice.

International shipping tracking for cross-border ordering orders: my experience with customs in the US when ordering from overseas:

Package cleared customs in 2 days, no issues.

Tips: always include a copy of your prescription, declare medication properly on customs forms, keep quantities reasonable (personal use = 3 month supply max), and use a vendor who has experience shipping to your country.