Find a source, get a test kit, test meticulously, stick to the source. If you're getting a new source, test again and try a very small dose first. Also, beside

Find a source, get a test kit, test meticulously, stick to the source. If you're getting a new source, test again and try a very small dose first. Also, besides Erowid, other reliable information sources have popped up. Psychonautwiki, tripsit.me for example. Some countries have anonymous test pipelines via hospitals or universities, but it's less common. Test kits are available online.