Harshly worded but a sound caution.
There’s quite a bit of talk about “micro-dosing” - but in the world of illicit drugs you have no way of knowing the true efficacy and proper dose of what you’re taking. I heard Jordan Peterson say in a podcast that a certain percentage of people who take hallucinogenics suffer some sort of permanent psychological impairment - including full on psychosis. But I’ve also read that micro doses of hallucinogens have a great deal of promise for treating depression.
Ketamine shows a lot of promise in treating clinical depression.
As for micro-dosing, I've heard a good things about the Stamet's Stack.
Same author:
A fascinating interview between Tim Ferriss and Paul Stamet's:
https://tim.blog/2018/10/15/the-tim-ferriss-show-transcripts-paul-stamets/
I've yet to try the above but Ginkgo Biloba standardized to 24% flavone glycosides 240mg/daily has been a winner!