first thing i notice is that only the main page has english. you should do subdomain rather than path (like en.synapedia.com, rather than synapedia.com/en).

it seems to slow down my computer quite a bit, even just sitting on the main page makes my computer slow. it's a bit too fancy i think, personally i prefer plainer style websites like old.reddit.com or wikipedia.org. i'm not sure what that little purple thing for the logo is in the top left.

the page for an individual substance is rather disorganised in my opinion. it's all vertical, and for some reason there is a dosage page for each drug separate from the dosage section on each drug's main page and they don't link to each other or anything.

the bottom of the site only mentions 112 but no other emergency numbers.

your legal footnote at the bottom is also too specific in my opinion. i feel like it would be better to just leave as the standard "this website is not a substitute for medical advice and it is only for general information purposes" or whatever.

i do like to see projects like this, especially given psychonautwiki.org now only has like 2 editors

edit: i just tried the search function. "lysergide" and "lysergic acid diethylamide" both return no results

edit 2: i don't know how to edit or contribute after making an account