Maybe I didn’t get this from the tutorials, but I managed to get rid of a side effect in one of my games, but didn’t understand the reason why.
After upgrading from a tier 1 to tier 2 curing effect I had a ‘concentration + 3’ machine that showed how the side effect was removed (not just inactive, it removed it and opened the slot).
Does this happen if you remove the concentration a certain treshold from the active zone for a side effect?
I retried the setup with a ‘concentration + 1’ machine and then the side effect stayed on (but still in its inactive zone).
Some thing you’ll notice is that side effects can be removed similarly to how positive effects are upgraded.
Some side effects have “cannot be removed” but some can be removed by setting the concentration to a certain range, then putting the ingredient through a specific machine. You have to hover over the side effect to see how it is removed or if it has “cannot be removed”.
Additionally you can replace a side effect with “Cannot be removed” with one that can through shaking and mixing - But that is usually only relevant for Tier 2+ drugs.