I know that there is a drink in the USA now that is sold at gas stations/7-11's [who knows wherre else] that is called a "Novacine, Anti-stress, numbing drink"
I actually bought one myself

but haven't drank it yet just because I have not been stressed.
they contain a decent amount of Kava extract, which surprises me.
anyways idk if they have them in the UK but they're only about $3
(not sure euros) a can.
haven't tried strips though, sorry.
havent tried any Kava atually, I'm curious to what it is/does really.
anyways I thought maybe you'd like to know about that drink.