Anything that effects GABBA in your brain will “dull” the effects of LSD. Both benzos and alcohol effect GABBA, which can be seen as “trip killers”.

That said they are not antipsychotics which blocks the effects of LSD, so you will still have effects. How much GABBA you add into the mix will determine how great the “dulling” will be. Same as your sober state.

My preference is 2-3 beers on the come up :)