Wasn’t it the Beach Boys who turned Charlie on to LSD?
https://duckduckgo.com/?q=manson+beach+boys+lsd
Better psychosis through chemistry.
I doubt that Manson “discovered” LSD through his connection to the Beach Boys.
SF was awash with LSD (which was ‘legal’ then and pharmaceutical industry produced) when Manson was living there before heading down to LA.
And Timothy Leary was among those experimenting on prisoners with LSD in the early 60s.