[pmoriarty]

Shulgin did suffer a stroke and dementia in his old age. His wife, who probably did just as many (and many of the same) substances he did survived him and is doing fine.

Something else to consider is that Shulgin said he usually only ever did maybe two or three sessions with any given substance, and then moved on to another one. It could be that one or more of them was beneficial, but he might not have taken enough of those particular ones to help. In contrast, Stanislav Grof had over 100 LSD sessions.

I don't think enough is known about the relationship between psychedelics and neurodegenerative diseases to say how and which psychedelics affect them, but there are some interesting ongoing studies to see what effect microdosing LSD has on Alzheimer's disease, the Phase 1 trials of which have recently completed:

https://newatlas.com/science/microdosing-lsd-alzheimers-phas...

[refurb]

Sasha Shulgin tested a lot of compounds, so making any claim would be tough - some might have helped and some might have hurt.

It can take only a minor chemical modification to turn a benign drug into a neurotoxin one.