The study mentions the concern might be with gut bacteria creating TMAO, which can cause atherosclerosis issues, but ConsumerLab says the creation of TMAO only lasts a few hours, which has seemed to limit any choline-TMAO issues in other studies.
I would submit that this study reviewed patients of doctors who prescribed Alpha-GPC, in South Korea. Consequently, the prescriptive use may have been throughout the day, rather than all at one time, which would very much raise TMAO levels, overall.
The Cleveland Clinic has published studies showing that compounds i balsamic vinegar and extra virgin olive oil actually block the gut bacteria that makes the detrimental conversion, if taken at the same time. Whether or not that addresses this newly found stroke issue is just not known.
We will stop out Alpha-GPC use when we finish up our bottle.
Could you try egg yolk lecithin? It is high in choline.