https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4522929/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086302/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5056806/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4522929/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086302/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5056806/
It has good caffeine content, but apparently has a slower absorption. Helps you to keep focused, without the strong highs and lows you have with pure coffee.
Switched to Mate or PG Tips tea as my morning drink, typically with loose leaf mate in a French press.
South American (Cruz de Malta , Taragui) are readily available on Amazon prime and much cheaper than the American brand Guayaki
As with a lot of other things observe yourself and don't blindly trust studies. even if the study finds positive results for 90% of people you may be in the 10%.
I drink dandelion coffee now. It's quite good.