That's what I was wondering, whether tolerance clouds the issue. I'm not worried but if it were inexpensive and private I would get the test just to see. Unfortunately 23andme isn't that easy to do anonymously.

Oh well... maybe I'll have another cup?

An example of how the findings get summarized in the popular press. Despite the title, they did interview the lead researcher:

After canceling booze, Canada is now coming for your coffee
By Alex Mitchell
February 16, 2023 | 12:13pm

... "Often, when I give a talk, someone will say, 'oh, I'm definitely a slow metabolizer because if I drink a cup of coffee in the afternoon it keeps me up at night,' " El-Sohemy said. "But there's currently no link in terms of those types of physiological responses to caffeine and speed of metabolism."

- https://nypost.com/2023/02/16/after-can ... offee/amp/

Yeah, I was going to say that I think the issue of whether a certain amount of coffee makes you jittery is not the same as whether you clear the caffeine in three hours or six. That's just my hunch though.

baldheadracing wrote:An example of how the findings get summarized in the popular press. Despite the title, they did interview the lead researcher:

Back in the day, the only people who read research studies were other researchers who used them to make incremental advances in their field. They understood that seminal works were rare, and that most studies simply pointed in the direction where more research was needed. Sadly, the media (and public) have 'discovered' research studies, where they often pull a few sentences out of context and publish them as absolutes. No wonder many don't trust science anymore given the fatigue from the ping-pong'ing in the press and social media every time a new study comes out.

EDIT: This is just a crabby old-guy rant and nothing toward you Craig.

espressoren wrote:Yeah, I was going to say that I think the issue of whether a certain amount of coffee makes you jittery is not the same as whether you clear the caffeine in three hours or six. That's just my hunch though.

For whatever it's worth, the amount of caffeine that will ruin my sleep is small (after 3pm) whereas the amount of caffeine needed to make me feel jittery is quite large.

Brewzologist wrote:EDIT: This is just a crabby old-guy rant and nothing toward you Craig.

No worries, that didn't even occur to me .

If you know if you are a fast metabolizer of caffeine or not, then this is a decent summary of current research, 7:11 long; skip to 3:49 to get to:

tl;dw: some of the health benefits of coffee are only for fast metabolizers. Slow metabolizers have adverse affects.

Again, having the genes of a fast metabolizer of caffeine does not necessarily imply how caffeine affects you in terms of keeping awake, jitters, etc.

Great collection of studies in that video. Very interesting and also entertaining.

I guess I'll keep drinking coffee.

baldheadracing wrote:Again, having the genes of a fast metabolizer of caffeine does not necessarily imply how caffeine affects you in terms of keeping awake, jitters, etc.

But caffeine causes awake and jitters. If the body gets rid of caffeine (faster than some), those two effects are gotten rid of too, no?