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If you're going to drink decaf, be sure to drink decaf prepared via the Swiss water method. It has the least additives, healthiest option and tastes pretty good.
May you share some brands that follow such method ?
It’s actually hard to find brands that don’t use the water method if you buy “freshly” roasted beans. Unless you go super budget, medium budget beans like Peets, SF bay, etc use water process method.
I'll take this opportunity to plug an instant decaf that recent surprised me (very pleasantly). Our hotel offered this for free in the lobby on a recent trip and I ended up buying some for travel purposes.

https://treelinecoffee.com/collections/on-the-go/products/in...

It's a swiss water method decaf instant that rivals some of the best cafe regular coffees I've had.

At stores/roasters, most will tell you the decaffeination method somewhere on the bag. If they don't it's probably not a brand that cares much about their decaf, so skip it. Make sure you go for as close to roast as possible - decaf goes off a lot quicker than regular coffee.

James Hoffmann did a video on decaff coffee recently[1]. In it he basically says the "scary chemicals" aspect of other caffeine removal processes is basically overblown, and the reason why decaf coffee sucks has less to do with the solvents used and more to do with how the decaffination process makes the beans more prone to staling. In short, there's nothing really special about the swiss water process in particular and there are more important factors to worry about.

[1] https://www.summarize.tech/www.youtube.com/watch?v=yYTSdlOdk...

The point I really liked about that video is that decaf drinkers are probably the most passionate coffee lovers. We're drinking it for ONLY the taste/experience. It's a shame coffee roasters and coffee shops tend to not take it seriously. I know when I'm traveling I often want to stop in a coffee shop and get a nice decaf and relax for a bit, but most shops make it pretty clear it's not going to be a good experience by not putting any effort into featuring/caring about the decaf options.
And chances are the roasters actually care about making it taste good. It's rare but you can find great decaf coffee if you look for it.

To me, it is weird that all coffee revolves around caffeine; I find the complex tastes way more rewarding than the milligrams of caffeine I get from it.

The Ethyl Acetate (aka sugarcane) method is also good, as long as the resulting beans are complemented by the slight fruity flavor added by the process. There's a new plant in Colombia which makes some excellent coffees (provided they are roasted well).

It can be difficult to find roasters who actually care about their decaf coffee beans - they are more difficult to roast and some roasters still turn up their nose at it. Decaf beans stale faster (both before and after roasting) so it's even more important to get fresh beans from a good roaster.

Any roaster recommendations for decaffeinated beans?
Citation needed. It’s possible it may taste the best, but I am skeptical of your claim that it is the healthiest.

One of the common methods of decaffeinating coffee uses supercritical CO2, which is in my view significantly less scary than the “proprietary green coffee extract” used by the Swiss Water process.

I suspect neither is actually harmful. And neither is the chemical solvent based decaf, honestly. Not in levels that are meaningful to health.

Swiss Water's Green Coffee Extract is literally just the soluble elements found in a coffee bean, minus the caffeine. (This allows the caffeine from new batches to then migrate out of those beans and into the extract.)
I know what it claims to be. At what ratios seem important to me, as not everything in coffee is the greatest for you.

Something that has literally nothing potentially bad for you in it (eg co2 process) seems like it would by necessity be healthier. Again I don’t think any of the processes are actually harmful. Even the scariest MC process (ie dichloromethane) seems perfectly safe to me.

High amounts shrink the brain, increase dementia risk. https://www.tandfonline.com/doi/abs/10.1080/1028415X.2021.19...

And very few people drink 1-2 cups. The travel mugs and typical coffee place cups are close to this danger range.

> After full covariate adjustment, consumption of >6 cups/day was associated with 53% higher odds of dementia compared to consumption of 1–2 cups/day

So what they're saying is too much of a (good? fine? reasonable?) thing can be a bad thing? Not sure this supports a case against caffeine.

You should look up what happens if someone consumes too much salt!

I think my edit addresses your point.
One travel mug is well within the safe range your own link describes...

If people are drinking 3 travel mugs a day... then sure...? Not sure what that changes.

A lot do and I think the brain shrinkage happens even with smaller doses.
> You should look up what happens if someone consumes too much salt!

People are eating too much salt in general - which already has negative impact on health.

Sometimes it feels like if you just abstained from everything, you’d be immortal.
For sure, if you never eat or drink anything you probably won't die of cancer.
I am suspicious of studies that tout “% change in odds” in cases where the odds are pretty low (low enough to be modelled as Poisson) to start with.
so you’re saying that for big brain types the high doses might reduce the risk of brain squeeze, in cases of lack of sufficient space in the brain box.

this is great news.

And if it makes more space for the brain, that should also reduce the risk of concussion. Sounds great to me.
On the other hand, we have Erdős: "A mathematician is a machine for turning coffee into theorems."
Coffee and amphetamines I guess.
"High amounts" is a bit of an understatement, the study is talking about more than 6 cups of coffee daily, which is going to be in the 550-600mg range. Up to about 400mg a day is safe for adults[0]. 600mg is a lot of caffeine. For context, a Bang energy drink which is on the upper end of what you can get in a single drink, is 300mg. Most "energy drinks" are around 200mg less. I'm not sure anyone is surprised by the statement "habitually drinking 3+ energy drinks a day, every day, for an extended period of time, might be bad for you."

[0] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...

Panera Bread was selling lemonade with 390 mg of caffeine in it.

https://www.usatoday.com/story/graphics/2023/12/12/panera-ch...

They're 20 ounces so nearly twice the size of an average drink. Even energy drinks which are typically bigger are usually 16 ounces (though sometimes 20). Looking at the website the highest-caffeine version has just under 160mg in 20oz.

Regardless, not sure what this has to do with the overall point, which is that you could consume multiple "high-caffeine" drinks and still be well under the amounts discussed in this study.

I think you are using energy drinks in your example for effect, only because people overrate their caffeine content relative to coffee. Coffee drinkers who have a full tumbler/togo cup in the morning and a sbux or continual refills from the office pot at work can far exceed the caffeine intake of 3 energy drinks. Meanwhile, Red Bulls actually have deceptively little caffeine and are barely worse than just a regular Coca Cola.

It’s very easy to get into the habit of extremely high caffeine intake, speaking from experience. Not only is caffeine in many drinks and extremely well distributed, its psychological effects are pretty mild. But I think the worst part is that people don’t really think about how much caffeine is in the coffee they’re drinking because it’s hard to measure.

6 cups a day is 48 oz of coffee. A travel mug and venti is 20oz. I don't know anyone who drinks more than 2 of those in a day.

Stop the hyperbole.

A travel mug is more an amorphous volume than simply 20oz.

A Stanley Mug, like the recent Stanley x Starbucks collaboration is 40oz. I believe this may be what they are referring to.

However, it's rare that individuals with the 40oz mugs are filling them with coffee, and if they're with espresso drinks, it's more likely that the volume of milk is increased rather than consuming 8 shots of espresso.

I'd assume most people with travel mugs that consume coffee are using 10 - 16oz mugs like myself?

Some Starbucks orders can compress 4 cups of coffee into one. The MG of caffeine in one of the larger orders can be enormous.
This paper is so ass, it brushes off reduced sleep and then implies it’s caffeine’s fault instead of the user drinking caffeine when they aren’t supposed to.

Shit like this is why nobody trusts science anymore

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Of course non of the paper associations talks about causality, but lack of caffeine is probably a worse overall health association per this paper. More people don’t drink coffee at all than have more than 6 cups a day. From the paper:

“The association between coffee consumption and dementia was non-linear (Pnon-linearity = 0.0001), with evidence for higher odds for non-coffee and decaffeinated coffee drinkers and those drinking >6 cups/day, compared to light coffee drinkers.”

Thank you. It seems rather likely to me that people that are more prone to dementia are more likely to be self-medicating with these very high caffeine intakes. Unfortunately I have only anecdata for this intuition, but if you drink these quantities and/or know anyone with experience with dementia, I think you know what I mean.
"The association between coffee consumption and dementia was non-linear (Pnon-linearity = 0.0001), with evidence for higher odds for non-coffee and decaffeinated coffee drinkers and those drinking >6 cups/day, compared to light coffee drinkers"

So, reading the study, not drinking coffee is bad and drinking more than 6 cups a day is bad too.

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“very few people drink 1-2 cups” - I really doubt this, most people I know drink 1-2 cups.
At least personally, I've found that starting to drink coffee has had a pretty dramatic positive impact on my depression.

I wonder if the difference in experience could come down to the specific circumstances and nature of the issues that someone faces?

You're not going to suggest that different people have different baseline biochemistry and would benefit from different things in different ways? No! That's not allowed! All health advice must fit all people, and people who don't fit the health advice shouldn't be allowed to complain about it.

/sarcasm, but I've seen serious versions of this argument

I do think it would be nice if we had health advice that applied to all people.
Do at least moderate amounts of exercise fairly regularly.
Take your tetanus shot and don’t step on rusty nails. But, per GP’s point, maybe someone doesn’t get tetanus anyway.
> maybe someone doesn’t get tetanus anyway

Isn't that what the vaccine is for?

It's still a good idea to not step on dirty rusty nails. There are no exceptions here.

I keep seeing versions of the argument that we’re all unique snowflakes and so all science is bad and all advice is untrustworthy bs. Usually the argument feels more like a variation on ‘you’re not the boss of me’ than a serious discussion of the science. This feels especially common to me when discussing diets; people seem to get pretty defensive whenever some advice or outcome has any way of being interpreted as that person potentially having less than perfect behavior.

I don’t know what ‘people have different baseline biochemistry’ really means. Approximately zero humans survive on sulphur and chlorine in place of nitrogen and oxygen. This argument tends to overlook the fact that people are mostly similar, and there’s enough of us that we have decent data on how similar we are. Humans are all approximately the same construction, and have approximately the same reactions to most things. It’s true there’s tons of minor variability for some things, but no serious science or health advice that will fail to mention or acknowledge that variability. My advice (which may or may not work for you) is to ignore people who say health advice must fit all people… and also ignore people who say that no advice will work for them, or even that advice that works for most can’t work for them without trying it first.

I feel like a good default assumption is that something that works for the average person will probably work for me too, so try it first, and then look for alternatives if/when I find out it’s not working. This is still a good default assumption even when accounting for the ‘flaw of averages’ (cf. the Air Force story about cockpit design) - most of us will fit the the average for most things, even while at the same time most of us will be outliers for some things.

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Subtweeting the Eliezer Yudkowsky threads on weight loss? More seriously, yes, "We're all unique so nothing could possibly apply to me" is usually pretty thinly veiled cope.
> I keep seeing versions of the argument that we’re all unique snowflakes and so all science is bad and all advice is untrustworthy bs.

I keep seeing people take statements that are valid within reason to the extreme.

In broad strokes, most things about humans are true, but there is certainly nuance and variation between people. Probably because we don't fully understand the things we think we do.

It's probably best to treat the articles like these (and the dietary advice in general) as an invitation to experiment and see how it works for your particular case, not as a definitive statement that "X is good for everyone always, Y is bad for everyone always"
Depends what type of depression you have. Like "my life sucks" depression or "metabolic health is bad" depression or both.
Since we're exchanging anecdotal evidence, I also feel better with coffee. It lets me control how energized I am. Helped me avoid burnout and generally makes me feel a bit better no matter how much I take.
If it helps you it's great. I was drinking tons of coffee daily from my teenage years to my mid-20s. I didn't feel any ill effects from it. Now in my early 30s, it causes anxiety. I don't know how or why, but it's scary how caffeine and a little bit of tiredness turns me into a shell of a man these days. Having a safe stimulant to kick you out of inactivity is a great help so I'd say take advantage of it.
Coffee is an anti-depressant. AFAIK it increase serotonin and dopamine levels so is not all that different from a lot of antidepressant drugs.
> At this point, many of you might be thinking: Zan, you sneaky weasel. Haven't you just cherry-picked your redditors and scientific publications to fit your narrative?

Adressing it is good, but ultimately it does not really act as a rebuttal, this is a biased collection of anecdotes from a subreddit of people drinking decaf.

That being said, if you do feel like your anxiety is always high and that you have a trouble sleeping, it's probably worth stopping and assessing, a bit like how people with IBS will just periodically remove things from their diet to see its impact.

A lot of dietary science is shaky, and I think we should accept that different people respond to various psychoactive substances differently. I don't have any reason to question the author's conclusions, nor doubt that others might have the same experience - even if it doesn't quite jibe with mine (I'm in this camp: https://twitter.com/danielcrosby/status/1534584565431296001).

What doesn't sit with me is that the article makes a lot of hyperbolic claims ("Caffeine is literally killing your dreams", etc) and says a lot of sciencey-sounding stuff, but then wraps it up with "no, you can't cricitize that":

> Q: Don't you care? Don't you think it's misleading?

> A: Nah. I'm not writing a philosophical treatise here. I'm not writing a lawsuit to take all coffee lovers to court. And I'm definitely not writing a scientific review.

I mean, OK, it's your blog - but you're trying to have it both ways. If you wanted to write about your subjective experience, fine. But you're making it seem as if you're presenting settled science.

Agreed. Also, like all drugs and food in general, we all respond very differently to them, have different habits, different associations and different relationships with them. I personally had to quit alcohol, coffee and weed when I was battling a year-long stomach issue. I'm now on the other side and can confidently say that not drinking coffee was a net negative for me. I didn't feel more alert, I didn't sleep better and I didn't feel less anxious. In fact, I was generally much less alert and productive. My coffee habit is more or less where it was before my health issues. Alcohol wise, I'm also back at the same frequency but much lower volume. I like it but found that my perfect amount is 2-3 drinks, not 5-6. Finally for weed I've not gone back to it. It made me anxious and I don't miss it.

If someone else had gone through my experience, they may have come back to a completely different distribution of usage. And in fact I know many people who do various combination of the 3 because of the way each affects them. We're all different.

It’s fine if you’re bugged by the writing or argument style, but there is plenty of solid science on the side-effects of caffeine. It’s interesting that you criticize the author for being unscientific and then share a hyperbolic twitter anecdote and cast unsupported FUD on the science. The good science that we have always acknowledges that people respond differently, and yet we usually clump into a normal-ish distribution where the vast majority of people have very similar experiences, and we can quantify how similar and how often, and sometimes why there are deviations. Failing to acknowledge the similarities is as bad as failing to acknowledge the differences, scientifically speaking.

https://medlineplus.gov/caffeine.html

https://en.wikipedia.org/wiki/Caffeine#Adverse_effects

You can also just lower the dose instead of following this black and white “am I a drinker” thinking. A single (1/2 double) espresso in the morning is not so much.
That's what I'm thinking as well. I have 2 espressos per day and I don't get anywhere close to the state when I drink a single black coffee from <big chain>.

Not all coffees are the same. Some types of drip coffees (such as Tim Hortons) make me wonder if it's laced with cocaine.

I only use Caffeine now when I'm really low on sleep and stop all intake after that. In high school, I would drink tons of caffeine every day.

I didn't realize until later in life that it contributes to my anxiety. I sleep much better without it and can actually get more work done. My anxiety is also reduced to almost nothing.

I think I got into a habit of just drinking coffee every day, that I didn't really think about it.

Important to note: Not everyone has the same reaction to caffeine. And not all caffeine hits the same. What it’s mixed with matters.

The caffeine in tea, for example, doesn’t have as many anxiety inducing effects because you also get a bunch of L-theanine, which has a calming effect. To the point that many modern energy drinks have started adding it to their formula.

Personally I sleep fine with or without caffeine. Timing matters little. What really absolutely truly impacts my quality if sleep – physical activity.

Can't underscore how much better you sleep if you've done a good amount of physical activity. Truly nothing is better than lying down after a day of physical labor.
Or physical playing. You don’t need to make it drudgery to get the benefits :)
I don't drink caffine on a daily basis but some weeks I do.

One of the big things for me is coffee is not a good one to drink. The caffeine in it may wake me up but it does not fix anything else so I find myself in a state that is best described as really bad morning person for the entire morning. I may be awake but I have essentially a tension at the base of my head and feel essentially hangry without the hunger.

Energy drinks (Redbull or aussie lemonade monster) wake me up much more mellow. I have thought a few times about trying to figure out what else is helping. Its not the sugar as the coffee has plenty.

These articles always tell me I’m doing too much or not enough.
Drink more red wine! Drinking any red wine at all will kill you! Replace water with red wine! Just looking at red wine linked to spontaneous combustion!!!
I quit Coffee one month each year (Ramadan while fasting). It has the effect of resetting my tolerance to caffeine. The first coffee after Ramandan feels more like Cocaine than Caffeine, almost like a superpower. However, I have to say, I don't see any difference in sleep quality with or without coffee. I just make sure only to drink coffee in the morning.
Doesn't that make the first few days of fasting miserable? Have you tried progressively reducing the dosage for a few weeks in preparation?
Isn't subjecting oneself to feeling miserable kind of the point of religious fasting?
I've fasted for an entire day a few days at a time, it didn't really make me feel miserable.
Not really, and you would be surprised that you feel more of a lightness, clarity and not miserable. It's the same for running, it's hard, but you don't feel miserable when doing it.
Yes, I fast for Ramadan and about a week beforehand switch to decaf for all my hot beverages.

When I didn't the headaches were terrible in the first few days of fasting.

I do exactly that. Usually I quit one week before Ramadan. When quitting, it's common to get headaches. When quitting before Ramadan, you can alleviate it with a bit of Aspirin.
After a decade of a cup or two a day, I switched to decaf, and then stopped that too.

I had no idea, but it wasn’t until I stopped that I realized I had been living life through a fog… kind of dulled down senses and reactions.

I love coffee, but I feel so much better without it I’ll never go back. I highly recommend everyone quit just to see how they feel. You might be surprised

This isn't really against caffeine, it's against drinking multiple cups of coffee throughout the day. Tea is less anxiety-inducing that coffee (and lower in caffeine). Even if you stick with coffee, a cup in the morning won't mess with your sleep unless you are unusually sensitive.
I think it's good to examine all habits that we have, and if this article gets you to consider the (potentially unknown) trade offs you're making, great!

but to really know what they are, RCT self-experiments are the best way to work out what's really going on.

gwern has a bunch of examples (https://gwern.net/zeo/caffeine) but you should tailor yours to the effects you're most interested in.

incidentally, does anyone here have a go-to tutorial for how to set one up, how to do power analysis, etc? i'm persuaded by why we should do RCTs, but I don't have the background in statistics to confidently run them myself.

I quit booze a few years ago. It's a 10x improvement on my life. Quitting caffeine is probably not a 10x'er, but seems worth a go.
anecdotally I have taken breaks from both and taking a break from alcohol seems far more beneficial
I had a very similar experience as this author. All throughout high school and college, I was prescribed Adderall. After graduation, I got a job, and realized Adderall wasn't good for me long term, so I switched to coffee. This alone helped with my anxiety, ability to sleep, and social interactions.

After a while, I started to wonder if coffee is good for me also. So I quit cold turkey for a few weeks as an experiment. I couldn't believe the effect it had. I am angry at myself that I didn't just do this earlier. I sleep fine all night now, I don't have to pee as often, my anxiety is basically gone, I feel better about life in general, my brain fog disappeared, and I no longer have "good days and bad days" mentally, just good days.

There is no more powerful drug or therapy in the world than:

1) Exercising regularly.

2) Eating healthy.

3) Quitting the stimulants.

How much did you drink? I found the same effect when I didn't know how to use coffee and drank at any hour, multiple times a day, from the office's coffee machine, and couldn't make it at home. Obvious result: bad sleep, anxiety, and a crash every weekend. They all got better after I quit, also obviously.

Then I looked into it more, bought my own press and grinder, started taking one cup a morning with the dosage I want, occasionally a small extra but nothing after 2PM. The effect is pretty nice. On average, I feel a bit better with it than without.

I started out drinking a lot, usually 2 cups per day, one at breakfast and lunch. But eventually I just weaned myself down to one cup at breakfast for a few years, and I was still having trouble sleeping.

I feel like caffeine is a *results may vary topic, every time it is discussed many people have wildly different experiences.

Why were you on Adderall? ADHD? Personally I'd struggle to not have any stimulants even if I could have less.
Tangental but as someone who used to have sleep issues but has no intention of ditching coffee, taking Magnesium L-Threonate has utterly transformed the quality of my sleep. Used to wake up a ton in the night, take forever to get to sleep, etc. and now I sleep extremely well and if I'm up in the night it doesn't take me long to get back to sleep.
Is it any better than magnesium citrate?
The sales pitch the manufacturers give is that L-Threonate is better at getting through the blood/brain barrier so it is more effective for stuff like sleep. I do notice a difference between that and when I just take Magnesium Chloride but I haven't tried citrate so I don't know.
I wish this was initially disclosed as an opinion piece rather than reading through it and finding it out in the end.
Some comments about dietary science are true. It is extremely impossible to isolate the effect of a single substance (ethically).

This person greatly benefited from stopping caffeine intake which is great. It is part of the journey to understand ourselves and what makes us work/improve/feel better.

If you have a anxiety-o-meter that looks like this: [-----------------------------------]

and your baseline is here: [-------------------------X---------] - you just need a little push to go into anxiety/can't sleep mode which can come from caffeine.

But if your baseline is around here: [--x--------------------------------] -maybe some coffee in the morning, right after lunch will greatly increase your clarity/make you able to fulfill your duties. People who drink caffeine for pleasure (I love the taste of coffee and sometimes I get beans so good that I just want to drink several cups) will notice the negative effect in their sleep/anxiety levels. We must go back to Paracelsus 'dosis sola facit venenum'. The dose makes the poison.

I've been on the decaf wagon for a good few years now, I can't say it helped me out with anxiety or productivity but I can echo the sentiment that I can sleep within minutes. Also not relying on caffeine to keep me going pretty much forces me to sleep at a reasonable time.

The hardest thing about giving up caffeine has to be the immediate effects. Your body takes it as a massive shock and you're stuck with what feels like a migraine for 2 days. Not fun.

I know decaf still has some caffeine in it, but it's a compromise for something different – for a month of cold turkey I thought I had cravings for caffeine, but it turned out it was hot drinks I was after. I think it's the one luxury I couldn't be without.

> Your body takes it as a massive shock and you're stuck with what feels like a migraine for 2 days. Not fun.

Yup, but you can wean yourself off gradually and it's fine. I've done it several times -- just reducing it by 10% of your original amount each day, so you spread the effect out over 10 days. At least for me, zero headaches.

Not gonna lie though -- there is a generalized feeling of a little bit of extra "grogginess" each day. But much less than if you've come down with a cold, for example. And it's far less painful than going cold turkey.

Because you're right -- otherwise the 2-day migraine is awful.

I quit cold turkey and had bad headaches. What helped for me was having a decaf coffee. Just one would make the headaches go away. So the jump from say 300 mg to 10mg of caffeine was somehow much better than 300 to 0.
>And it's far less painful than going cold turkey.

As stupid as it sounds I forgot that it was an option. There's something clean about saying "I won't have any more of X after this date" and sticking to it. Although I could've tapered off beforehand!

I stuck with 7 or so months of dandy blend and roibos to make sure it wasn't just an addiction to the caffeine - and I eventually came back to decaf coffee. The problem is I want hot drinks with body and complexity - and dandy blend comes close, but is so flat compared to a coffee or a black tea. :(
I think tapering off caffeine is a lot more gentle than going cold turkey. And if you are in a hurry for whatever reason, plan to have one ~50mg dose on day three or four when the headache gets distractingly bad. You can use Tylenol Ultra Relief or Excedrin Migraine if you don't want to deal with coffee or soda. That should get you over the hump with minimal disruption.
The mistake that people make is that they expect to be 100% wired the second they get up from bed, while in actuality it takes an hour a two for the (enzyme that wakes you up) to start being produced in your body.

Also: caffeine doesn't make you more alert, it just borrows alertness from the future by blocking the receptors where Adenosine attaches to. The enzymes are still produced, they're not going anywhere.

a cup of decaf has less caffeine than an ounce of dark chocolate. lots of things have caffeine; it's a naturally-occurring substance.

i also got headaches when i quit caf coffee, though i didn't realize that it was because of that at the time.

Seems like the author is a slow metabolizer like me. Interestingly enough, it seems that the caffeine half life can be shortened by eating broccoli (https://pubmed.ncbi.nlm.nih.gov/17266520/) - by having coffee in the mornings and broccoli with dinner I've been able to enjoy the mood boosting effects of caffeine during the day and still be able to sleep fine.

Sleep quality aside though, I thought my anxiety was due to stressful job, but maybe it's due to all the caffeine I have in an attempt to be productive.. perhaps something to experiment with myself.

Thanks for sharing, even the remote chance that it works for me makes it worth trying
A lot of the back and forth in this thread seems to be overlooking the glaring fact that caffeine's half-life varies from 2 to 12 hours depending on the person. Getting to 90% elimination could take one person ~6 hours and another person ~36 hours.

This, on top of the fact that caffeine has been shown to increase cortisol secretion and adrenaline, as well as boosting the effects of dopamine and norepinephrine in the brain, should give a very clear indication that caffeine is going to have drastically different effects from person to person.

Anyone who is struggling with sleep, anxiety, and/or mood disturbances should consider reducing or eliminating caffeine for several weeks to see if it helps. Don't expect it to be a magic bullet to solve all problems, just like anything else. Bodies are complex, and when we are chronically suffering from sub-optimal functioning, it's a good bet that their is some complicated and highly variable biochemistry going on that's keeping the body from homeostasis / optimum function.

> If coffee decreases the possibility of myocardial infarction and it is no longer harmful from a carcinogenicity point of view, it is the time to acknowledge Gustav III (1746-1792 CE) (Encyclopædia Britannica, 2016 ▶), the adventures king of Sweden’s, pioneer experiment on coffee safety as the first documented “randomized clinical trial” in medical history.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5355814/