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The effects of caffeine consumption do not decay with a ~5 hour half-life

89 points by swah

by keepamovin

3 subcomments

I take pentoxyfylline (a synthetic substituted xanthine, caffeine is a natural substituted xanthine) occasionally as a nootropic and supplement for vascular health and anecdotally for me it has several nice caffeine like properties without the jitters/ long tail, sleep effects etc.
I find the listed side effects don’t happen for me besides occasional flush/blush. Which at my age is more like youthful vigor.
Caffeine is is 1,3,7-trimethylxanthine, pentoxyfylline is 3,7-dimethyl-1-(5-oxohexyl)xanthine.
Good effects are: sustained mental clarity, focus and energy with a smoother more stable baseline than caffeine’s bursty performance; good sleep, but strangely you can also stay up, if you prefer; feeling similar to “after exercise”. Half life is listed as under 1 hour, but beneficial effects can be felt for half a day after 400mg (a standard dose). So maybe there’s something like metabolite dynamics occurring here too.
This ends my erowid/hive style “trip/nootropic” report ;)

by drakonka

1 subcomments

I think it is already pretty widely recognized that caffeine can disrupt sleep taken even as early as 6 or 7 hours before bed. I usually don't drink coffee or caffeinated tea after 12 for this reason. Caffeine also has many other known benefits, possible beneficial effects on all-cause mortality, etc, and I'm not sure if we have any research showing the same benefits coming from paraxanthine. Seems like potentially a bit of a waste just to be able to get the stimulant effect a couple of hours closer to sleep time.

by bensyverson

5 subcomments

This article makes the case for paraxanthine supplements; 80% of caffeine is metabolized into paraxanthine anyway, and it turns out paraxanthine behaves a bit more like we (apparently wrongly) assume caffeine works.
But the real question is: does it taste as good as espresso?

by georgewsinger

0 subcomment

I'm surprised the author didn't mention the other argument for paraxanthine being less addictive than caffeine: it has a less acute/peaky curve of adenosine blocking.
I'm not a biologist, but I'm under the impression that your body uses the heuristic of "the more acutely a neurotransmitter is suddenly flooded into our system, the more of a homeostatic counter-response we're going to launch in the form of things like dopamine downregulation (etc, depending upon what neurutransmitter we're talking about)".
I'm not entirely sure this is true, but it seems to be corroborated by other researchers (e.g. Anna Lembke in her book Dopamine Nation, which isn't about caffeine though).
This is why substances like theacrine claim to offer even less tolerance than paraxanthine: it has a super gradual adenosine-blocking curve, with super long half-life (like 12-16 hours, IIRC). So when you take one theacrine, you won't notice it for hours, but its effects will last longer than one day (though I forget what its interaction with sleep is supposed to be?).

by cjbgkagh

1 subcomments

There are some fairly common genes that can drastically effect the strength and duration of caffeine so your experience may vary. For me the effect is very strong and one cup lasts all day, even as a habitual consumer.

by bembem_c

0 subcomment

Pharmacokinetics (in this case: half-life in the central(venous) compartment, totally neglecting the distribution to the site of primary activity, the CNS) is only half of the truth.
You have to consider pharmacodynamics: where is the site of action located, where are the receptors located. And how well do caffein and paraxanthine distribute to this compartment.
Soiler: Most metabolites are more hydrophilic than respective parent compounds (biological sense of metabolism: to increase renal clearance of xenobiotics). Therefore, receptor affinity alone tells you little about the relative contribution of any metabolite for the pharmacological effect observed.
And to complicate things even more: Long-half life metabolites are only ONE potential reason for prolonged biological effects.

by blitzar

1 subcomments

Its like a 45 minute decay - Im not shaking the cup's shaking. I can quit anytime I want, I just dont want to.

by sharpshadow

1 subcomments

Fun fact smoking reduces caffeine half-life up to 50% by upregulating the enzymes which break it down, which affect paraxanthine as well.

by uticus

0 subcomment

> Importantly, the primary metabolites also block adenosine receptors.
Biochemistry is rarely a one-and-done event it would seem.

by charles_f

0 subcomment

That's an interesting takes. I found it quite suspicious at first, especially because it doesn't present well the myths that it's trying to debunk: are we talking abouy caffeine half life or its effects; and is that 5h half life related to the metabolism of caffeine, or related to its effects.
It looks like pharmacokinetics (ie how long caffeine stays in blood) is what's been studied mostly, and that's where the 5h timeline is coming from. I couldn't find papers on the timeline of pharmacodynamics of caffeine (how long it has effects).
That's an interesting gap this article is underlining!

by NoiseBert69

2 subcomments

For me a coffee is more kind of a ritual addiction.

by meitham

1 subcomments

I haven’t come across lesswrong before! Great site and this caffeine article is great presentation of data.

by siliconc0w

1 subcomments

Nicotine is also a nice alternative to coffee. I still drink coffee but past late morning I'll usually reach for nicotine because the effect is much shorter.
It also has neuro-protective effects if you're an older gentleman.

by mannyv

0 subcomment

FYI you can't patent a supplement. You can, however, be the only manufacturer because nobody else noticed it.

by michaelcampbell

1 subcomments

This feels like a Gwern blog, or something he'd be interested in.

by insane_dreamer

0 subcomment

I used to drink two double-espressos (technically a latte with a double-espresso in it) a day -- one in the morning, one early afternoon -- for many years.
~5 years ago I stopped drinking the afternoon coffee, and have subjectively noticed improvements in my sleep -- less wakeful in the night. It also fits better with my sleep habits, where when I was younger I commonly worked past midnight whereas now I'm asleep by 10 pm and wake up early.
I still drink the morning coffee and I wouldn't switch to another stimulant because the main reason I drink coffee is because I enjoy drinking coffee :)

by atlgator

0 subcomment

I generally avoid caffeine at all costs. I'm susceptible to SVT, and I want the Adenosine to work if I should need it. Caffeine blocks Adenosine receptors. But on the rare occasion I have a single can of caffeinated Diet Coke, I experience a crash 48 hours later so profound that I cannot get out of bed that day.

by annoyingnoob

0 subcomment

Why change what works? Especially if you enjoy it.

by fredgrott

0 subcomment

sight correction....caffeine impacts two neuron groups not just one!
Dopamine and Noradrenaline
For dopamine its the competitive for the adenosine part of the dopamine heretodimer....meaning it prevents adenosine from binding and closing the dopamine receptor....
I use the effect on both dopamine and noradrenaline to assist in controlling my ADHD via more herb based means....
But author is yes correct that the metabolism of caffeine in how it breaks down does make the half life of its effects longer than 5 hours...I combine my dose with green tea ECGC which gives me a good focus boost of 12-16 hours...