Coffee, caffeine, and sleep — practical, science-backed reads from CaffIQ.https://caffiq.app/en-UShttps://caffiq.app/articles/nespresso-caffeine-content/https://caffiq.app/articles/nespresso-caffeine-content/An Espresso capsule holds 55–65 mg of caffeine, a Lungo 77–89 mg, and a large Vertuo up to 200 mg. The real figures, range by range.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/pods-vs-ground-coffee-caffeine/https://caffiq.app/articles/pods-vs-ground-coffee-caffeine/France's ANSES measured 150 mg per 100 ml in a capsule against 50 mg in filter coffee. But in the cup the ranking flips — here is why, format by format.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/lungo-vs-espresso-caffeine/https://caffiq.app/articles/lungo-vs-espresso-caffeine/A lungo capsule holds 77–89 mg against 55–65 mg for an espresso. But stretching an espresso capsule with the button adds almost nothing. Here is why.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-shop-espresso-caffeine/https://caffiq.app/articles/coffee-shop-espresso-caffeine/An espresso served across a counter runs 60 to 80 mg — usually the top of that range. What is really in the cup, and why two cafés never match.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/ristretto-vs-espresso-caffeine/https://caffiq.app/articles/ristretto-vs-espresso-caffeine/Yes, slightly — and it is the opposite of what it tastes like. Between a ristretto and a long shot the real gap is about ten milligrams.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/chicory-coffee-caffeine/https://caffiq.app/articles/chicory-coffee-caffeine/Chicory root itself has none at all. But most drinks sold as chicory are blends — and one popular one carries 64 mg a cup, as much as an espresso.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/anses-caffeine-guidance/https://caffiq.app/articles/anses-caffeine-guidance/The French food-safety agency sets no maximum dose. It measures what people actually drink, and rules on two specific pairings. Here is the detail.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-before-blood-test/https://caffiq.app/articles/coffee-before-blood-test/Labs define fasting as nothing but water — coffee is outside it, even black. What they ask for, and why the answer changes with the test.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/red-bull-caffeine/https://caffiq.app/articles/red-bull-caffeine/80 mg in the 250 ml can, 114 mg in 355 ml, 151 mg in 473 ml. The concentration never changes — the size decides, not the recipe.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coca-cola-caffeine/https://caffiq.app/articles/coca-cola-caffeine/About 34 mg in a 355 ml can, roughly a third of a coffee. And Diet Coke holds more than the classic — 46 mg. The figures, variant by variant.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/bean-to-cup-caffeine/https://caffiq.app/articles/bean-to-cup-caffeine/A bean-to-cup espresso holds 70–90 mg against 55–65 for a capsule. The gap is the dose of grounds — and that is the one you set yourself.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/decaf-capsule-caffeine/https://caffiq.app/articles/decaf-capsule-caffeine/Nearly, not quite: 3–6 mg in an Original capsule, up to 11 in a Vertuo. Ten to twenty times less than a regular capsule, without being zero.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/instant-coffee-caffeine/https://caffiq.app/articles/instant-coffee-caffeine/About 30 mg per level teaspoon, so around 60 mg for a two-spoon cup. The real variable isn't the brand — it's your hand.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-with-dessert-sleep/https://caffiq.app/articles/coffee-with-dessert-sleep/An espresso served with chocolate petits fours is 70–100 mg, not 60–80. And it arrives at the most expensive hour of the day.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/milk-coffee-drinks-caffeine/https://caffiq.app/articles/milk-coffee-drinks-caffeine/It holds none and removes none. A cappuccino and a macchiato weigh the same: 60 to 80 mg. Only the number of shots counts.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/high-caffeine-content-label/https://caffiq.app/articles/high-caffeine-content-label/A mandatory statement above 150 mg per litre. But an espresso runs at 1,500 mg/L and carries nothing — because the rule sorts by category, not by dose.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-and-ramadan/https://caffiq.app/articles/coffee-and-ramadan/The first-days headache is caffeine withdrawal, not hunger. What pharmacology says about the night window and the pre-dawn meal.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-and-long-drives/https://caffiq.app/articles/coffee-and-long-drives/Caffeine masks fatigue, it doesn't remove it. Why a coffee taken too late arrives after the fact, and why the coffee nap is the one combination that works.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/monster-caffeine/https://caffiq.app/articles/monster-caffeine/160 mg in the 500 ml can. The same concentration as a Red Bull — 32 mg per 100 ml — so the can size is the entire difference.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/starbucks-caffeine/https://caffiq.app/articles/starbucks-caffeine/From 75 mg for a latte to 410 mg for a venti brewed coffee. Black coffee climbs highest — and going up a size doesn't always add coffee.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/restaurant-decaf/https://caffiq.app/articles/restaurant-decaf/Yes — 'decaffeinated' is a regulated category, not a marketing claim. Reckon on 5 to 15 mg in the cup against 60 to 80 for a regular coffee.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-doping-status/https://caffiq.app/articles/caffeine-doping-status/No: WADA removed it from the Prohibited List on 1 January 2004. It stays on the Monitoring Program, which is not remotely the same thing.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/energy-drinks-minors-law-france/https://caffiq.app/articles/energy-drinks-minors-law-france/Contrary to widespread belief, no French law bans selling them to minors. What does exist: a mandatory label and a ban inside schools.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-guidelines-compared/https://caffiq.app/articles/caffeine-guidelines-compared/Everyone agrees on 400 mg a day. The divergences are elsewhere — and the trap is that a US 'cup' is 355 ml, not an espresso.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/all-nighter-caffeine/https://caffiq.app/articles/all-nighter-caffeine/It restores alertness, not memory. And sleep is what fixes what you just learned — which is the problem with revising through the night.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-in-hot-weather/https://caffiq.app/articles/coffee-in-hot-weather/Heat changes almost nothing about caffeine. What changes is the format: switching from espresso to iced coffee can triple the dose unnoticed.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/split-shift-caffeine/https://caffiq.app/articles/split-shift-caffeine/Two services, two peaks of alertness, and a 1 a.m. bedtime. 'Nothing after 2 p.m.' stops meaning anything — here's what to anchor the last coffee to.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/mid-morning-coffee/https://caffiq.app/articles/mid-morning-coffee/Yes, one of the best of the day. Not for cortisol reasons: because twelve hours remain before bed. The awkward moment is 4 p.m.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/bottled-iced-tea-caffeine/https://caffiq.app/articles/bottled-iced-tea-caffeine/Yes, but very little: about 4 mg per 100 ml, so roughly 14 mg a bottle. Four to five times less concentrated than brewed tea.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/guarana-sodas-caffeine/https://caffiq.app/articles/guarana-sodas-caffeine/Not hidden, just differently named: guarana's caffeine isn't called caffeine on the label. In a soda it stays very low all the same — 10 to 15 mg.Sat, 15 Aug 2026 00:00:00 GMThttps://caffiq.app/articles/swiss-water-vs-ea-decaf/https://caffiq.app/articles/swiss-water-vs-ea-decaf/Swiss Water, sugar cane EA, CO₂ or methylene chloride? How the decaf methods compare on taste, chemistry and safety — and how to pick the best decaf.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/what-is-half-caf/https://caffiq.app/articles/what-is-half-caf/Half-caf is part regular, part decaf — about 45–50 mg of caffeine a cup instead of 95. What it is, the caffeine math, how to make it, and when to reach for it.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/dark-roast-vs-light-roast-caffeine/https://caffiq.app/articles/dark-roast-vs-light-roast-caffeine/No — roast level barely changes caffeine. Why 'strong' isn't 'caffeinated', the scoop-vs-weight twist behind the myth, and what really drives your dose.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/robusta-vs-arabica-caffeine/https://caffiq.app/articles/robusta-vs-arabica-caffeine/Robusta has about twice the caffeine of arabica — roughly 2.2–2.7% vs 1.2% by weight. Why, how they taste, where each shows up, and what it means for your cup.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/brew-method-and-caffeine/https://caffiq.app/articles/brew-method-and-caffeine/Yes, but mostly through dose and contact time, not magic. How grind, heat, steep and ratio shape your cup — and how the common brew methods compare.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/how-much-caffeine-in-tea/https://caffiq.app/articles/how-much-caffeine-in-tea/A cup of tea has ~20–70 mg of caffeine — less than coffee. The mg by type (black, green, white, oolong), what changes it, and the tea-vs-coffee myth.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/yerba-mate-guarana-natural-caffeine/https://caffiq.app/articles/yerba-mate-guarana-natural-caffeine/Caffeine is the same molecule whatever the plant. Yerba mate, guarana, cacao, kola & more — the mg, and why 'natural' doesn't mean gentle.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-coffee-sober-you-up/https://caffiq.app/articles/does-coffee-sober-you-up/No — coffee makes you feel alert but doesn't lower your blood alcohol. Why 'wide-awake drunk' is dangerous, and what actually sobers you up (only time).Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-coffee-stunt-your-growth/https://caffiq.app/articles/does-coffee-stunt-your-growth/No — there's no good evidence coffee stunts growth. Where the myth came from, what really sets your height, and what actually matters for kids and caffeine.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/get-rid-of-caffeine-jitters/https://caffiq.app/articles/get-rid-of-caffeine-jitters/No instant antidote — only time — but you can take the edge off in minutes. Stop, hydrate, eat, walk, breathe: what works, and when to get help.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/why-does-coffee-make-you-poop/https://caffiq.app/articles/why-does-coffee-make-you-poop/For about a third of people, coffee triggers the urge — often within minutes. And it's mostly not the caffeine: decaf does it too. Here's the real reason.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-on-an-empty-stomach/https://caffiq.app/articles/coffee-on-an-empty-stomach/For most people it's fine — no, it won't ruin your stomach. But coffee raises acid, and without food some get reflux, nausea or stronger jitters. What to do.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-intolerance-or-allergy/https://caffiq.app/articles/caffeine-intolerance-or-allergy/A true caffeine allergy is real but rare. What most call 'intolerance' is high sensitivity — from your genes. How to tell them apart, and what to do.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-caffeine-raise-blood-pressure/https://caffiq.app/articles/does-caffeine-raise-blood-pressure/Yes — caffeine causes a small, temporary rise, usually a few to ~10 mmHg. Why it happens, whether it lasts, and who should be careful. Not medical advice.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-and-acid-reflux/https://caffiq.app/articles/coffee-and-acid-reflux/For some people, yes — coffee can relax the valve above your stomach and raise acid. Why it happens, whether decaf helps, and how to drink with less heartburn.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/why-caffeine-doesnt-affect-you/https://caffiq.app/articles/why-caffeine-doesnt-affect-you/Some people barely feel caffeine — usually tolerance, fast metabolism or their genes. But here's the catch: not feeling it doesn't mean your sleep is safe.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/men-women-caffeine-metabolism/https://caffiq.app/articles/men-women-caffeine-metabolism/Yes — but it's hormones, not sex. The pill roughly doubles how long caffeine lasts and pregnancy slows it more. What changes, why, and what it means.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/how-long-to-build-caffeine-tolerance/https://caffiq.app/articles/how-long-to-build-caffeine-tolerance/Caffeine tolerance builds within days and firms up over 1–2 weeks — and a 1–2 week break resets it. The timeline both ways, and how to keep caffeine working.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/wake-up-at-night-after-coffee/https://caffiq.app/articles/wake-up-at-night-after-coffee/Fall asleep fine but wake at 3am? Caffeine's long tail lightens your sleep and makes you surface in the second half of the night. Why, and how to fix it.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-caffeine-affect-rem-sleep/https://caffiq.app/articles/does-caffeine-affect-rem-sleep/Yes — caffeine can reduce and delay REM, the dreaming, memory stage. How it differs from its hit to deep sleep, and why evening coffee targets it.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/what-is-caffeine-how-does-it-work/https://caffiq.app/articles/what-is-caffeine-how-does-it-work/Caffeine is a natural stimulant that blocks adenosine, the chemical that makes you sleepy — so it masks tiredness rather than adding energy. The full explainer.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-caffeine-improve-focus/https://caffiq.app/articles/does-caffeine-improve-focus/Yes — caffeine sharpens alertness, vigilance and reaction time, most when you're tired. But there's a sweet spot: too much wrecks focus. How to use it well.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-cortisol/https://caffiq.app/articles/caffeine-and-cortisol/Yes — caffeine can modestly raise cortisol, but the rise is small and regular drinkers build tolerance. The morning-timing myth, and whether it matters.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-caffeine-boost-metabolism/https://caffiq.app/articles/does-caffeine-boost-metabolism/Yes — caffeine gives metabolism a small, temporary boost and nudges up fat burning. But it's modest, fades with tolerance, and isn't a weight-loss shortcut.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-coffee-break-a-fast/https://caffiq.app/articles/does-coffee-break-a-fast/For most fasting goals, black coffee doesn't break a fast — it's near-zero calories. What does: milk, sugar, cream, syrups and butter.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-and-migraines/https://caffiq.app/articles/coffee-and-migraines/Caffeine can both help headaches (it's in many painkillers) and trigger migraines (too much, or missing your usual dose). Why moderation and consistency matter.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-menopause/https://caffiq.app/articles/caffeine-and-menopause/Caffeine can make some menopause symptoms harder — hot flashes, sleep, anxiety — for some women. What the research suggests, and how to enjoy coffee anyway.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/is-coffee-bad-for-your-heart/https://caffiq.app/articles/is-coffee-bad-for-your-heart/For most healthy people, moderate coffee isn't bad for the heart — studies don't link it to heart disease. The real effects, and who should be careful.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-jet-lag/https://caffiq.app/articles/caffeine-and-jet-lag/Caffeine can help beat jet lag — if you time it to the destination clock. Morning coffee keeps you alert; a late cup wrecks your reset. How to time it right.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/cut-back-on-caffeine-without-headache/https://caffiq.app/articles/cut-back-on-caffeine-without-headache/Cutting caffeine suddenly causes the headache — so taper gradually instead. Use half-caf and decaf to ease down, keep the coffee you love, and skip the pain.Mon, 13 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/birth-control-and-caffeine/https://caffiq.app/articles/birth-control-and-caffeine/Estrogen in the combined pill slows caffeine's clearance, so its half-life roughly doubles — your coffee lingers longer and reaches into your night.Sun, 12 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-exercise/https://caffiq.app/articles/caffeine-and-exercise/Caffeine is a proven performance aid at ~3–6 mg/kg taken 45–60 min before. The catch: an evening pre-workout has a long tail that can cost your sleep.Sun, 12 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-teens/https://caffiq.app/articles/caffeine-and-teens/No official safe caffeine level is set for teens. EFSA references ~3 mg/kg a day, energy drinks are the main concern, and teen sleep makes timing matter.Sat, 11 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-breastfeeding/https://caffiq.app/articles/caffeine-and-breastfeeding/Only a small amount of caffeine passes into breast milk. Many authorities cite moderate intake as generally fine — with newborns the sensitive case.Fri, 10 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-pregnancy/https://caffiq.app/articles/caffeine-and-pregnancy/Authorities commonly cite ~200 mg of caffeine a day in pregnancy. What the reference means, why clearance slows, and why your doctor guides your number.Fri, 10 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/wait-90-minutes-first-coffee/https://caffiq.app/articles/wait-90-minutes-first-coffee/Delaying your first coffee has a plausible cortisol-and-adenosine rationale but limited evidence. Worth a try — but the evening cutoff matters more.Thu, 09 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-night-shifts/https://caffiq.app/articles/caffeine-and-night-shifts/Night-shift caffeine advice, rebased: the "stop by 2 p.m." rule doesn't fit when you sleep in the morning. How to time your last coffee to your schedule.Wed, 08 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-coffee-dehydrate-you/https://caffiq.app/articles/does-coffee-dehydrate-you/No — moderate coffee doesn't dehydrate you. The water in it outweighs caffeine's mild diuretic effect, so coffee counts toward your daily fluids.Wed, 08 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/do-coffee-naps-work/https://caffiq.app/articles/do-coffee-naps-work/A coffee nap means drinking a coffee, then napping 20 minutes. Why the timing works, what the research shows, and the catch that can cost you your night.Tue, 07 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/how-long-after-coffee-can-you-sleep/https://caffiq.app/articles/how-long-after-coffee-can-you-sleep/You had a coffee too late — when can you actually sleep? Estimate when caffeine drops to a sleep-friendly level, with a worked mg-by-hour example.Mon, 06 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-after-dinner/https://caffiq.app/articles/coffee-after-dinner/An espresso after dinner is a lovely ritual — and a long caffeine tail. Whether it costs your sleep depends on you, the dose, and the clock.Fri, 03 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-caffeine-affect-deep-sleep/https://caffiq.app/articles/does-caffeine-affect-deep-sleep/Falling asleep fine after a coffee doesn't mean you slept well. How caffeine trims deep sleep — and why your tracker sees what you can't feel.Fri, 03 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/does-decaf-have-caffeine/https://caffiq.app/articles/does-decaf-have-caffeine/Decaf isn't caffeine-free — ~2–5 mg a cup versus ~95 mg for regular. What's really left, how it's removed, and why good decaf changes everything.Thu, 02 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/matcha-vs-coffee-caffeine/https://caffiq.app/articles/matcha-vs-coffee-caffeine/Matcha usually has less caffeine than coffee, plus L-theanine — an amino acid that smooths the lift into calmer focus. Why the two feel different.Wed, 01 Jul 2026 00:00:00 GMThttps://caffiq.app/articles/energy-drinks-vs-coffee/https://caffiq.app/articles/energy-drinks-vs-coffee/Per serving, an energy drink and a coffee have similar caffeine. The real differences: the sugar, the hidden guarana caffeine, and how fast you drink it.Tue, 30 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/espresso-vs-filter-coffee-caffeine/https://caffiq.app/articles/espresso-vs-filter-coffee-caffeine/Espresso tastes stronger, but a single shot usually has less total caffeine than a mug of filter coffee. Why concentration isn't the same as dose.Mon, 29 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/cold-brew-caffeine/https://caffiq.app/articles/cold-brew-caffeine/Cold brew often has more caffeine than hot coffee — ~150–240 mg a serving. Why the long steep wins, and how it differs from iced coffee.Fri, 26 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/smoking-and-caffeine/https://caffiq.app/articles/smoking-and-caffeine/Smoking speeds up caffeine metabolism, so quitting can roughly double the caffeine in your blood — and the jitters get blamed on nicotine.Fri, 26 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-at-night-still-sleep/https://caffiq.app/articles/coffee-at-night-still-sleep/Some sleep fine after an evening espresso — usually fast metabolizers or low responders. Why it happens, and the catch: sleeping isn't sleeping deeply.Thu, 25 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-age/https://caffiq.app/articles/caffeine-and-age/Coffee you slept through at 25 now keeps you up. It's mostly your sleep changing with age, not caffeine lingering longer — and here's how to adjust.Wed, 24 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-tolerance-reset/https://caffiq.app/articles/caffeine-tolerance-reset/If coffee barely registers, that's caffeine tolerance. Why it happens, why the sleep hit stays, and how to reset it without quitting.Tue, 23 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-sensitivity-adora2a/https://caffiq.app/articles/caffeine-sensitivity-adora2a/If half a cup leaves you wired, you may be caffeine-sensitive. The two kinds of sensitivity — clearance and response — and the ADORA2A gene behind it.Mon, 22 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-headache-skipping-coffee/https://caffiq.app/articles/caffeine-headache-skipping-coffee/Skip or delay your usual coffee and a headache creeps in. Why it happens, why it hits on weekends, how long it lasts, and how to avoid the dip.Fri, 19 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/coffee-and-heart-palpitations/https://caffiq.app/articles/coffee-and-heart-palpitations/A fluttering or pounding heartbeat after coffee is common. Why caffeine can be the trigger, when to see a doctor, and how to track your intake.Fri, 19 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/too-much-caffeine-what-to-do/https://caffiq.app/articles/too-much-caffeine-what-to-do/Had too much caffeine today? You can't flush it out fast — but you can stop it getting worse, ride it out, and protect tonight. Plus when to seek help.Thu, 18 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/why-does-coffee-make-you-anxious/https://caffiq.app/articles/why-does-coffee-make-you-anxious/Coffee can leave you jittery, tense, or on edge — caffeine's stimulant effect, not a flaw. Why it happens, and how to keep your coffee without the edge.Wed, 17 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-crash/https://caffiq.app/articles/caffeine-crash/The caffeine crash is the slump that hits after the lift. Why it happens — adenosine rebound, a sugar dip, hidden sleep debt — and how to avoid it.Tue, 16 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-per-body-weight/https://caffiq.app/articles/caffeine-per-body-weight/Caffeine works per kilogram of body weight, so 400 mg isn't universal. Here's how to work out your own reference — and why weight is only part of it.Mon, 15 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-and-sleep/https://caffiq.app/articles/caffeine-and-sleep/How caffeine delays and lightens sleep, why timing matters more than total amount, and what you can do about it.Fri, 12 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/how-to-find-your-caffeine-limit/https://caffiq.app/articles/how-to-find-your-caffeine-limit/You can't look up your caffeine limit — you find it. A simple, no-DNA-test method to discover your own line in milligrams and by time of day.Fri, 12 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-metabolism-genetics/https://caffiq.app/articles/caffeine-metabolism-genetics/Why some people can drink espresso at night and others can't — the science of caffeine metabolism, the CYP1A2 gene, and what it means for you.Thu, 11 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-calculator/https://caffiq.app/articles/caffeine-calculator/What a caffeine calculator actually computes, what it needs to be accurate, and where every one of them stops — including ours.Wed, 10 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/how-long-caffeine-takes-to-work/https://caffiq.app/articles/how-long-caffeine-takes-to-work/Caffeine starts working in ~15–20 minutes and peaks around 30–60. Time your coffee ahead of when you need it — and what changes the speed.Tue, 09 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/caffeine-content-coffee-tea-energy-drinks/https://caffiq.app/articles/caffeine-content-coffee-tea-energy-drinks/A clear, sourced reference for caffeine content per drink — espresso, brewed coffee, tea, energy drinks, and soft drinks, in mg per serving.Mon, 08 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/how-much-caffeine-per-day-is-safe/https://caffiq.app/articles/how-much-caffeine-per-day-is-safe/General daily caffeine reference points, why your personal limit differs, and how to stay under it while still enjoying your coffee.Fri, 05 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/how-long-caffeine-stays-in-your-system/https://caffiq.app/articles/how-long-caffeine-stays-in-your-system/Caffeine has a half-life of around five hours on average — but it ranges from two to ten. Here is what that means, and what makes your number different.Thu, 04 Jun 2026 00:00:00 GMThttps://caffiq.app/articles/when-to-stop-coffee-before-bed/https://caffiq.app/articles/when-to-stop-coffee-before-bed/There's no universal cutoff — it depends on your body. Here's what the science says about timing your last coffee, and how to find your own line.Thu, 04 Jun 2026 00:00:00 GMT