Sleep

The real 8–10 hour cutoff — Drake 2013, CYP1A2 genetics, and the "decaf is not zero" trap.

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Anxiety

DSM-5 caffeine-induced anxiety disorder — thresholds, tapering, and panic-disorder caution.

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Heart Palpitations

Caldeira 2013 and Chieng 2022 meta-analyses — plus emergency red-flag symptoms.

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ADHD

What the evidence actually shows — not a substitute for treatment.

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Medications

Full interaction table — fluvoxamine, ciprofloxacin, contraceptives, lithium, stimulants, and more.

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Caffeine Withdrawal

Symptoms, hour-by-hour timeline, and the evidence-backed strategies that shorten the worst of it.

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How to Cut Back

A 21-day taper plan that minimizes headaches, brain fog and rebound fatigue.

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Caffeine Reset

Restore caffeine sensitivity in 14-21 days — without going to zero.

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Mindful Caffeine

Eight habits that separate intentional users from compulsive drinkers.

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Caffeine Tracker App

What a real caffeine tracker should do — half-life, cutoff alerts, source database.

See the buyer's guide