Loading page
Loading page
Loading substance route
Lethal dose begins at approximately 3,000 mg. Average coffee contains 75–150 mg caffeine.
Effects vary widely by individual, dose, and context.
The physical effects of caffeine can be broken down into several components which progressively intensify proportional to dosage.
The cognitive effects of caffeine can be broken down into several components which progressively intensify proportional to dosage. It contains a large number of typical stimulant cognitive effects. Although negative side effects are usually mild at low to moderate dosages, they become increasingly likely to manifest themselves with higher amounts or extended usage. This particularly holds true during the offset of the experience.
There is considerable risk of physical harm when taking these combinations, they should be avoided where possible.
These combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Caffeine is habit-forming and commonly used daily by millions, though compulsive consumption under any circumstances has not been scientifically observed. Some diagnostic manuals classify caffeine addiction, and some users report difficulty reducing intake despite awareness of negative effects.
A mild form of physical dependence develops with regular daily use above 100 mg. Withdrawal symptoms include headache, fatigue, irritability, depressed mood, difficulty concentrating, and flu-like symptoms, typically beginning within 24 hours of cessation and generally resolving within one day.
The estimated lethal dose in humans is 150-200 mg/kg of body weight, equivalent to approximately 10.5-14 grams for a typical 70 kg adult or roughly 75-100 cups of coffee. Deaths have occurred at doses as low as 57 mg/kg in some cases. Fatalities are rare and most commonly caused by intentional overdose of caffeine powders or supplements, where a tablespoon-sized amount can be lethal. The lethal dose is lower in individuals with impaired caffeine metabolism due to genetics or chronic liver disease.
| Species | Route | Value |
|---|---|---|
| rat | oral | 192 mg/kg |
High caffeine intake, particularly from energy drinks exceeding 320 mg, is associated with short-term cardiovascular effects including elevated blood pressure, prolonged QT interval, tachycardia, and heart palpitations; these effects are typically acute and dose-dependent, with tolerance developing to autonomic cardiovascular effects with chronic use.
Caffeine stimulates gastric acid secretion and increases gastrointestinal motility; long-term high-dose consumption of coffee may contribute to stomach ulcer formation.
In postmenopausal women, high caffeine consumption has been associated with accelerated bone loss.
Rhabdomyolysis has been reported in cases of very high caffeine intake exceeding 5 grams, a dose approaching lethal levels.
Psychotic symptoms including delusions, hallucinations, mania, disorientation, and disinhibition may occur only at very high doses exceeding 5 grams, approaching lethal levels. At typical consumption, caffeine may induce or worsen anxiety rather than psychosis; caffeine-induced anxiety disorder is recognized in the DSM-5.
Seizures may occur in cases of caffeine overdose due to central nervous system overstimulation. Individuals with epilepsy or other seizure disorders should use caffeine with extreme caution.
Caffeine-containing plants have been utilized by human cultures across multiple continents for millennia, with various civilizations independently discovering the stimulating properties of different botanical sources.…
Classified by the FDA as 'generally recognized as safe' (GRAS). Beverages containing less than 0.02% caffeine are considered safe under FDA guidelines. Caffeine powder sold as a dietary supplement remains unregulated. Food labeling requires caffeine to appear in ingredient lists when added, but there is no mandatory quantitative labeling requirement for caffeine content. Natural caffeine sources such as guarana or yerba maté are not required to identify caffeine presence or quantity. FDA guidance was updated in 2018.
11 sources cited
