The amount of caffeine considered dangerous varies depending on the individual, but general guidelines exist:
- For most healthy adults, consuming up to 400 milligrams (mg) of caffeine per day is considered safe and not generally associated with negative effects. This is roughly equivalent to four cups of brewed coffee
- Toxic effects, including seizures, can occur with rapid consumption of about 1,200 mg of caffeine or more, which is less than half a teaspoon of pure caffeine powder. Such high doses can be life-threatening
- Extremely high doses, in the range of several grams (e.g., 10 grams), can cause fatal caffeine overdose, but reaching this level through common beverages is very difficult
- Sensitivity to caffeine varies widely among individuals, influenced by genetics, medications, medical conditions, pregnancy, and breastfeeding. For example, pregnant or breastfeeding women are advised to limit caffeine to less than 200 mg daily
- Children and adolescents should consume much less caffeine; for instance, healthy teens are advised to keep intake under 100 mg daily, and caffeine is generally discouraged for children under 12
- High caffeine intake can cause side effects such as anxiety, nervousness, increased heart rate, insomnia, and in extreme cases, irregular heartbeat and death
In summary, while 400 mg per day is a widely accepted safe limit for most adults, consuming around 1,200 mg or more rapidly can be dangerous and potentially toxic. Individual tolerance varies, so symptoms like jitteriness or palpitations indicate that intake should be reduced
