TL;DR The ideal amount of caffeine intake in a day boils down to 400 mg, which is equivalent to many different things depending on the food or drink you're taking. When you consume more than this amount, some adverse effects may take place like headache, anxiety, and insomnia.
Coffee, tea or (caffeine) mints.
So, which of these have you popped or downed today?
These products all contain varying amounts of caffeine, alongside others you wouldn't have thought to contain it. Ice cream, frozen yogurt, breakfast cereals, pudding, pain medications … even cocoa butter lotion apparently all have it! 
Do you like most (or all) of these products? Then you must be wondering how much caffeine you take in daily.
We've got you covered.
Keep reading to find out the safe amount to consume and what might happen if you get too caffeine-happy.
Let's start with a very important question:
How much is too much?
Studies have shown that caffeine remains in the safe zone when consumed in low-to-moderate amounts . But what exactly does “low-to-moderate” mean?
The most important figure to remember on this topic is...
400 milligrams (mg).
That’s the amount of caffeine that’s considered safe to consume in a day… at least for adults. 
If you’re wondering what 400 mg means, you can refer to image below:
Note that caffeine content varies in different products so don’t forget to check the label!
And if you’re wondering how much the “killer” amount is (literally), then USA Today reports it would “likely take anywhere from 50-100 cups of coffee,” or a teaspoon of pure powdered caffeine ingested at once. 
Now you must really love your caffeine to death if you take in that much!
Drinking too much coffee or tea can cause withdrawal symptoms, caffeine rebound and medication rebound, which can all lead to migraine or the worse version of your typical headache. How this happens is covered in our article “Does caffeine cure or cause migraines?”
From modest doses [7, 8] to incredibly high intake (1,000 mg or more) a day [9, 10] caffeine could cause nervousness, rapid breathing, stress and mood swings. And studies say these adverse effects can take place regardless of how many times you have your caffeine – whether you’re a coffee-lover or just an occasional drinker. 
Read this article to find out when’s the best time to drink coffee.
Muscle tremors or rhabdomyolysis
Excessive caffeine intake can also cause rhabdomyolysis, which is a “serious syndrome due to a direct or indirect muscle injury. It results from the death of muscle fibers and release of their contents into the bloodstream.” [14, 15, 16, 17, 18]
One study cited a woman who guzzled a liter of coffee with 565 mg worth of caffeine and eventually suffered from symptoms of rhabdomyolysis, i.e. nausea, vomiting and dark urine. Don’t worry, she recovered after getting medical attention. 
High blood pressure
Rapid heart rate
Stimulant overload can also alter the rhythm of your heartbeat, which was reported among young people who had gone overboard with their energy drinks. 
More trips to the toilet
Most research reports higher likelihood of frequent urination or inability to control urination with excessively high caffeine intake, especially among older people or those suffering from incontinence.
In some cases, high consumption may even likely develop incontinence among those with a healthy bladder. 
While caffeine may be safe for adults, its effects could vary based on people’s tolerance. Research shows that genes may have something to do with it. That’s why some can have more cups of coffee over others without having any drawbacks. [28, 29]
Some people though should carefully watch their intake, especially the following:
The key to consuming caffeine without feeling robbed of your daily fix is to pay attention to your body and whether you're seeing signs of any of the adverse effects above.
If you think you're heading towards the danger zone, try to ease off on your favorite caffeine products and mix them up with decaffeinated ones.
But the most important one is to know is the content of the products you consume. Check the label, but be vigilant at the same time (some products may be disclosing a lower amount than the real one).
If you're not sure how much caffeine a product is supposed to have, fret not. Here's an infographic to guide you the next time you have your caffeine.
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Is there a big difference between synthetic and natural caffeine? Which gives a stronger jolt? Does it even matter?
Natural caffeine in coffee, tea, and chocolate is much less common than the synthetic caffeine found in so many other products.
Caffeine is found in plant species such as the more popular ones like Coffea arabica and Coffea robusta, as well as tea leaves, kola nuts, cacao beans, Yerba mate and guarana berries.
Not only does naturally-occurring caffeine from said plants keep your cognitive functions at their peak, but it also contains antioxidants that help you fight illnesses like cancer and Alzheimer’s.