Introduction:Do you think milk tea contains no caffeine? In fact, it also contains caffeine that can boost alertness, though the amount is usually lower than in coffee. This article delves into the sources of caffeine, the differences in its content across various beverages, and explains in detail how caffeine is metabolized in the human body, its half-life duration, as well as the factors that influence its metabolism rate. This will help you plan your consumption time more wisely and avoid affecting your nighttime sleep.

When you invite a friend to have a cup of coffee together in the afternoon to relax, you often hear them say, “I’m afraid I won’t be able to sleep at night,” and then opt for milk tea instead — a conversation scenario many are familiar with. But did you know? Milk tea actually contains caffeine too, just at a generally lower concentration, leading many to mistakenly believe it’s a “guilt-free” choice.

Caffeine is a natural central nervous system stimulant, widely found in various plants, including the familiar coffee beans and tea leaves. In fact, over sixty types of plants, such as kola nuts and cacao beans, also contain this compound. Beyond natural sources, there is also a significant amount of synthetic caffeine, commonly found in medications, energy drinks, and even certain chewing gums, used to help enhance alertness or relieve fatigue.

So, how much does the caffeine content vary across different beverages? According to publicly available data, a cup of coffee weighing about 225 grams typically contains between 95 and 200 milligrams of caffeine; a can of cola weighing around 340 grams contains approximately 35 to 45 milligrams; an energy drink of about 225 grams usually has 70 to 100 milligrams of caffeine; and a cup of tea weighing around 225 grams contains roughly 14 to 60 milligrams of caffeine. From this, it’s clear that although milk tea generally has less caffeine than coffee, its content should not be underestimated.

After caffeine enters the human body, it is quickly absorbed by the small intestine. Around 10 minutes after consumption, you can begin to feel its stimulating effects. However, it generally takes about 45 minutes to 1 hour to reach peak blood concentration levels. If consumed in tablet form, it may take even longer. For most people, the blood caffeine concentration typically peaks within 1 to 2 hours after intake.

The metabolism speed of caffeine varies from person to person, but on average, its half-life is about 3 to 7 hours. This means that if you consume a caffeinated beverage at 3 PM, by 9 PM, there may still be about half of the caffeine left in your body that hasn’t been metabolized yet. This is one of the reasons why some people find it difficult to fall asleep at night after drinking tea or coffee in the afternoon.

So, how long does it actually take for caffeine to be completely eliminated from the body? There is no absolute standard, as the metabolism time is influenced by various personal factors, such as age, weight, gender, whether one is pregnant, the condition of kidney and liver functions, as well as individual sensitivity to caffeine. Generally speaking, younger individuals with better physical fitness tend to metabolize caffeine faster than older individuals or those with weaker metabolic functions.

In the human body, caffeine is primarily metabolized by the liver’s cytochrome P450 oxidase system and broken down into three main metabolites: paraxanthine (about 84%), theobromine (about 12%), and theophylline (about 4%). These metabolites are further broken down and eventually excreted through urine. For this reason, individuals with impaired liver or kidney function may experience a longer retention time of caffeine in the body and need to pay extra attention to their intake.

In summary, if you wish to enjoy good sleep quality at night, it is recommended to avoid consuming caffeinated beverages in the latter part of the afternoon, especially for those who are more sensitive to caffeine. Additionally, since milk tea also contains caffeine, if you have high standards for sleep quality, you might want to pay closer attention to the ingredients when choosing beverages, or opt directly for caffeine-free alternatives, in order to truly achieve relaxation and rest.

The above content is compiled by CoffeeHunters, a coffee news website.