Caffeine: Everything You Need To Know In 2022

Did you know that light roast coffee beans contain more caffeine than dark roasted ones? Did you know that caffeine amplifies stress response in your body? Have you ever thought about calculation of your safe daily dose of caffeine? And what about Starbucks coffee with its highest caffeine amounts among all famous coffee-shop chains? If you answered “No” to all these questions – this caffeine guide is definitely a MUST read for you! We’ve collected the most essential information here and, of course, you won’t be bored!

Let’s cut down to the essentials.

What is caffeine? Which dose is safe?

Caffeine is a natural stimulator which derives from seeds and leaves of more than 60 plants, including coffee beans, tea leaves and buds, cocoa beans, kola nuts, guarana seeds etc. Also, it’s one of the most widely used drugs on Earth. Thousands… no, actually, millions of people consume it every day to wake up, enhance concentration, combat fatigue and just activate the nervous system, heart and muscles. Generally, caffeine activates our brain’s electro biological activity, increases positive conditioned responses, improves physical and mental performance.

We’re talking not only about coffee here, people can also get it from different sources – starting from chocolate and tea, ending with synthetically produced caffeine in prescription and non-prescription drugs. Also, we’re sure that you’ve heard about energy-boosting gums or caffeine patches – they become highly popular nowadays!

Don’t worry, we’re not going to burden you with so boring medical prescriptions of caffeine usage and its dosage (we’re not doctors, yet:)). But it is worth mentioning that according to FDA, the European Food Safety Authority, and Health Canada, caffeine consumption of up to 400 mg daily is not associated with adverse effects on the human body in healthy adults, except pregnant women.

Well, let’s make it clear what makes 400 mg of caffeine! This is equal to:

• 2 bottles of “energy shot” drinks
• 5.2 espresso shots
• 5 cans (8 fl oz) of Red Bull
• 1 cup of Starbucks Venti brewed coffee
• 2.5 cans (16 fl oz) of Monster Energy Drink
• 11.7 cans (12 fl oz) of Coca-Cola classic

Doctors recommend pregnant women not to exceed the limit of 200 mg of caffeine per day, teenagers shouldn’t consume more than 100 mg, and for children, it’s better to avoid it at all. One cup of coffee usually contains 100–200 mg of caffeine, tea – about 70 mg, carbonated drink – not more than 50 mg.

Caffeine is a fast-acting substance and can easily penetrate into our bloodstream through mouth and stomach: 99% will be absorbed within a maximum 45 minutes since the moment you’ve consumed it. Its average half-life is 4 to 6 hours – that’s why you can feel its effect during this time. Half-life may be different depending on your age, health conditions and your sensitivity.

Caffeine in certain doses stimulates alertness in the cerebral cortex. Small doses help fight drowsiness, relieve fatigue, invigorate, increase physical and mental activity. High doses can lead to depletion of nerve cells. And, as already mentioned, each person has an individual reaction to it.

We bet you’ve heard a lot of things (both good and bad) about caffeine and its effects on our body. Moreover, many scientists and doctors have a lot of disputes around it. So, let’s just try to verify them here.

Caffeine positive effects on human body

First of all, regular coffee consumption increases our longevity and reduces the risk of premature death by 20-30%.

Also, caffeine blocks adenosine receptors in the brain, which are responsible for drowsiness and alertness suppression. Due to the similar structure of molecules, caffeine can easily bind to adenosine receptors and not allows adenosine to bind to our brain cells and give a signal to take a rest or sleep. Since the adenosine cannot produce drowsiness symptoms, caffeine stimulates intellectual and physical activity.

Interesting fact: when caffeine blocks adenosine, dopamine system in our brain works more effectively. It means that a number of our functions are enhanced, namely: memory, mood, attention, vigilance etc.

Some researches say that caffeine consumption can prevent cognitive decline and dementia, but this question requires more deep study.

At the same time, several studies showed that coffee can also benefit your mental health. Women who drink it on aregular basis are less depressed and have a lower risk of suicide.

Also, scientists from Johns Hopkins University have found that caffeine is a good memory enhancer. They conducted a study and figured out that it has a positive effect on our long-term memory, and showed that some memories can be enhanced up to 24 hours after it’s consumed.

Another study, made by Alberto Ascherio (professor of nutrition and epidemiology), showed that daily intake of 4-5 cups of coffee decreases the risk of Parkinson’s disease about in half comparing to low or no intake of caffeine.

Besides, our today’s hero can boost your metabolism and help in losing weight! According to scientific research metabolic rate increases significantly within 3 hours after ingestion of 8 mg/kg of caffeine in normal weight and obese people. Scientists mentioned that greater fat oxidation (normally speaking this is energy burn) was observed in participants with normal weight. Accordingly, calories burn causes weight reduction! Of course, it’s not the case with coffee drinks with crazy calorie amounts!

Caffeine in coffee can make you more energized and improve your physical performance by up to 12%.

Can you believe that 2 cups of coffee can protect the liver? We do! Surveys show that coffee has a protective effect on liver diseases (HCC, HBV) with risk reduction by 30-80%. One more study confirms that moderate coffee consumption can help to lower the risk of liver cirrhosis.

People drinking coffee have 23–50% lower risk of developing type 2 diabetes. Each daily cup of coffee is associated with a lower risk up to 7%.

There are also a lot of researches which shows evidence that coffee & caffeine consumption is associated with a lower risk of cancer, stroke, Alzheimer’s disease, erectile dysfunction, etc. However, you should keep in mind that most of these studies are just observations. Actually, they haven’t proved in real-life experiments yet that coffee or caffeine reduces the risk of the disease.

Caffeine negative effects on human body

As usual, there is another side of the coin. Consumption of too much (more than 400-600 mg/day) caffeine can lead to different adverse effects such as insomnia, headache, anxiety, heart palpitations and so on.

The most well-known fact about caffeine is that it can disturb sleep. Its consumers can have problems with falling asleep, they may have brief awakes during the night, which reduces the restorative effect of their sleep. As a result, it’ll affect the next day’s mood and condition – a person can be fatigue and have anxiety. So, better not to consume caffeine 4-6 hours before your bedtime.

Drinking coffee on an empty stomach can really be dangerous for your health. Consumption of caffeine, regardless of the amount increases the production of hydrochloric acid (HCI) in your intestinal tract. Under normal conditions, the body produces HCI in optimal amounts for digestion. When the production of HCI reaches its limit, occurs a shortage for digesting large amounts of food. It causes a stomach upset and heartburn (sometimes). Also, laxative effect of caffeine can be caused by the gastrin release – this is a hormone that is produced by stomach and increases activity in the large intestine.

One more fact is that caffeine affects our bodies like a drug, causing similar reactions in the central nervous system as drugs use, which ultimately can lead to caffeine dependence. Thus, some people may become physically dependent on the use of caffeine and if they refuse to use it, they may experience headaches, lethargy, depression, and nausea.

Additionally, by enhancing the production of catecholamines (epinephrine and norepinephrine), caffeine causes stress in our body. This is one of the factors contributing to an increase in blood pressure, which is often found in coffee lovers. And high blood pressure is one of the main risk factors for heart attack.

Caffeine consumption can also cause a deficiency in group B vitamins, specifically B1 (thiamine), which provides and regulates carbohydrate metabolism (including metabolism in the skin) and nerves in our body. Lack of it deteriorates the quality of the skin, hair, and memory.

Love for coffee can prevent a woman from getting pregnant, according to scientists from the University of Radboud (The Netherlands). The researchers came to this conclusion after a large study with the participation of 9,000 women. Having studied the factors that could contribute to or discourage conceive, scientists concluded that daily consumption of 4 cups of coffee, strong tea or other caffeine-containing beverages reduces the likelihood of conception by 26%.

All those facts don’t really mean that you have to quit the consumption of caffeinated products, just pay your attention to how much caffeine you consume every day.

What factors affect caffeine content in coffee

In general, the caffeine content in coffee is extremely variable and constantly changing. In energy drinks or food supplements, сaffeine is added to each batch and its exact amount is indicated on the product’s label. But coffee drinks sometimes can have a rather large range of caffeine content. It may vary depending on different factors. So, let’s figure out which exactly!

Coffee beans type. Although the arabica’s taste characteristics are higher valued comparing to robusta’s, nevertheless, caffeine content in the latter beans is relatively lower. For example, 170 ml of coffee, made from robusta beans, contains around 200 mg of caffeine, the same cup, made of arabica beans, has about 110 mg of caffeine. Moreover, beans of different origins (and even harvest) naturally contain different amounts of caffeine.

Roasting. It is commonly believed that the darker the roast, the more caffeine it has (due to the rich taste and aroma coffee seems to be more strong). But this is not the case. Prolonged high-temperature exposure has a destructive effect on the substance’s molecules.

Grind. Each method of coffee making requires a particular grind. For example, for a drip coffee maker or french-press, the fine grind is not necessary, meanwhile Turkish coffee requires to turn coffee beans almost to the dust. It worth considering that the finer the grind, the more caffeine the drink contains, as it’s much easier to wash out (with the help of hot/cold water) caffeine from small particles.

Brewing method and duration. The opinion that a large amount of water reduces the amount of caffeine in a cup of coffee is incorrect. With the same amount of coffee you can make a drink of different strength. The longer the brewing process takes, the higher the caffeine concentration will be. So, coffee from the french-press, which has been infused for a long time, has a higher caffeine content comparing to instantly prepared ristretto, for example.

Despite all these variables – cold coffee has less caffeine in its composition than a cup of a hot one. During brewing process hot water extracts and dissolves caffeine, hence, the hotter the water, the more it will pull it out of coffee. Cold water, which is used in cold brew, cannot extract so much caffeine. So, hot coffee contains more caffeine than the modern cold one.

But, a cold coffee infusion is usually made with a higher ratio of coffee to water (2 to 2.5 times). This means that it is stronger compared to the regular brewing. However, cold brew is high concentrated and must be diluted with water or milk in 1:1 ratio, which reduces the level of caffeine again.

How much caffeine is in one cup of coffee?

And yet, which coffee has more caffeine, and which drink is the best one to stay awake? Well, now we go from words to figures.

This table shows typical caffeine contents in coffee drinks:

Source: Mayo Clinic

Considering above mentioned information, it’s better to consume not more than 2-3 cups of coffee per day. Also you should consider that some other products, which you can eat/drink during the day can have caffeine in their content too, so be cautious about it.

Now you know how much caffeine is in a cup of coffee, so you can easily choose a drink of suitable strength. In order to give every sip a real pleasure, give preference to quality coffee of reputable brands.

BTW, about brands… We decided to make a database of coffee drinks with caffeine for you, so that before making your choice you can estimate your intake.

Starbucks

As you may know, Starbucks has its own system of drink sizes and it totally differs from other coffee shops. So, while buying coffee there, you need to choose your drink volume among the following sizes: Short (8 fl oz.), Mini (10 fl oz.), Tall (12 fl oz.), Grande (16 fl oz.), Venti (20 fl oz.), Venti Iced (24 fl oz.) Trenta Iced (31 fl oz.). But pay attention that some sizes are not available for some drinks.

Both drink sizes and caffeine content we listed in the following table.

Source: Starbucks

Some highlights for you:

• The lowest caffeine content is in Decaf Pike Place® Roast
• The highest caffeine content is in Blonde Roast, Clover® Brewed Coffee and Pike Place® Roast. The biggest sizes contain more than 400 mg, so be careful not to overdose.
• Lots of Starbucks’ espresso beverages are prepared with single (Short and Tall sizes) or double shot (Grande and Venti sizes) of espresso with 75 mg and 150 mg of caffeine respectively.
• Some of the Creme Frappuccinos are caffeine-free.

Dunkin’ Donuts

60 cups of freshly brewed coffee per second – that’s how many cups of joy are selling in Dunkin’ Donuts chain worldwide on an average day. Can you imagine that?!

DD is serving 4 sizes of drinks: S, M, L and XL. This brand offers a wide range of caffeinated drinks in 4 sizes (S, M, L and XL) and here is the table with caffeine contents of each:

Source: Dunkin’ Donuts

• The highest caffeine content in a medium cup is in Iced Coffee – 297 mg / 14 oz.
• Lowest – is in Vanilla Chai –  80 mg / 14 oz.

McDonald’s (McCafe)

There is no such person, who has never drunk coffee from McDonald’s! This worldwide chain sells coffee drinks under the McCafe brand. Unfortunately, they don’t give exact caffeine content per each drink and size, but we’ve found some information about the most popular drinks:

Source: Caffeineinformer

Caffeine in tea vs coffee

Contrary to popular belief, tea contains even more caffeine than coffee. When a portion of espresso made from 100% Arabica beans has up to 1.2% caffeine, the caffeine content of a high-quality Assam teacup, for example, can reach as much as 4%. But, caffeine, which is contained in dry leaf tea, cannot be fully extracted, it means that its actual content in the cup of tea will always be somewhat lower.

Here is the table of common caffeine content in teas:

Source: Mayo Clinic

Basically, tea caffeine affects the heart and nervous system more gently comparing to coffee, and its effect won’t be so pronounced, but a bit longer. This is due to the fact that in tea this alkaloid is not presented in its pure form, but in combination with tannin. Combo of caffeine and tannin creates a new substance (theine), which is rather slowly absorbed into the blood and can be quickly withdrawn from the body. Therefore, it is impossible to poison yourself with theine even if you drink strong tea in very large quantities (up to 12 cups per day).

It’s worth mentioning, that natural stimulant content in tea entirely depends on region, where tea tree was growing, variety of tea, plant’s age and age of a leaf, soil quality and even weather conditions.

Another important factor affecting caffeine content is the degree of tea leaf fermentation. The lower it is, the more caffeine is in the tea. Hence, the most “caffeinated” varieties are white teas, green teas and oolongs. But in fact, there is more to it than that. What matters is not only the variety, but also the method of making tea, including the temperature of the water for brewing. The hotter the water, the more actively the caffeine is released. And since unfermented and weakly fermented teas are brewed with warm rather than hot water, they contain less caffeine, than saturated black tea.

Caffeine contents in different products

Well, as mentioned above, caffeine is contained not only in coffee and tea. There are so many products with it! Actually, the market for caffeinated beverages has been increasing during the last 20 years. Currently, it’s introduced with different kinds of energy drinks, sport drinks, juices and even waters. Moreover, caffeine can be found in caffeine in cocoa, hence, chocolate, drugs, and dietary supplements.

Surveys show that nowadays almost 80% of the world consumes caffeinated products on a daily basis and up to 90% of North America’s adults consume caffeine every day. Mainly natural stimulant is consumed with beverages, namely, coffee (71%), soft drinks (16%), and tea (12%).

We’ve decided to present here a list of products with the highest caffeine content in each category.

Soda (for your convenience we’ve calculated caffeine contents in the same q’ty of the drinks):

Source: Caffeineinformer

Energy products:

Source: Caffeineinformer

Some of the drinks are incredibly energetic, so be careful while drinking them!

Caffeine myths

Caffeine addiction: truth or not?

Probably it’s the most widespread question! In reality, there is no clear answer to it. Studies show that you really can get used to caffeine. However, this, so to say, “dependence” is not an “addiction”.

Caffeine cannot threaten your emotional, physical and social health in the same way as do drugs, even the lightest and legal ones like cigarettes or alcohol.

If you decide to refuse coffee & caffeinated products, most likely, your body will not even feel it. Only in some cases (for example, if you are accustomed to using 2 or more cups a day) you may experience unpleasant symptoms such as drowsiness, anxiety, irritability, fatigue or even headaches.

But all these effects of withdrawal won’t be too pronounced and are unlikely to last longer than 1 or 2 days. For this reason, experts do not consider your love to caffeine as a serious addiction, which would require professional treatment to overcome it.

Caffeine removes calcium from the body

Due to it, caffeine is considered a reason for osteoporosis development. But in reality, it’s still an open question.

Indeed, if you consume a lot of caffeine (more than 744 mg per day, which is equivalent to about 12 standard espresso cups), it can worsen the calcium absorption in the intestine. However, studies show that it’s enough to add 1–2 tbsp. of milk to your coffee, and the negative effects of caffeine will be compensated.

However, older people need to be more careful with coffee: there is still some connection between the effect of caffeine and the risk of hip neck fracture. Scientists have an assumption that in older people caffeine has more powerful effect on calcium metabolism. So, if you are over 50, try to reduce caffeine consumption to 300 ml per day.

Caffeine has a diuretic effect

Scientists have proven that very large doses of caffeine can actually affect kidneys, causing a diuretic effect. But they were talking about such significant amounts of this alkaloid, which is not possible to consume per day for an average coffee lover.

Actually, caffeine does have a slight diuretic effect, but it does not lead to additional loss of fluid in excess of that which was ingested along with the drink itself. There is only one exception: if you drink 2-3 cups of strong coffee in a row, the diuretic effect may become more pronounced. However, it is observed only with those people who did not drink coffee before.

So, if you strive to maintain an optimal fluid balance in your body, you should not worry about the consumption of caffeinated beverages. They can even contribute to your hydration.

Caffeine helps to sober up

This myth is not just useless, but also very dangerous! A lot of articles about “How to sober up quickly” recommend to drink coffee as one of the options. Yes, coffee really helps to mask booze breath. But in terms of real sobering, the drink is even harmful due to possible disastrous outcomes. As a stimulant, caffeine invigorates and energizes. Due to this, a drunk person gets the false feeling that he has come to himself and has become almost sober!

In 2009 the American Psychological Association published a report, which was based on the test results of 2 groups of people. The first group was under the influence of alcohol. The second – the same, but participants consumed coffee after alcohol intake. According to the survey, the representatives of the 2nd group unanimously reported that they felt sober. However, tests results for attentiveness, concentration and coordination were not better than the drunk volunteers’ results from the 1st group.

At best, caffeine will not affect the alcohol withdrawal, and at worst – it will intensify the harm of intoxication, since the body will have to split two types of active substances at once, and, at the same time, the nervous system will respond to both types of stimuli.

Caffeine causes cancer

This is definitely a myth. Lots of studies haven’t found any associations between caffeine intake and the development of any type of cancer. On the contrary, due to the antioxidants found in coffee, tea and cocoa, their consumption reduces the risk of certain types of cancer, especially of all parts of the digestive system. For example, the risk of colon cancer in people who regularly consume caffeine in various forms is reduced by 40%. The risk of oral cancer and even some types of brain, liver and breast cancers was reduced by almost the same amount.

The Bottom Line

In case of proper use and in moderate doses, caffeine is a useful product that allows us to feel alert and improve our mental and physical performance without any harm to our health. Regular consumption of moderate doses of this alkaloid also has a positive effect on our health – improves metabolism, increases muscle strength, eliminates fatigue etc. But everybody knows that we can easily go overboard with it and get some adverse effects, which we’ve described above.

Scientists agree that 400 mg of caffeine per day is the maximum safe dose for an adult. This is about five cups of espresso or one venti size coffee from Starbucks (400 ml) per day. Of course, it is better not to reach this figure at all, even if it’s the best coffee in the world, because a safe dosage of caffeine is different for each person, and it can be much less than the specified maximum. Moreover, there are a lot of people with different sensitivity to it.

We sincerely hope that our article will help you to control your daily intake of caffeine and enjoy your favorite drinks without remorse and stay healthy and energized!

Well, the story was loooong, but we hope you’ve enjoyed the ride! Thank for being with us! Stay tuned!