Nutrition Myths
Is caffeine bad for you?


  • The positive or negative health effects of caffeine mainly depend on the individual’s genetic predisposition.
  • Caffeine is generally more beneficial for fast caffeine metabolizers which represent the majority of the population.
  • For this group, 400-500mg of caffeine daily provides the maximum health benefits and the minimum negative side-effects.
  • Caffeine generally improves brain function (such as alertness, learning capacity and mood) and is beneficial in mental health (depression, dementia, Alzheimer’s and Parkinson’s disease)
  • Caffeine exerts small weight reducing effects, but only in the short term.
  • Long term caffeine consumption may decrease the risk of gout.
  • Fast caffeine metabolizers may improve their heart health by drinking 4 caffeinated coffees per day.
  • The risk of malignant melanoma may be reduced by drinking caffeinated coffee. Evidence is still weak.
  • Caffeine may be beneficial in reducing the risk of type 2 diabetes.
  • Caffeine together with other coffee constituents may be protective against liver cirrhosis.


Health benefits of caffeine – is it really good for you?

There is no definitive answer to the question of whether caffeine is beneficial or detrimental to health. Everyone reacts to caffeine differently and health benefits of caffeine as well as its harmful effects should be considered on individual bases. This article lists most commonly claimed caffeine benefits and discusses available evidence.

Related articles:

  • Side effects of caffeine – health consequences of regular caffeine intake.
  • What amount of caffeine can cause an overdose? Symptoms of caffeine overdose.
  • What is caffeine sensitivity and why it is the main factor that explains how we react to caffeine?
  • Caffeine allergy.
  • What are the caffeine withdrawal symptoms and how to build tolerance to caffeine.
  • What are the caffeine contents in caffeinated beverages?

What is caffeine? Is caffeine a drug?

Caffeine is a naturally occurring substance in fruits and the leaves of plants such as coffee, tea, yerba mate and guarana. It is present in many products including sodas, energy drinks, chocolate, cough syrups and slimming tablets.

Caffeine is also added to some over-the-counter medicines such as cold medications. Caffeine contents in drinks and foods may range anywhere from trace amounts in decaffeinated drinks such as coffee or tea to over 300mg per serving in products such as energy drinks or Starbucks coffee.

For the full list of contents of caffeine in drinks please see “Caffeine levels in drinks and foods”

Caffeine is a stimulant drug (known as a psychoactive drug) that affects the nervous system, causing symptoms such as alertness and temporary mood elevation.

It also affects the rest of the body such as the hormonal system and the metabolism of fat during exercise (although studies showing long term weight-loss effects are inconclusive). (1)

Caffeine is a dose-dependent drug. The larger the dose, the stronger the stimulation effects. However, it doesn’t collect in the body, but gets broken down in the liver and excreted through urine. (2)

Caffeine reaches the bloodstream in about 15 minutes, attaining its peak saturation in the blood in 15-45 minutes. It has a half-life of around 6 hours (the time taken for the caffeine concentration in your blood to reduce by half). (3)

Although a drug, caffeine is not addictive like other drugs. Nevertheless, individuals who drink caffeine daily develop a physical dependence to it.

How does caffeine affect your body if you are allergic, sensitive or caffeine-naive?

The way you handle caffeine and the intensity of the symptoms depend on a variety of factors, such as the individual’s sensitivity and tolerance level to caffeine, and in rare cases caffeine allergy.

In other words, the positive and/or negative effects that caffeine exerts on each person and if one should drink caffeinated drinks and in what quantities are closely correlated to:

  • Caffeine allergy

    Caffeine allergy is extremely rare, with only a handful of cases recorded. However, if you show common allergic reactions to caffeine such as hives or anaphylaxis, you should avoid any amount of caffeine.

  • Caffeine sensitivity

    The bottom line is, are you a fast or a slow caffeine metabolizer?

    Caffeine sensitivity is an important factor that determines whether coffee is good or bad for you. The genetic make-up dictates how many caffeine-breaking enzymes are produced by the body, therefore influencing how well you can handle caffeine.

    Being caffeine-sensitive or a slow caffeine metabolizer restricts how much coffee you can manage, by producing unpleasant overdose symptoms as soon as you surpass your caffeine limit.

    Negative rather than positive health effects are likely to occur as a result of caffeine intake. The more caffeine sensitive you are, the less caffeine you are able to consume before you experience the negative effects. In extreme cases, if you are very sensitive, you may not be capable of having any caffeinated drinks.

    Fast caffeine metabolizers, on the other hand, can quickly break down and excrete caffeine. They normally experience a wide range of health benefits of caffeine intake, as mentioned in the section below.

    The main point is that, if you are sensitive to caffeine, drinking caffeinated beverages will bring you more negative than positive effects, depending on the sensitivity level and on the amount consumed. However, if you are a fast metabolizer, the positive impact of caffeine intake described below may be applicable.

    NOTE: many studies on caffeine don’t take into consideration genetic factors.

    You are not sensitive to caffeine. In this case, you may build your tolerance to the point of over-consumption and high dependency (caffeinism), which has detrimental results on your health. Studies don’t show any health benefits from such high amounts of caffeine.

    NOTE: many studies don’t take into consideration the tolerance factor, making the results misleading. For instance, we cannot conclude that energy drinks’ containing caffeine, have a diuretic effect if we don’t know if the participants are usual consumers of caffeinated drinks. Their increased urination may be due to the fact that they haven’t developed a tolerance to caffeine rather than caffeine having a diuretic effect.

Health benefits of caffeine – when is caffeine good for you?

Most of the caffeine health benefits are experienced by people who are not allergic or sensitive to caffeine and don’t consume excessive amounts or overdose on caffeine.

Caffeine benefits in cognitive function and psycho-motor performance

Caffeinated beverages, such as coffee or tea, if consumed throughout the day, improve alertness, learning capacity, mood, memory and psychomotor performance. These results refer to medium to high caffeine users, rather to low caffeine users.

Please note that low caffeine users may be sensitive to it and, therefore, be affected negatively by caffeine intake through anxiety, jitteriness and reduced quality of sleep. (4, 5)

Caffeine benefits in weight loss

Caffeine exerts some weight reducing effects in the short term, by increasing the rate of burning fat and boosting the metabolic rate.

However, in the long term, these effects are negligible due to the increased tolerance to caffeine. Nevertheless, it may be positive as a tablet or powder when taken before exercise to help increase the burning of the fatty tissue. (read more..)

Caffeine benefits in Gout

Long term caffeine consumption is associated with decreased risk of gout. (6)

Caffeine benefits in heart health

As explained above, there are distinct health effects of caffeine on heart health depending if you are a slow or fast metabolizer. Heart health benefits of caffeine only apply to fast metabolizers.

For medium to high caffeine users, those that can handle larger amounts of caffeine, or fast metabolizers, long term caffeine intake, of about 400mg of caffeine (between 3-5 cups of coffee daily), shows the largest reduction on cardiovascular disease risk. For this group, there is a 22% lower risk of heart attack by having 200-300mg caffeine per day (2-3 cups of coffee).

The risk doesn’t increase even with larger amounts of coffee. (7, 8)

To see the effects of caffeine on slow metabolizers, please see the above section listing negative effects.

Caffeine benefits in skin cancer

Two recent, large studies on the effects of coffee on skin cancer have found that caffeinated coffee consumption is associated with a reduction of a risk of malignant melanoma by up to 25%.

Because decaffeinated coffee didn’t show a significant association with the risk of melanoma, scientists think that this may be due to caffeine. More studies on caffeine are planned to confirm these theories. (9, 10)

Caffeine benefits in depression

Several observational studies show that higher caffeine users (especially in coffee) have a decreased risk of depression and depression related suicides. An amount of caffeine of about 400mg (equivalent to 4-5 coffees) is the most optimal in risk reduction and is associated with 20% lower risk of developing depression and 53% lower suicide risk.

However, the risk increases with a usage of 800mg of caffeine per day or more (at least 8 cups of coffee per day) (11, 12, 13, 14).

Caffeine benefits in Alzheimer’s disease

Caffeine consumption has been shown to reduce the risk of developing Alzheimer’s disease. (15, 16, 17)

Caffeine benefits in Parkinson’s disease

Caffeinated coffee drinkers have a 31% decreased risk of developing Parkinson’ disease. (18, 19, 20, 21)

Caffeine benefits in dementia

Caffeine intake reduces the risk of developing dementia. Scientists believed that factors responsible for this reduction may be due to caffeine, antioxidant capacity and increase of insulin sensitivity. (22, 23)

Caffeine benefits in multiple sclerosis (MS)

Studies on the association of caffeine and MS are still inconclusive. Some observational studies show no association, while the most recent study, from 2016, found a correlation between high consumption of caffeinated coffee and about 30% of decreased risk of multiple sclerosis.

This is thought to be due to the caffeine’s neuroprotective properties, and its ability to suppress pro-inflammatory cytokine production. More studies are needed, however, to confirm these findings of caffeine involvement. (24)

Caffeine benefits in physical performance of the athletes

Caffeine (specifically as a capsule/tablet or powder) when taken before exercise, is effective in increasing physical performance (especially in high-intensity workouts of prolonged duration).

It improves performance by acting on several areas in the body: it increases focus and alertness, boosts energy, causes a higher release of epinephrine (adrenaline), increases the release of body fat for energy usage and aids in burning more fatty acids during exercise.

For optimal absorption, it is advisable to take the supplement 60 minutes before the exercise. However, it is also effective when taken 15-30 minutes before exercise. Studies are inconsistent on the effectiveness of caffeine in strength-power exercises. (25, 26)

Caffeine benefits in type 2 diabetes

Habitual caffeine consumption may reduce the risk of diabetes mellitus. (27, 28, 29, 30)

Caffeine benefits in liver health (cirrhosis)

Caffeine in synergy with other compounds present in coffee may have protective properties against alcoholic and non-alcoholic cirrhosis, and reduce the mortality risk from cirrhosis. (31, 32, 33)


You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.

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