Why does caffeine consumption cause one to urinate more?

Why does caffeine consumption cause one to urinate more?

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What is the physiological mechanism behind the diuretic effect of caffeine?

Caffeine inhibits the secretion of the antidiuretic hormone (ADH), so it increases diuresis, but this effect is small and transient.

Caffeine in amounts up to 400 mg/day (~4 cups of coffee) does not results in net dehydration, since the amount of water lost due to slightly increased diuresis is much smaller than the amount of water in coffee.

In some people, caffeine may irritate the bladder and thus trigger more frequent urination, but this is not increased diuresis and the total volume of the urine is not increased.

Is Caffeine Bad for People With Inflammatory Bowel Disease?

Robert Burakoff, MD, MPH, is board-certified in gastroentrology. He is the vice chair for ambulatory services for the department of medicine at Weill Cornell Medical College in New York.

A stimulant found in many different foods and beverages, caffeine affects the body in several ways. Most people know that caffeine is found in coffee, tea, and cola drinks, but it can also be present in chocolate, coffee-flavored ice cream or frozen yogurt, energy drinks, and some medications (over-the-counter painkillers in particular). As many as 85 percent of adults in the United States consume caffeine on a daily basis.   In the rest of the world, the percentage of people who use caffeine jumps to 90 percent.

People with inflammatory bowel disease (IBD), a chronic digestive disease, may wonder whether caffeine consumption is safe for them. Caffeine does have certain effects on health, but it is also important to pay attention to the method of delivery. The food or drink containing the caffeine can have a big impact on the symptoms of IBD. As with most things related to diet, moderation is key, and caffeine consumption is no different.

Is Caffeine a Cause of Urinary Incontinence?

According to the International Continence Society (ICS), incontinence is the “involuntary loss of urine that is a social or hygienic problem and is objectively demonstrable.” Urinary incontinence is most commonly a result of bladder dysfunction, sphincter dysfunction, or a combination of both. An estimated 30 to 40 percent of middle-aged women and 50 percent of older women experience urinary leakage.

The problem is less common in men, but does increase with age. Even so, older men experience severe urinary incontinence at only about half the rate of women. Despite the prevalence of this health problem, it is still a “don’t ask, don’t tell” issue.

“In our study of nurses, less than 50 percent of the women who had incontinence reported it to their doctors,” says Mary Townsend, an epidemiologist at Brigham and Women’s Hospital in Boston.

It is a sensitive issue, for sure, but what is the cause of urinary incontinence? Leaks are more common in women who are older, heavier, or smokers, and in those who have had more children, diabetes, or a hysterectomy.

Caffeine may also be a cause of urinary incontinence

“We found a moderate increased risk of developing at least weekly incontinence in caffeine consumers, but only in women who consumed at least 450 milligrams a day,” says Townsend. You’d get 420 mg in one Starbucks venti coffee (24 ounces) and 520 mg in two tall coffees (12 ounces each).

“Caffeine was related only to urgency incontinence—leaks that occur with a sudden need to go to the bathroom—not with stress incontinence,” she notes. That’s a leak that typically occurs with coughing or exercise.

Caffeine is linked to urinary incontinence in men, too. In a nationally representative study of U.S. adults during 2005-2008, men who consumed at least 250 mg or more of caffeine a day were 72 percent more likely to experience moderate to severe urinary incontinence than men who consumed little daily caffeine.

Avoiding caffeine may help. In a small 2014 study in the United Kingdom, eleven women newly diagnosed with an overly active bladder consumed caffeinated drinks for two weeks and decaffeinated drinks for two weeks in random order while keeping three-day diaries about their symptoms. Their sense of urgency and their frequency of urination declined significantly during the weeks consuming decaffeinated beverages. More research with larger numbers of patients is needed.

How might caffeine cause urinary incontinence?

A diuretic increases the amount of urine created by the kidneys. The most commonly known diuretics include coffee, tea, and beer.

“And in animal studies, caffeine increases the force of muscle contractions in the bladder,” says Townsend. “So the combination may lead to urgency.”

Three ways to treat urinary incontinence naturally

1. Kegel Excercises

Training women to contract their pelvic-floor muscles—using Kegel exercises—makes a difference. Kegel exercises are usually recommended during pregnancy, but are also useful for decreasing urinary incontinence.

  • Locate the correct pelvic floor muscles by stopping urination mid-stream. Regularly stopping urination is not recommended, as it can weaken the pelvic floor muscles, however it is a great way to locate the correct muscles.
  • With an empty bladder, tighten your pelvic floor muscles and hold the contraction for five seconds, followed by five seconds of relaxation. Repeat this four or five times in a row, and eventually work up to maintaining the contraction for ten seconds.
  • Try to breathe normally and focus just on the pelvic floor muscles.
  • The goal is to work up to ten repetitions, three times per day.

2. Losing weight

Obesity is possibly a major cause of urinary incontinence, with demonstrated associations between body mass index (BMI) and risk of urinary incontinence. For overweight patients, losing weight is the number one recommendation for treating urinary incontinence.

Walking or other moderate exercise may lower the risk, especially of stress incontinence, says Townsend, “in part by maintaining a healthy weight and possibly also by strengthening the pelvic-floor muscles.”

So for caffeine lovers, the news is not all bad. It is worth noting, though, that caffeine consumption, in conjunction with other risk factors, may increase your chances of developing urinary incontinence.

Do you know someone with urinary incontinence? What has helped?

Sources: Am. J. Obstet. Gynecol. 194: 339, 2006 J. Urol. 185: 1775, 2011 Int. Urogynecol. J. 24: 605, 2013 Cochrane Database Syst. Rev.: CD005654, 2010 N. Engl. J. Med. 360: 481, 2009 J. Urol. 189: 2170, 2013 J. Wound Ostomy Continence Nurs. 41: 371, 2014.

This post was originally published in 2014 and is updated regularly.

Regular Caffeine Consumption – From Coffee, Cola, or Energy Drinks – Affects Brain Structure

Coffee, cola or an energy drink: caffeine is the world’s most widely consumed psychoactive substance. Researchers from the University of Basel have now shown in a study that regular caffeine intake can change the gray matter of the brain. However, the effect appears to be temporary.

No question – caffeine helps most of us to feel more alert. However, it can disrupt our sleep if consumed in the evening. Sleep deprivation can in turn affect the gray matter of the brain, as previous studies have shown. So can regular caffeine consumption affect brain structure due to poor sleep? A research team led by Dr. Carolin Reichert and Professor Christian Cajochen of the University of Basel and UPK (the Psychiatric Hospital of the University of Basel) investigated this question in a study.

The result was surprising: the caffeine consumed as part of the study did not result in poor sleep. However, the researchers observed changes in the gray matter, as they report in the journal Cerebral Cortex. Gray matter refers to the parts of the central nervous system made up primarily of the cell bodies of nerve cells, while white matter mainly comprises the neural pathways, the long extensions of the nerve cells.

The daily dose of caffeine is part everyday life for many people. Apparently, however, regular caffeine consumption alters brain structures.

A group of 20 healthy young individuals, all of whom regularly drink coffee on a daily basis, took part in the study. They were given tablets to take over two 10-day periods, and were asked not to consume any other caffeine during this time. During one study period, they received tablets with caffeine in the other, tablets with no active ingredient (placebo). At the end of each 10-day period, the researchers examined the volume of the subjects’ gray matter by means of brain scans. They also investigated the participants’ sleep quality in the sleep laboratory by recording the electrical activity of the brain (EEG).

Sleep unaffected, but not gray matter

Data comparison revealed that the participants’ depth of sleep was equal, regardless of whether they had taken the caffeine or the placebo capsules. But they saw a significant difference in the gray matter, depending on whether the subject had received caffeine or the placebo. After 10 days of placebo – i.e. “caffeine abstinence” – the volume of gray matter was greater than following the same period of time with caffeine capsules.

The difference was particularly striking in the right medial temporal lobe, including the hippocampus, a region of the brain that is essential to memory consolidation. “Our results do not necessarily mean that caffeine consumption has a negative impact on the brain,” emphasizes Reichert. “But daily caffeine consumption evidently affects our cognitive hardware, which in itself should give rise to further studies.” She adds that in the past, the health effects of caffeine have been investigated primarily in patients, but there is also a need for research on healthy subjects.

Although caffeine appears to reduce the volume of gray matter, after just 10 days of coffee abstinence it had significantly regenerated in the test subjects. “The changes in brain morphology seem to be temporary, but systematic comparisons between coffee drinkers and those who usually consume little or no caffeine have so far been lacking,” says Reichert.

Reference: “Daily Caffeine Intake Induces Concentration-Dependent Medial Temporal Plasticity in Humans: A Multimodal Double-Blind Randomized Controlled Trial” by Yu-Shiuan Lin, Janine Weibel, Hans-Peter Landolt, Francesco Santini, Martin Meyer, Julia Brunmair, Samuel M Meier-Menches, Christopher Gerner, Stefan Borgwardt, Christian Cajochen and Carolin Reichert, 15 February 2021, Cerebral Cortex.
DOI: 10.1093/cercor/bhab005


Many of us can’t imagine starting the day without a cup of coffee. One reason may be that it supplies us with a jolt of caffeine, a mild stimulant to the central nervous system that quickly boosts our alertness and energy levels. [1] Of course, coffee is not the only caffeine-containing beverage. Read on to learn more about sources of caffeine, and a review of the research on this stimulant and health.

Absorption and Metabolism of Caffeine

The chemical name for the bitter white powder known as caffeine is 1,3,7 trimethylxanthine. Caffeine is absorbed within about 45 minutes after consuming, and peaks in the blood anywhere from 15 minutes to 2 hours. [2] Caffeine in beverages such as coffee, tea, and soda is quickly absorbed in the gut and dissolves in both the body’s water and fat molecules. It is able to cross into the brain. Food or food components, such as fibers, in the gut can delay how quickly caffeine in the blood peaks. Therefore, drinking your morning coffee on an empty stomach might give you a quicker energy boost than if you drank it while eating breakfast.

Caffeine is broken down mainly in the liver. It can remain in the blood anywhere from 1.5 to 9.5 hours, depending on various factors. [2] Smoking speeds up the breakdown of caffeine, whereas pregnancy and oral contraceptives can slow the breakdown. During the third trimester of pregnancy, caffeine can remain in the body for up to 15 hours. [3]

People often develop a “caffeine tolerance” when taken regularly, which can reduce its stimulant effects unless a higher amount is consumed. When suddenly stopping all caffeine, withdrawal symptoms often follow such as irritability, headache, agitation, depressed mood, and fatigue. The symptoms are strongest within a few days after stopping caffeine, but tend to subside after about one week. [3] Tapering the amount gradually may help to reduce side effects.

Sources of Caffeine

Caffeine is naturally found in the fruit, leaves, and beans of coffee, cacao, and guarana plants. It is also added to beverages and supplements. There is a risk of drinking excess amounts of caffeinated beverages like soda and energy drinks because they are taken chilled and are easy to digest quickly in large quantities.

  • Coffee. 1 cup or 8 ounces of brewed coffee contains about 95 mg caffeine. The same amount of instant coffee contains about 60 mg caffeine. Decaffeinated coffee contains about 4 mg of caffeine. Learn more about coffee.
  • Espresso. 1 shot or 1.5 ounces contains about 65 mg caffeine.
  • Tea. 1 cup of black tea contains about 47 mg caffeine. Green tea contains about 28 mg. Decaffeinated tea contains 2 mg, and herbal tea contains none. Learn more about tea.
  • Soda. A 12-ounce can of regular or diet dark cola contains about 40 mg caffeine. The same amount of Mountain Dew contains 55 mg caffeine.
  • Chocolate (cacao). 1 ounce of dark chocolate contains about 24 mg caffeine, whereas milk chocolate contains one-quarter of that amount.
  • Guarana. This is a seed from a South American plant that is processed as an extract in foods, energy drinks, and energy supplements. Guarana seeds contain about four times the amount of caffeine as that found in coffee beans. [4] Some drinks containing extracts of these seeds can contain up to 125 mg caffeine per serving.
  • Energy drinks. 1 cup or 8 ounces of an energy drink contains about 85 mg caffeine. However the standard energy drink serving is 16 ounces, which doubles the caffeine to 170 mg. Energy shots are much more concentrated than the drinks a small 2 ounce shot contains about 200 mg caffeine. Learn more about energy drinks.
  • Supplements. Caffeine supplements contain about 200 mg per tablet, or the amount in 2 cups of brewed coffee.

Recommended Amounts

In the U.S., adults consume an average of 135 mg of caffeine daily, or the amount in 1.5 cups of coffee (1 cup = 8 ounces). [5] The U.S. Food and Drug Administration considers 400 milligrams (about 4 cups brewed coffee) a safe amount of caffeine for healthy adults to consume daily. However, pregnant women should limit their caffeine intake to 200 mg a day (about 2 cups brewed coffee), according to the American College of Obstetricians and Gynecologists.

The American Academy of Pediatrics suggests that children under age 12 should not consume any food or beverages with caffeine. For adolescents 12 and older, caffeine intake should be limited to no more than 100 mg daily. This is the amount in two or three 12-ounce cans of cola soda.

Caffeine and Health

Caffeine is associated with several health conditions. People have different tolerances and responses to caffeine, partly due to genetic differences. Consuming caffeine regularly, such as drinking a cup of coffee every day, can promote caffeine tolerance in some people so that the side effects from caffeine may decrease over time. Although we tend to associate caffeine most often with coffee or tea, the research below focuses mainly on the health effects of caffeine itself. Visit our features on coffee, tea, and energy drinks for more health information related to those beverages.

Caffeine can block the effects of the hormone adenosine, which is responsible for deep sleep. Caffeine binds to adenosine receptors in the brain, which not only lowers adenosine levels but also increases or decreases other hormones that affect sleep, including dopamine, serotonin, norepinephrine, and GABA. [2] Levels of melatonin, another hormone promoting sleep, can drop in the presence of caffeine as both are metabolized in the liver. Caffeine intake later in the day close to bedtime can interfere with good sleep quality. Although developing a caffeine tolerance by taking caffeine regularly over time may lower its disruptive effects, [1] those who have trouble sleeping may consider minimizing caffeine intake later in the day and before going to bed.

In sensitive individuals, caffeine can increase anxiety at doses of 400 mg or more a day (about 4 cups of brewed coffee). High amounts of caffeine may cause nervousness and speed up heart rate, symptoms that are also felt during an anxiety attack. Those who have an underlying anxiety or panic disorder are especially at risk of overstimulation when overloading on caffeine.

Caffeine stimulates the heart, increases blood flow, and increases blood pressure temporarily, particularly in people who do not usually consume caffeine. However, strong negative effects of caffeine on blood pressure have not been found in clinical trials, even in people with hypertension, and cohort studies have not found that coffee drinking is associated with a higher risk of hypertension. Studies also do not show an association of caffeine intake and atrial fibrillation (abnormal heart beat), heart disease, or stroke. [3]

Caffeine is often added to weight loss supplements to help “burn calories.” There is no evidence that caffeine causes significant weight loss. It may help to boost energy if one is feeling fatigued from restricting caloric intake, and may reduce appetite temporarily. Caffeine stimulates the sympathetic nervous system, which plays a role in suppressing hunger, enhancing satiety, and increasing the breakdown of fat cells to be used for energy. [6] Cohort studies following large groups of people suggest that a higher caffeine intake is associated with slightly lower rates of weight gain in the long term. [3] However, a fairly large amount of caffeine (equivalent to 6 cups of coffee a day) may be needed to achieve a modest increase in calorie “burn.” Additional calories obtained from cream, milk, or sweetener added to a caffeinated beverage like coffee or tea can easily negate any calorie deficit caused by caffeine.

Caffeine can cross the placenta, and both mother and fetus metabolize caffeine slowly. A high intake of caffeine by the mother can lead to prolonged high caffeine blood levels in the fetus. Reduced blood flow and oxygen levels may result, increasing the risk of miscarriage and low birth weight. [3] However, lower intakes of caffeine have not been found harmful during pregnancy when limiting intakes to no more than 200 mg a day. A review of controlled clinical studies found that caffeine intake, whether low, medium, or high doses, did not appear to increase the risk of infertility. [7]

Most studies on liver disease and caffeine have specifically examined coffee intake. Caffeinated coffee intake is associated with a lower risk of liver cancer, fibrosis, and cirrhosis. Caffeine may prevent the fibrosis (scarring) of liver tissue by blocking adenosine, which is responsible for the production of collagen that is used to build scar tissue. [3]

Studies have shown that higher coffee consumption is associated with a lower risk of gallstones. [8] Decaffeinated coffee does not show as strong a connection as caffeinated coffee. Therefore, it is likely that caffeine contributes significantly to this protective effect. The gallbladder is an organ that produces bile to help break down fats consuming a very high fat diet requires more bile, which can strain the gallbladder and increase the risk of gallstones. It is believed that caffeine may help to stimulate contractions in the gallbladder and increase the secretion of cholecystokinin, a hormone that speeds the digestion of fats.

Caffeine may protect against Parkinson’s disease. Animal studies show a protective effect of caffeine from deterioration in the brain. [3] Prospective cohort studies show a strong association of people with higher caffeine intakes and a lower risk of developing Parkinson’s disease. [9]

Caffeine has a similar action to the medication theophylline, which is sometimes prescribed to treat asthma. They both relax the smooth muscles of the lungs and open up bronchial tubes, which can improve breathing. The optimal amount of caffeine needs more study, but the trials reviewed revealed that even a lower caffeine dose of 5 mg/kg of body weight showed benefit over a placebo. [10] Caffeine has also been used to treat breathing difficulties in premature infants. [3]

Caffeine stimulates the release of a stress hormone called epinephrine, which causes liver and muscle tissue to release its stored glucose into the bloodstream, temporarily raising blood glucose levels. However, regular caffeine intake is not associated with an increased risk of diabetes. In fact, cohort studies show that regular coffee intake is associated with a lower risk of type 2 diabetes, though the effect may be from the coffee plant compounds rather than caffeine itself, as decaffeinated coffee shows a similar protective effect. [3] Other observational studies suggest that caffeine may protect and preserve the function of beta cells in the pancreas, which are responsible for secreting insulin. [11]

Signs of Toxicity

Caffeine toxicity has been observed with intakes of 1.2 grams or more in one dose. Consuming 10-14 grams at one time is believed to be fatal. Caffeine intake up to 10 grams has caused convulsions and vomiting, but recovery is possible in about 6 hours. Side effects at lower doses of 1 gram include restlessness, irritability, nervousness, vomiting, rapid heart rate, and tremors.

Toxicity is generally not seen when drinking caffeinated beverages because a very large amount would need to be taken within a few hours to reach a toxic level (10 gm of caffeine is equal to about 100 cups of brewed coffee). Dangerous blood levels are more often seen with overuse of caffeine pills or tablets. [3]

Athletic Performance

Caffeine is commonly used in athletics as an “ergogenic aid” (i.e., performance enhancer) to give them that extra push they need. Because of this, caffeine is found in several sports supplements and pre-workouts. Caffeine has been found to enhance several forms of exercise, including endurance, high-intensity sports, and strength-power performance. These benefits are typically achieved with doses in the range of 250 to 500 mg, consumed around an hour before training. Take into consideration that consuming caffeine while fasted may require lower doses than with food, due to the effect of food on absorption rate.

A synergistic effect of ketone supplements and caffeine may also exist for athletic performance. Ketone supplements alone are increasingly researched in the context of sports performance, and there is evidence to support a possible performance-enhancing effect, especially for endurance exercise. In a recent study, a pre-workout supplement containing both exogenous ketone salts and caffeine (100 mg) was found to increase high-intensity exercise performance in both keto- and non-keto-adapted individuals. If you are using a ketogenic diet or exogenous ketones to enhance your athletic performance, caffeine may provide extra benefits. Unfortunately, this study didn’t compare the effects with and without caffeine, but based on the outcomes of caffeine and ketones alone, it’s certainly not outside the realm of possibility.

How does caffeine affect the body?

Caffeine--the drug that gives coffee and cola its kick--has a number of physiological effects. At the cellular level, caffeine blocks the action of a chemical called phosphodiesterase (PDE). Inside cells, PDE normally breaks down the second chemical messenger cyclic adenosine monophosphate (cAMP). Many hormones and neurotransmitters cannot cross the cell membrane, and so they exert their actions indirectly via such second messengers when they bind to a receptor on the surface of a cell, it initiates a chemical chain reaction called an enzyme cascade that results in the formation of second messenger chemicals.

Historically, cAMP was the first second messenger ever described. Now, however, scientists have identified several major classes of second messengers, which are generally formed in similar ways through a set of molecules called G proteins. The advantage of such a complex system is that an extracellular signal can be greatly amplified in the process, and so have a massive intracellular effect.

Thus, when caffeine stops the breakdown of cAMP, its effects are prolonged, and the response throughout the body is effectively amplified. In the heart, this response prompts norepinephrine--also called noradrenalin--and a related neurotransmitter, epinephrine, to increase the rate and force of the muscle's contractions. Although the two act in concert, norepinephrine is released by sympathetic nerves near the pacemaker tissue of the heart, whereas epinephrine is released primarily by the adrenal glands. These chemical messages lead to "fight or flight" behavior. During stressful or emergency conditions, they raise the rate and force of the heart, thereby increasing the blood pressure and delivering more oxygen to the brain and other tissues.

Caffeine would be expected to have this effect on any animals that used these neurotransmitters to regulate their heartbeat. Generally speaking, the effects of caffeine are most pronounced in birds and mammals. Reptiles have some response, and lower vertebrates and invertebrates have rather small or no responses. From an evolutionary perspective, fish and amphibians don't show as strong a response to epinephrine and norepinephrine as the higher vertebrates, and they lack a well-developed sympathetic (that is, stimulatory) enervation to heart.

Drinking too much caffeine can lead to heartburn

No, it's not just your favorite foods that are causing you to have horrible heartburn. Drinking too much coffee could be doing you in for an uncomfortable evening too. Ugh. Interestingly, the caffeine in your java isn't entirely to blame for your heartburn. "This is not a result of the caffeine content of the food, but more so the acidity as a result of the food processing methods," Gabrielle Tafur, dietitian nutritionist, told Health Digest. These caffeinated concoctions contain acids that relax the lower esophageal sphincter, which connects the throat to the stomach. This can cause it to come back up and trigger acid reflux. Yuck.

If you drink too many caffeinated beverages, you could develop a digestive disorder. "Drinking coffee excessively can worsen gastroesophageal reflux disease [GERD]," Dr. Lina Velikova, immunologist and medical writer, cautioned. If you find yourself hurting from heartburn quite often, cutting back on the caffeine may be the way to go.

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@burcidi-- That's exactly right. Coffee doesn't make the body produce more urine, it just makes urine leave the body faster. It does this by stimulating urination. So that is the reason why coffee doesn't really carry the risk of dehydration like the over-the-counter or prescription diuretics.

@fify-- That's a good question. One reason could be that the type of caffeine in coffee is different than the caffeine in tea. Plus there is just more caffeine in coffee. I can never have coffee at night for this reason, but can have black tea without having any trouble sleeping.

I'm not sure how accurate this is, but I've heard that this diuretic effect of coffee might also be caused, or at least increased by the oils in coffee. Different people might also react to it differently. For example, I don't really drink more water like you do when I have coffee. But coffee does stimulate bowel movements with me, which it may not do for other people. burcidi March 12, 2012

Okay, so, coffee makes us urinate more, but it doesn't increase urine output? How does that work?

Does coffee just quicken urination? The amount of urine that would leave our body by, let's say, midnight, will leave by the afternoon?

Is this what this means? If it is, then coffee is not "diuretic" in the same sense that diuretic water pills are. I believe water pills actually increase urine output (not just quicken it) and they have a risk of dehydration. fify March 11, 2012

I'm a big coffee drinker and I believe that coffee has health benefits. But coffee does make me go to the restroom more because it makes me drink more water.

I had no idea that coffee is diuretic and always wondered why I drink so much water after having coffee. For every one cup of coffee, I have an extra two glasses of water. It's this extra water that makes me go to the bathroom more.

If I didn't drink more water with coffee, I don't think I would go to the restroom more than usual. But I'd probably be dehydrated because it makes me so thirsty!

Black tea makes me thirsty too, but not as much as coffee does even though they both have caffeine. Does anyone know why?

Its addictive nature makes caffeine a big risk, especially among teenagers and adults. The widely experienced side effects of caffeine include dehydration, excessive production of urine leading to dehydration, stomach disorders, nausea, increased blood pressure, depression, restlessness, increased heart rate leading to death, obesity, increased body weight, and fever.

Read on to get a detailed picture of caffeine side effects:

1. May Induce Anxiety Attacks

Excessive intake of caffeine can lead to a serious case of anxiety. Studies done on secondary school children showed that a high intake of caffeine could be associated with feelings of anxiety and stress (3).

A person with anxiety is known to experience nervousness and restlessness, even under normal conditions. Caffeine worsens such conditions (3). Hence, one should be very cautious if they experience these symptoms.

Prevention Method

People with anxiety disorders should consult their physicians before opting for caffeine. This may rule out the chances of drug interactions.

2. May Cause Stomach Disorders

The acids present in caffeine stimulate the stomach to produce more acid. Caffeine (coffee) seems to promote gastroesophageal reflux (4). Anecdotal evidence suggests that too much caffeine may also lead to stomach disorders like nausea, cramps, diarrhea, and bloating.

Prevention Method

If you have a weak stomach, restrict your daily dose of caffeine to two cups (maximum).

3. May Cause Insomnia

Insomnia is a sleep disorder in which a person finds it difficult to fall or stay asleep. It is a withdrawal symptom, which is combined with other physical problems, such as increased fatigue and headache. This is a common sign among those who consume a lot of caffeine.

Such people would experience sleeplessness and irritability if they were to withdraw from caffeine. Though certain studies did not find major effects, the intake of caffeine right before bed has been associated with sleeplessness (5).

Prevention Method

The easiest way to tackle insomnia is by avoiding caffeine before going to bed. Cutting down on the number of cups per day can also help.

4. May Cause Miscarriage

Pregnant women should be extra cautious with caffeine as excessive intake may lead to miscarriage and other pre-delivery complications (6).

Caffeine is water-soluble and easily crosses the placenta through the bloodstream. As it is a stimulant, it can cause a rapid increase in the heart rate and metabolism of the fetus. One of the side effects of too much caffeine includes delayed fetal growth (7).

Breastfeeding mothers should not consume more than two cups of coffee per day as it affects the baby directly by causing physical irritability. It may also affect iron status in the infant (8).

Prevention Method

Consult your family physician before you decide to take caffeine regularly. Under any circumstances, would-be mothers should not take more than 200 mg of caffeine in a day.

5. May Increase Blood Pressure Levels

People who have hypertension should be cautious about the amount of caffeine they consume on a daily basis.

Caffeine is known to spike your blood pressure for a short time (9). While there are no long-term effects of caffeine, some believe it may worsen the condition in people with irregular heart rhythms. On the other hand, certain studies state that the intake of coffee is not linked to hypertension (10). Hence, more research is needed to establish a connection.

Caffeine is also associated with a heart attack in young adults. According to a study, young adults with mild hypertension who consume more than four cups of coffee in a day are four times more vulnerable to heart attack than those who consume two cups or less (11).

Prevention Method

If you have hypertension or cardiovascular problems, it is better to seek a medical opinion before including caffeine in your daily routine.

6. May Induce Menstrual Problems

While a hot cup of coffee feels great during those days, excessive intake of caffeine can meddle with your menstrual cycle. It can cause period delays, excessive flow, and prolonged cramps.

Caffeine also increases the chance of vasomotor in menopausal women.

According to a study published in The Journal of The North American Menopause Society, menopausal women who are dependent on caffeine have a greater chance of displaying vasomotor symptoms (12).

Prevention Method

Quantity is key. You should always measure what you consume, whether it is caffeine or not. Consulting a doctor is also an important step, especially if you have menstrual problems.

7. May Increase The Risk Of Urinary Incontinence

Caffeine increases the chances of urinary incontinence in women (13). It is a bladder disorder in which the person loses control of the bladder. It results in the sudden leakage of urine whenever the person laughs, coughs, or sneezes.

Prevention Method

Avoid consuming more than two cups of caffeine in a day.

8. Might Cause Weight Gain

Caffeine may induce stress. Animal studies show that stress can lead to obesity (14). However, there is no direct research stating that caffeine can lead to weight gain and long-term obesity.

Some believe that caffeine brings up the levels of stress hormones, which results in increased hunger pangs. This is not proven by research, though.

Prevention Method

Coffee is great. But making it a habit can add extra kilos to your body. Make it a point to have no more than two-three cups of caffeine in a day, and that includes coffee, cola, chocolate, and tea.

9. May Cause Hallucinations

It is true that caffeine can make you high. If you go overboard, you may experience confusion and hallucinations. These effects were more pronounced in those taking more than seven cups of coffee (more than 300 mg of caffeine in a day) (15). In some cases, this has even led to death due to convulsions (16).

Prevention Method

If you feel you are getting addicted to caffeine, start cutting down your daily consumption slowly.

10. May Increase The Chances Of Osteoporosis

Consuming caffeine in large quantities may also increase the risk of osteoporosis. This effect was found to be true in elderly women, whose calcium performance was already impaired (17). It interferes with the absorption of calcium, resulting in bone thinning (osteoporosis), especially in older women whose intake of calcium is below the recommended intake (18).

Overconsumption of caffeine may also cause achy muscles and twitches, though more research is needed to understand this aspect.

Prevention Method

Avoid caffeine if you have calcium deficiency, as it may worsen the condition.

11. May Interfere With Estrogen Production

Caffeine is known to interfere with estrogen production and metabolism. While it increased estrogen production in Asians, it decreased the levels in white females (19).

Some believe that caffeine can reduce a woman’s chances of getting pregnant (the higher the caffeine dependency, the greater the risk), though this has not been proven.

It also is believed that caffeine can have strong effects that may complicate pregnancy. Since research is lacking, we suggest that women who look forward to conceiving consult their doctor before taking caffeine.

Prevention Method

Consult your doctor for the recommended safe dosage of caffeine.

12. Can Increase The Chance Of Breast Tissue Cysts

According to a published study, women who consume more than 500 mg of caffeine per day have twice more chances of developing breast tissue cysts than those who take 31-250 mg of caffeine (20).

Prevention Method

Limit your caffeine intake.

13. May Not Be Good For Individuals With Type 2 Diabetes

If you have type 2 diabetes, you may want to consider limiting your caffeine intake. It may impair glucose metabolism, increasing the risk of diabetes complications (21).

Prevention Method

Consult your physician and get your daily caffeine limit defined.

14. Can Inhibit Collagen Production In The Skin

Caffeine was found to reduce collagen production in human skin (22).

Prevention Method

This problem could be easily prevented by limiting your caffeine dose.

15. May Impair Hearing Loss Recovery

According to a study conducted on guinea pigs, caffeine may also delay the recovery rate of noise-induced hearing loss (23). The same correlation is believed to be observed in humans as well.

Prevention Method

The ideal solution is not to consume more than 400 mg of caffeine in a day.

Insufficient Evidence For The Following

16. May Trigger Acne

Having numerous cups of coffee in a day can also cause acne. Caffeine magnifies the body’s stress levels by boosting stress hormones, which is one of the main reasons for breakouts. Caffeine can also throw your body off balance, causing stress and eventually breakouts.

Prevention Method

If you love your skin and are quite vulnerable to acne breakouts, limit your caffeine intake.

17. May Cause Allergies

Caffeine allergy is highly uncommon, but some people might develop oversensitivity to it. This may cause allergic symptoms, like rashes, hives, and pain.

Prevention Method

If you experience such reactions, it is better to quit caffeine. Seek a doctor’s advice if the problem persists.

Some of the side effects could be quite uncomfortable. But does this mean you need totally abstain from caffeine? Well, doing that too early may lead to caffeine withdrawal, especially if you are used to consuming caffeine on a regular basis.


Centre for Addiction and Mental Health (CAMH). (2011). Caffeine. Retrieved from

Healthline. (2017). The effects of caffeine on your body. Retrieved from

Harm Reduction TO is created within the Dish With One Spoon Territory and the traditional territory of the Mississaugas, Anishnabeg, Chippewa, Haudenosaunee, and Wendat peoples.