17 Caffeine Side Effects That Everyone Should Know About

Unfortunately, your morning cup of joe can do you more harm than good.

Medically reviewed by Reda Elmardi, RDN Reda Elmardi Reda ElmardiRDN facebook_iconinsta_icon
Written by , BSc, Professional Certificate in Food, Nutrition and Health Ravi Teja Tadimalla BSc, Professional Certificate in Food, Nutrition and Health Experience: 8 years
Edited by , BA (Literature & Psychology), PG Diploma Arshiya Syeda BA (Literature & Psychology), PG Diploma Experience: 7 years
Fact-checked by , BEd, MSc (Microbiology), Diploma In Nutrition Aparna Mallampalli BEd, MSc (Microbiology), Diploma In Nutrition Experience: 5 years

The side effects of caffeine come into the picture when the intake goes out of your control. Yes, it has stimulating properties, but many studies suggest that indiscriminate coffee intake may also cause sleep disturbances and induce anxiety in some individuals (1).

What is more disturbing is that caffeine is addictive and may sometimes result in side effects even when consumed in safer dosages. This article explains the 17 ways excess caffeine intake can negatively impact your body, its withdrawal symptoms, and the recommended dosage. Read on!

protip_icon Know The Flip Side: Caffeine

Short-Term Effects
Headache, insomnia, stomach disorders, anxiety attacks, and increased blood pressure.

Long-Term Effects
Increased risk of cardiovascular disease, miscarriage, increased risk of urinary incontinence, and osteoporosis.

Drug Interactions
May interact with blood thinners and antidepressants.

When To See A Doctor
If you experience severe headaches, shortness of breath, severe stomach pain, and heart palpitations.

Caffeine – A Brief

Caffeine is well known as an instant energy booster. It helps people fight drowsiness. Yet there is a lot of controversy surrounding its dosage and effectiveness.

Caffeine, scientifically known as methyl theobromine, is an alkaloid. This natural substance is found in many plants, including coffee beans, tea, kola nuts, and cacao pods. This alkaloid is an important part of the commercial platform, and its man-made form is widely used in the production of pharmacy drugs, drinks, chocolates, and coffee infusions.

protip_icon Did You Know?
Caffeine also occurs naturally in guarana seeds (a type of fruit tree seed that can be cooked until powdered) and leaves of Ilex paraguariensis (a plant used to make yerba mate, a herbal tea).

According to studies, caffeine is the most widely consumed psychostimulanti  A drug or a substance that can enhance mood and mental alertness and may reduce depression and fatigue. in the world (2). This shows how it is also likely to be over-consumed.

A study conducted on 26,680 U.S. service members showed that 87% of them consumed caffeinated products more than once a week. Out of these, coffee had 68% usage, sodas had 42% usage, energy drinks and teas had 29% usage each, and caffeinated gum had 4% usage.

How Does Caffeine Affect Our Body?

As it is water-soluble, caffeine is readily absorbed in our system. It reaches our bloodstream in no time, starting from the stomach to the brain. Does it have any side effects? Read on to know. 

Caffeine Side Effects

  1. May Induce Anxiety Attacks
  2. May Cause Stomach Disorders
  3. May Cause Insomnia
  4. May Cause Miscarriage
  5. May Increase Blood Pressure Levels
  6. May Induce Menstrual Problems
  7. May Increase The Risk Of Urinary Incontinence
  8. Might Cause Weight Gain
  9. May Cause Hallucinations
  10. May Increase The Chances Of Osteoporosis
  11. May Interfere With Estrogen Production
  12. Can Increase The Chance Of Breast Tissue Cysts
  13. May Not Be Good For Individuals With Type 2 Diabetes
  14. Can Inhibit Collagen Production In The Skin
  15. May Impair Hearing Loss Recovery
  16. May Trigger Acne
  17. May Cause Allergies

Its addictive nature makes caffeine a big risk, especially among teenagers and adults. The widely experienced symptoms of too much caffeine in the body include dehydration, excessive production of urine leading to dehydration, stomach disorders, nausea, increased blood pressure, depression, restlessness, jitters, 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

Woman facing anxiety attack as a side effect of caffeine
Image: Shutterstock

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 mood swings, 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 refluxi  A chronic condition that occurs when the stomach acid consistently goes back into the esophagus, the pipe connecting the throat to the stomach. (4). Anecdotal evidence suggests that too much caffeine may also lead to digestive issues and stomach disorders, such as 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

Woman facing insomnia as a side effect of caffeine
Image: Shutterstock

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 tremors, sleeplessness and palpitations (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

Woman facing menstrual problems as a side effect of caffeine
Image: Shutterstock

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 vasomotori  A type of temperature dysfunction caused by hormonal changes and may cause symptoms like hot flashes and night sweats. 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

Woman facing unwanted weight gain as a side effect of caffeine
Image: Shutterstock

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 dizziness, 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 estrogeni  This female sex hormone regulates the reproductive system and is responsible for the development of secondary sex characteristics. 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 collageni  A protein produced by the body that provides structure to the skin and connective tissues and is also used in cosmetic treatments. 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

Woman facing acne as a side effect of caffeine
Image: Shutterstock

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.

Symptoms Of Caffeine Withdrawal

According to research, more than 68 million Americans are caffeine-dependent.

But why do we get addicted to caffeine?

Caffeine is a smart drug. It suppresses adenosine, a chemical produced by the brain that relaxes our body. It leads to a tense surge of energy in our system. This, in turn, forces our brain to demand increased levels of caffeine to stimulate the same reaction. Thus, caffeine dependence and addiction develop. These are the caffeine side effects on the brain.

People who try to get off caffeine experience a lot of withdrawal symptoms. These symptoms are generally mild but can also be fatal for those who are highly accustomed to caffeine.

The general short-term withdrawal symptoms include (24):

  • Headache
  • Nausea
  • Irritability
  • Vomiting
  • Grogginess
  • Lethargy
  • Muscle pain and muscle twitching
  • Depression
  • Lack of concentration

John B, a blogger, recounted how he suffered from caffeine withdrawal. He shared that he used to drink a lot of tea with a good amount of caffeine, so during his recovery, post hospitalization, he suffered from caffeine withdrawal. He writes, “Quitting gave me a 24/7 headache for three consecutive days, a horrible headache… But I didn’t get better, my fatigue became worse and my head more densely clouded (i).”

Recommended Dosage Of Caffeine

Caffeine, with its taste and neuropsychiatric effectsi  Refers to effects, like increased alertness, sleeplessness, and anxiety, that may affect behavior and cognition. , has claimed a prominent place in our lives. Whether it is in chocolates or your morning beverage, it is almost impossible to avoid it. But there’s an important question we need to consider – how much of caffeine is too much?

Caffeine is a drug. Just like other allopathic drugs, caffeine can also affect people differently. Always remember that any pre-existing medical condition can add to the negative effects of caffeine. Thus, to avoid the side effects of caffeine, knowing the condition of your body, medical history, and daily intake is important. In fact, half the troubles associated with this drug can be diminished by keeping a tab on the quantity consumed daily.

What is the safe limit for caffeine?

A healthy adult can consume up to 400 mg (about 4 cups of coffee, or 10 cans of aerated caffeinated drinks) of caffeine daily without worrying about the side effects (24). However, this upper limit is highly dependent on your present health condition and other medications you are on.

protip_icon Quick Tip
You can replace your favorite caffeinated beverage with something healthier like water, green or black tea, or herbal tea.

Children under the age of five should avoid caffeine. Teenagers and young adults should not go for more than 100 mg of caffeine daily.

Infographic: 8 Adverse Ways Caffeine May Affect You

While caffeine is widely consumed for its stimulating effects, it is important to be aware of its potential side effects. Excessive consumption may cause insomnia and lead to restlessness. Check out the infographic below to help you understand the negative effects of caffeine on your body before consuming it.

8 side effects of caffeine (infographic)

Illustration: StyleCraze Design Team

Caffeine is a common ingredient in teas, coffees, and chocolates. However, it is important to note that taking high amounts of caffeine can have adverse effects. Individuals with heart problems, weakened bones, and diabetes should avoid consuming caffeine as some may experience hallucinations, insomnia, or weight gain. Caffeine may also induce anxiety or cause allergies or acne in others. Excess intake of coffee or other caffeine beverages may cause menstrual problems, and hinder estrogen production in women. To avoid such side effects of coffee in females, it is important to consume it in moderation if one cannot completely avoid it.

Frequently Asked Questions

Does caffeine cause dehydration and dry mouths?

Caffeine is a natural diuretic. Some theories suggest that caffeine causes too much fluid to leave the system, resulting in dehydration and a dry mouth. Some also believe that having caffeine is not a good idea while working out as it can cause excessive dehydration. However, research is limited.

In fact, one study states that there could be no link between caffeine intake and dehydration or dry mouth (25).

Does caffeine increase the risk of gout?

Research is limited here. Conversely, some research suggests that long-term caffeine intake may reduce the risk of gout (26). To be on the safe side, if you have gout, please consult your doctor before consuming caffeine. 

What are the different ways to reduce caffeine intake?

One should never quit caffeine abruptly. It may lead to severe withdrawal symptoms, especially if you are habituated to caffeine.

A better solution is to go for a step-by-step reduction method. Begin by cutting down on the number of cups you take in a day. Continue this for a few months until you are sure you won’t cheat. Then, start replacing this high-caffeine beverage with something healthier, like green or white tea and organic fruit juice. Keep your physician in the loop at all times.

Can we take supplements along with caffeine?

You are allowed to take certain supplements along with caffeine, especially those that are known to help cleanse the colon, stimulate digestive enzymes, and rehydrate cells. However, one must avoid herbs and supplements that are known to increase the risk of bleeding. Do consult your doctor before going for drugs and supplements as your medical history may aggravate the problem.

How much caffeine is found in chocolates and beverages?

Coffee is known to contain the maximum amount of caffeine. The quantity of caffeine, however, is highly dependent on the brewing method, the strength of the brew, type of coffee bean, and the cup size. A typical 250 ml cup of black coffee contains about 85 mg of caffeine. A single espresso shot has about 63 mg caffeine, while one cup of decaf coffee contains about 3 mg caffeine.

How do you flush out caffeine?

Start to consume cold caffeinated drinks with water. Once the caffeine has entered your system, the only way to get rid of it is to wait for it to naturally flush out from your body.

How long does it take to detox from caffeine?

How long caffeine lasts in the body varies from person to person. Kiran Campbell, a registered dietitian, says, “Caffeine is actually a drug which affects your body’s central nervous system. And while it reaches its peak potential within 30-45 minutes of being consumed, it is also quickly eliminated from your body within 4-6 hours.”

Why am I suddenly sensitive to caffeine?

A variety of factors can cause caffeine sensitivity, including your liver’s inability to metabolize caffeine. Visit your doctor should you experience any adverse symptoms.

What foods counteract caffeine?

Slow-digesting foods that are high in fiber, like lentils, nuts, beans, and starchy vegetables, may counteract caffeine. They help slow down the release of caffeine into your bloodstream.

On the other hand, an 8-ounce can of red bull contains about 78-80 mg of caffeine. A cup of green tea is known to contain 20-45 mg of caffeine. Cola contains about 30-48 mg of caffeine per can.
Like coffee, the caffeine content in chocolates is also highly dependent on its type. A bar of milk chocolate contains about 1.4 mg of caffeine, which can go as high as 70 mg for a typical dark chocolate bar.

Key Takeaways

  • Excess caffeine consumption can lead to a variety of issues like anxiety, stress, acne, and skin allergies.
  • Pregnant women should avoid caffeine as it may increase the heart rate and metabolism of the fetus or result in delayed fetal growth.
  • Those trying to break away from a caffeine dependency may experience withdrawal symptoms like headaches, irritability, lethargy, and muscle pain.
  • Adults should limit their caffeine consumption to 400 mg, while teenagers and young adults should limit their intake to 100 mg.

Curious about the effects of caffeine on your health? Watch this video to find out if it’s bad for you and make an informed decision.

Personal Experience: Source


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

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  19. NIH Study shows caffeine consumption linked to estrogen changes, National Institutes of Health.
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Reda Elmardi

Reda ElmardiRDN

Reda Elmardi is a registered dietician, certified nutritionist, and certified strength and conditioning specialist trainer. He has more than 10 years of experience and has been an NSCA Certified Strength and Conditioning Specialist Trainer since 2015. He shares sports nutrition tips and gives guidance on exercises, sports, and martial arts through his website. Reda is a Brazilian jiu-jitsu brown belt,...read full bio

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