20+ Harmful Effects of Caffeine


The harmful effects of caffeine are sometimes harder to find information on than all of the reported positives.

Here are a few of the studies that concluded that caffeine could be potentially dangerous to one’s health.

Research Showing Harmful Effects of Caffeine

  1. More than 4 cups of coffee linked to early death. A Mayo Clinic partnered study found that men who drank more than four 8 fl.oz. cups of coffee had a 21% increase in all-cause mortality. However, those that reported that they consumed excessive amounts of caffeine were also likely to smoke and have poor fitness. Dr. Nancy Snyderman from NBC said there were a few discrepancies with the study, but stresses that moderation is still key. See Her Interview Here.
  2. Caffeine consumption may raise blood pressure. Especially in those already suffering from hypertension and those who don’t normally consume caffeine. People with hypertension were given 250 mg of caffeine (about 2 coffees) and the data revealed that their blood pressure was elevated for about 2-3 hours after the caffeine. Src. A second study performed by The Mayo Clinic found similar results from a 160 mg dose. All participants experienced a marked rise in blood pressure and it was the most pronounced in those that didn’t normally consume caffeine. Src.
  3. Increased risk of heart attacks among young adults. A study conducted by Dr. Lucio Mos found that young adults who were diagnosed with mild hypertension had 4 times the risk of having a heart attack if they consumed the amount of caffeine equivalent to 4 cups of coffee.  More moderate consumption showed 3 times the risk. Src.
  4. Caffeine linked to gout attacks. This study showed that people who binge on caffeinated beverages increase their risk for a gout flare-up. Src.
  5. Breast Tissue Cysts In Women. One study showed that “Women who consumed 31–250 mg of caffeine/day had a 1.5-fold increase in the odds of developing fibrocystic breast disease and women who drank over 500 mg/day had a 2.3-fold increase in the odds of developing cysts. Src.
  6. Caffeine could cause incontinence. A study out of the University of Alabama showed that women who consume a lot of caffeine are 70% more likely to develop incontinence. Src.
  7. Caffeine may cause insomnia. Caffeine in a person’s system at bedtime can mimic the symptoms of insomnia. Src.
  8. Caffeine can cause indigestion. People who consume caffeinated beverages often report an upset stomach or indigestion. This mainly occurs when the beverages are consumed on an empty stomach. Src.
  9. Caffeine can cause headaches. While occasional doses of caffeine can relieve headache symptoms, the overuse of caffeine can cause headaches and lead to migraines. Src.
  10. Caffeine could reduce fertility in women. A study from The University of Nevada School of Medicine showed that caffeine can reduce a woman’s chances of becoming pregnant by about 27%. Src.
  11. Caffeine and Miscarriage Risk: In a recent study, both men and women who consumed at least two caffeinated beverages a day during the weeks prior to conception slightly increased the risks of a miscarriage. Src.
  12. Caffeine may not be healthy for type 2 diabetics. A study conducted by the American Diabetes Association showed that caffeine impaired glucose metabolism in those with type 2 diabetes. Src.
  13. Caffeine Overdose. While overdose is rare, it can lead to many adverse symptoms including death, especially in those with underlying medical conditions. Some have a lower tolerance for caffeine than others. Src.
  14. Caffeine Allergies. Some people have over-sensitivity to the caffeine molecule, which causes allergic-like reactions in the body such as hives and pain. Although not a true allergy, many report very negative symptoms after consuming even the smallest amounts. Src.
  15. Caffeine causes more forceful heart contractions. A recent study showed that immediately after energy drink consumption the heart produced more forceful contractions. It is unclear if this has any long-term health implications except for those with known health conditions. Src.
  16. Worse Menopause Symptoms. A recent study published in The Journal of The North American Menopause Society showed that menopausal women who consumed caffeine had a greater degree of vasomotor symptoms. Src.
  17. Caffeine consumption can lead to increased anxiety, depression and the need for anxiety medication. Src and Src. See also our article as to why caffeine causes anxiety and panic attacks.
  18. Caffeine increases the amount of sugary beverages consumed by people, which contributes to obesity and diabetes. Src.
  19. Caffeine inhibits collagen production in the skin. This effect is dose-dependent but really heavy caffeine consumers should be aware. The Study.
  20. Caffeine interferes with ossification and could also lead to greater risk of bone fractures. This is dose dependent, but heavy caffeine consumers should take note. Study 1 (pdf) Study 2.
  21. Caffeine Does Not Help With Prolonged Sleep Deprivation: This can lead to a false sense of security for those that have been sleep deprived for multiple days in a row and choose to get behind the wheel or do some other focus required task, thinking that as long as they have caffeine, they’ll be able to perform. Researchers from the American Academy of Sleep Medicine came to this conclusion after studying caffeine’s effects on their sleep-deprived test subjects. Here’s the study in detail.
  22. Caffeine May Impair Hearing Loss Recovery: For guinea pigs exposed to excessive levels of noise, caffeine was shown to delay the rate at which the guinea pigs recovered from noise-induced hearing loss. Here are the results of a recent study that investigated the problem. A correlation to humans is believed to exist but more research will be needed.

When not managed caffeine can quickly become an out of control problem.

If you are experiencing any tell-tale signs of the risks above, then it’s time to start cutting back. Otherwise, it’s just a matter of time. If cold turkey is no longer a valid approach for you, or if you’ve failed in the past, then we recommend looking at the Wean Caffeine detox. With Wean, you slowly reduce your caffeine intake with their daily supplement protocol and comprehensive caffeine detox book. This may be the best $20 you’ve ever spent.

Other Claims Against Caffeine

You may have heard or read about other negative health effects from caffeine consumption, but as of now, there just isn’t enough evidence to fully endorse those as legitimate health concerns.

Some of those negatives include:

  • Adrenal fatigue
  • Irregular heartbeat
  • Hallucinations
  • Accelerates bone loss. Src.
  • Tremors

Caffeine is a drug and can affect people differently just like any other substance. It’s important that consumers understand how caffeine interacts with their bodies in regards to their personal health histories.

The food and beverage industry spends millions, if not billions, of dollars worldwide to fund studies and promote caffeinated products as safe or even healthy.

Fortunately, caffeine is one of the most researched substances on the planet and there does exist some unbiased data in which to glean some reliable information from.

While much of the research published does allude to the safety and even potential benefits of caffeine (in moderation), there are a handful of research studies that highlight the potentially harmful effects of caffeine.

The risks of suffering from any of the harmful effects of caffeine are diminished by being aware of how much is personally being consumed daily.

It is also important to be aware of any pre-existing medical conditions that may contribute to caffeine’s negative effects.

Get Help Quitting Caffeine

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  • Yes you can stop. And it is ‘hear’ not ‘here’. You’re welcome.

  • Anaiah Jandhi

    Yeah .. maybe stress from work + school + family is different from stress on having kids .. but still it gets into my nerves 🙂

  • Ryan Doyle

    Sounds like famous last words!

  • scw

    When people say sugar they usually mean pure sugar. Pure sugar is not in any way healthy for humans in large amounts. It cause large rapid increases in blood sugar levels which is obviously a problem for diabetics. Over time a high “Sugar” diet will lead to type 2 diabetes because most bodies cant handle consistent crazy insulin spikes in their old age.

    Vegetables have none of these problems. A vegetable typically contains complex carbs not consider a simple sugar and also has a lot of fiber greatly reducing their effects on blood sugar. Pretty much all fruits and vegetables are healthy to consume as you will get full before there is any chance of overeating them.

    Overeating is the fundamental cause of type 2 diabetes. Eating lots of simple sugars tends to trick your body into wanting to eat more when you are not hungry. The healthier and more active you are the more simple sugars you can have in your diet.

    Simple sugars have their uses, like when your body needs boost of energy such as during weight training or a marathon, but when they become a staple of a sedentary person’s diet then you have a problem.

    Fats are not bad for you. There are certain highly processed fats or denatured fats which are bad for you but other sources of natural fat are actually essential. The amount of fat that is healthy in your diet will depend on the amount of energy calories you are able to obtain from starchy carbs. Healthy fats would only be bad for you if they were coupled with overeating.

  • jason

    Actually, this is mostly incorrect. This article lacks legitimate proof, using words like “linked” and “related to” to try and convince parents and concerned adults that caffeine consumption is “deadly”. Most of these studies are very inconclusive and lack a definitive end result. Caffeine is a psychoactive substance, meaning it affects your brain’s perception of energy, and doesn’t provide actual energy in the form of Adenosine Triphosphate. Caffeine makes your brain more alert.

    Also, the average human can consume around 2- 4 cups of coffee a day, roughly 200 – 300 milligrams of caffeine. It would take around 6,000 milligrams of coffee to severely injure or kill, which is around 60 cups, a day.




  • jason

    Unless your “avid coffee drinkers” consumed roughly 60 cups of coffee a day, it is highly unlikely, in fact, almost scientifically impossible that their deaths were related to coffee consumption. It is possible the psychoactive affects that caffeine provides might’ve enhanced any existing mental or hormonal conditions, drinking coffee alone is relatively harmless, if not helpful. The “dropping dead” theory is probably due to the tendency of many “avid coffee fans” to drown their coffee in cream, sugar, and milk, which easily relates to heart conditions and restrictions. It is quite possible these coffee drinkers simply had heart troubles because they didn’t maintain their cardiovascular health. End Result? COFFEE DOESN’T KILL YOU. THE SUGAR, CREAM, AND MILK WILL.

  • jason

    However, I apologize if I offended or disrespected you in any way. I meant no harm, but simply get irritated when people hold the belief that coffee kills, or harms, when it is one of the most valuable and popular commodities in the world. If coffee was so deadly, don’t you think more people might have heard of it?

  • jason

    You e-vape caffeine juice? Sounds dangerous. I also like to live dangerously.

  • jason

    Theobromine poisoning is extremely rare, and it would take a large amount of coffee to get anywhere near. I

    n modern medicine, theobromine is used as a vasodilator (a blood vessel widener), a diuretic (urination aid), and heart stimulant.[1]

    Theobromine increases urine production. Because of this diuretic effect, and its ability to dilate blood vessels, theobromine has been used to treat high blood pressure.[21] The American Journal of Clinical Nutrition notes that historic use of theobromine as a treatment for other circulatory problems including arteriosclerosis, certain vascular diseases, angina pectoris, and hypertension should be considered in future studies.[22]

    Following its discovery in the late 19th century, theobromine was put to use by 1916, when it was recommended by the publication Principles of Medical Treatment as a treatment for edema (excessive liquid in parts of the body), syphilitic angina attacks, and degenerative angina.[23]

  • Farley Malorrus

    My friends that died never used cream or milk or sugar babies drink their coffee black or should I say all three Ray Howard and Mr Holmes. They all did have something in common though they were very stressed out they were very thin they ate very little other than coffee does the words of Coffee only diet just about which doesnt afford much nutrition and they all died suddenly of heart failure this article says four cups of coffee you say 60 like you’re some kind of expert maybe you should keep up your four cups of coffee if they have it and see what happens if you live long enough your right and if you die you have my sympathy. Coffee still has an unnatural effect on your adrenal glands and makes your adrenal glands pump adrenal all day long like you’re in danger to me that this doesn’t work sorry besides I get such terrible gas pains when I drink any caffeine at all if you look like you’re having a heart attack so in my book coffee sucks so go drink your coffee and enjoy whatever life you have left peace

  • Farley Malorrus

    If you drink coffee and you don’t realize it’s a drug and you’re just in denial. Like nicotine and cigarettes or alcohol or even opium in vicodin caffeine is quite addictive and it does speed up your heart rate pump adrenaline and effects you physiologically. It is definitely a drug and those people that drink Mountain Dew for example there’s like 10 cups of coffee with the caffeine in a mountain dew and some of these rage drinks like Red Bull and such. If you need something to speed up your day because you lack energy and you don’t use meth coke or white little white pills that are used to be called speed then Coffee would be your speed. I prefer to go through my life without having to be dependent on anything or addicted on anything hence the reason why I don’t smoke I don’t drink and I don’t use caffeine. Because of life to live a long natural life without having a monkey on my back for anything. My friends and relatives the drink coffee are like cigarette smokers looking for their necks stogie when you hang out with them it’s all about the coffee when they wake up in the morning it’s all about the coffee coffee coffee coffee they’re obsessed with it when there’s a funeral the first thing somebody wants to know what the way is where is the coffee pot at it makes me want to throw up. So if you drink coffee and you think it’s fun are good for you are cute or something you have to have to make your day go maybe you should try getting up giving up coffee for 5 days left your adrenal glands resume back to normal and you might find a natural energy that you have where you don’t even need the damn drug. But then again those of you that are in denial that love the stuff you’re addicted to the stuff you can’t live without it well you can lead a horse to water but you can’t make him drink do you all have my sympathy in the end when your heart runs out of time and beats and just stops. No offense but Coffee is illegal drug just like speed and it works and your body exactly like speed and those people that drink expresso some Starbucks and coffee in the morning – 3 cups for a pot of coffee just to get them self started are living there life and unnatural way and using Coffee as a drug to function and trust me when you get older and you run out of strength you run into stamina even Coffee doesn’t help keep you going good luck to you coffee drinkers and if you die an early death it’s your choice like getting you have my sympathy and that’s about it because I really couldn’t care less if you like coffee your problem not mine.

  • Farley Malorrus

    What cracks me up and is very ironic talking to cigarette smokers alcohol drinkers dope users are coffee drinkers it’s all the same. They all will tell you that are there in total denial of any harmful effects from what they’re doing to their bodies and that there’s nothing wrong with their habits. But I have seen 28 aunts and uncles and clean my parents are coffee drinkers and many of my friends with heart issues and it have died from cardiac arrest all coffee drinkers some major coffee drinkers that needed coffee all day long to survive until their hearts just wore out. I don’t need some stupid report from Mayo Clinic to tell me it’s because I’m a former coffee addict and before I gave it up I was getting such bad cramps from drinking the coffee that I felt like I was having a heart attack every single day where have to lay down take some gas medication and would finally would go away but it was frightening. And 67 years old it took a long time for that to kick in okay but when it did it frighten me especially after I saw my 3 friends from coffee drinking and all of my relatives died who are coffee addicts every single one of them. So all of you out there without the harmful effects of this pathetic ruse that the coffee industry puts on people making them think it’s either a good for them be funded drink or see no harmful side effects is about the biggest load of crap next to the dairy industry telling you that dairy products won’t clog your arteries. Life is all about free will choice that’s what it is it’s up to you to choose whatever you want to do with your life in a coffee is your foundation good luck with it but it’s doesn’t work for me because I know if I would have kept drinking coffee I would have probably died about 5 years ago. I’ve always been the guy to offer people with choice you want to smoke smoke you want to drink drink you want to drink your coffee go for it you want to do all three smoke drink and drink coffee fine good luck but if you die young. You get cancer or if you end up with emphysema or some other strange disease like cancer because of your terrible habits and because you don’t know how to feed your body something I don’t know called nutrition and instead of some crap like stuff that does nothing for you but kill you like cigarettes alcohol and caffeine then go ahead that’s what freewill choice is all about pick your poison kids and enjoy the rest of your life I’m done

  • Farley Malorrus

    Drink your coffee Jason ignore the facts have a good life pay no attention to the man behind the curtain just go ahead and drink all the coffee you can infect load up on it ok don’t listen to me I don’t know anything. Do whatever you think is right bro I don’t preach all I do is give people a choice I’ve seen a lot of coffee people coffee drinkers die terrible death mostly from heart related problems usually cardiac arrest or heart failure so go ahead can call the Coffee want I don’t take offense to your denial or to your post you think coffee is good for you good for you but one day if you develop a heart problem or need a heart bypass are you have a heart attack or stroke Hey Baby its Coffee related right? I mean if you can combine a stressful life with lack of sleep and then drink a ton of coffee you’re going to die the fact stress plus no sleep plus Coffee equals death do the math have a nice day

  • Farley Malorrus

    You need a really solid life insurance policy brother because one day when you drop dead from all that crap you might want to leave a few bucks to your heirs. What you don’t realize is that you’re like a piece of dynamite with the fuse lit and burning and one day it’s going to blow so go ahead and drink all that caffeine go for it over dose on it see what happens one day 41 is young I drink a ton of that bull bull s*** when I was your age to know a fact fact I was totally convinced it was good for me because it gave me a boost and I slept like a baby also see what happens if you make it to 50 or even 60 I doubt it good luck there soldier keep drinking that Joe you love it

  • Ted

    Hey Jason, We present both sides of the issue and caffeine does have negative properties. To ignore those isn’t wise either. We list all the benefits here.

  • Farley Malorrus

    You know it’s really pathetic it’s hanging out being with or living with a coffee drinker and alcohol user are a cigarette smoker that carries around three balls and chain, they can’t do anything without their coffee cigarettes and booze. So when you’re ready to get up and go you gotta wait for them to have their smoke their drink and their coffee to get anything done they got three monkeys on their back and they think it’s good for them it’s fun it’s the American Way before those of us that don’t drink and don’t smoke and don’t need coffee it’s boring it’s downright stupid and it’s obviously sitting there watching someone who is terribly addicted to commercialism you wouldn’t understand unless you gave up smoking drinking and coffee drinking and then you around somebody that can’t live without it oh I can’t do anything without my morning cup of coffee where’s my coffee I need my f****** Coffee b******* it’s all a load of crap it’s brainwashing it’s the coffee industry making you think you need something you don’t need making you think you can’t do anything in your day without drinking that crap give me a break okay all these coffee houses and Starbucks you know its weird they have all their customers addicted. I smoke a little weed but I don’t have to get stoned all day long or everyday or live by at RB chronically addicted to it I might take a puffer to once or twice before I go to sleep medical marijuana right but I’m not addicted to it like coffee addicts that can’t even get out of bed without a quick cup of coffee give me a break so lonely boring and stupid but it’s pathetic to watch somebody so addicted to something they really don’t need but if you think you need a cup of coffee to make your day work then go ahead and drink it that’s your choice frankly I did not and rather not be addicted to anything except maybe God that’s just the way I am good luck with your coffee habits its stupid and then there’s this guy bragging about how much caffeine and puts in his body all day long with Coffee and green tea and Eva caffeine talk about ridiculous Penny 41 years old may never even see 45 but he’s bragging about how much you can take while that guy’s life line is on a short leash but he won’t know until after he’s dead or even that but everybody to know someone know it because they’ll know what killed them the caffeine makes me sick people are addicted and they’re in denial about it I have friends to give up drugs and then they live on caffeine like you’re not addicted anymore yeah right give me a break you do coke me to speed and mouth all your life then you give it up for having triple cappuccinos all day long and you think you’re not addicted yeah lol you’re not addicted right you can’t freaking move or do anything in your day at all lets you have your stupid cappuccinos do the math people do the math they’re not interested in saving your life you’re interested in making a buck

  • Tracy F

    ? Apart from death I had every symptom from drinking coffee plus it was making me aggressive, I’m living proof, I now feel 110% healthier since giving up coffee over a year ago. Coffee should come with warning signs on all their jars and packagings stating all the side effects, I will never drink coffee again! (For the record I don’t drink tea). Water tastes great. ?

  • mmanotforlife

    You are a prime example of why academia and the medical industry are misguided. These symptoms the article lists have been experienced by thousands if not millions of people including myself. You use your concepts and ideological thinking to draw incorrect conclusions, but if you developed your higher mind like gut instinct and conscious awareness of your subconscious mind you would sense that coffee is fools gold for what everyone is after. And being vibrant and full of energy can be achieved and it all comes from within

  • mmanotforlife

    Jason the 60 cup of coffee stat is utterly ridiculous. Try drinking 40 cups of coffee a day wouldnt be long until you died even 25 cups

  • luckysingh

    I only drink 4 to 5 cups a day I’m having insomnia like symptoms what should I do?

Last Modified: November 9, 2017