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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  • jameskatt


  • Jebson

    In the long run, caffeine seems to protect the prostate gland from cancer, but DO NOT drink coffee when suffering from an enlarged or inflamed prostate.

  • Future Blogger

    Good article. I have a critical view of how the caffeine in drinks contribute to early demise as well. Check it out at kmike772.wordpress.com.

  • daniel williams

    energy drinks and alot of caffeine make me feel dizzy and in pain

  • Butch

    Thanks Jenson about the prostate info! Great stuff!

  • Bob Huddleston

    The Caffeine Blues by biochemist Stephen Cherniske fully discusses the ins and outs of caffeine and includes peer reviewed medical journal references.

  • Robert Dell

    You know, it looks like it’s all either common sense or OTHER causes. Everybody knows that caffeine causes you to wake up so drinking it before sleeping is common sense that you may not sleep very well. linked to early death? do the research again and THIS time exclude those that have other reasons to die early such as exclude the couch potatoes, and smokers. may as well exclude habitual drug users and alcohol drinkers as well.

    I’m surprised they don’t say stuff about teeth discoloration or other problems and that’s the cause of the drink not the caffeine.

    I challenge “CaffeineInformer” to provide REAL accurate information instead of hearsay and comparisons of apples to rock salt. The only way I’ll accept that somebody died of caffeine is if it says so on the death certificate. that or they were in such a hurry to get their fix that they ran across the road and got hit by a car. in that case it’s an automobile accident not death by caffeine.

    by the way, what ever happened to “i before e except after c or when sounded like a as in neighbor and weigh” in the spelling of caffeine?

    [energy drinks and a lot of caffeine make me feel dizzy and in pain]

    just like the running doctor gag “then don’t do that”

    by the way again, be careful about looking for “caffeine free” tea. Tea has tannic acid NOT caffeine by nature and the tannic acid has similar effects of caffeine the caffeine free in tea stuff is just an advertising ploy in order to get you to buy their stuff. people without any problems at all with caffeine will even buy that because of the scare tactics. In fact, this site itself is just another scare tactic. You can tell by looking at the wording of the warnings and trying to pass frivolus informatio off as certified and correct information.

    compare apples to apples and you WILL find out that caffeine has no ill effects at all. somebody allergic to caffeine will react badly to it just like somebody allergic to peanuts or bee stings will react badly to those items.

    Robert Dell.

  • Ted

    Hi Robert, thanks for your feedback. We have several articles that discuss the benefits of coffee and caffeine as well. We try to present both sides of the issue and encourage discussion concerning the in’s and out’s of caffeine.

  • Robert Dell

    common sense there as well. energy drinks aren’t worth the damage they put your body through and it’s NOT the caffeine that does it. One way to lower the damage is to consume a lot of complex starches and proteins when you consume them and your body will have something to break down when they sense the rapid increase of caloric input but that will also lower the energy effect on you because the energy they release will be partly taken up digesting the food you just ate. just think about it next time. you want a LOT of energy then take cocaine not energy drinks and THAT’s only a temporary solution. NOBODY should need the extra energy that bad. wait until a cup of coffee takes effect, maybe add granulated CANE sugar (not beet sugar) and whole milk (the fat content is necessary) and your body will have an instant small increase of energy and it will slowly go up as each part of the coffee is digested. remember to take account allergies in your decisions on what to drink and don’t complain to me if you are allergic to caffeine and drink energy drinks then have severe allergic reactions to them.

    if you are allergic to caffeine then use tea not coffee. the tannic acid in tea does the same job as caffeine without the allergic reactions those who are sensitive to caffeine get. what *I* want to know is more information on this from Daniel. Did he read the package? Did the doctor say he was allergic to caffeine? was this before or after his reaction to the energy drink? was he diagnosed with acid reflux or something similar? was he taking medications for that?

    You can see, there are a LOT of circumstances that can cause you to have bad reactions to caffeine and it wasn’t the caffeine but the other circumstances that caused the problem and it was posted in a way to deliberately badmouth caffeine.

  • One of them too

    Jebson if you are still linked to this – can you provide any links to more info? Thanks!

  • zzzz

    keywords are “can” “may” “linked” “could”

  • Rick

    Your never going to get the “hard” facts on caffeine because it is consumed in great quantities by the public. I think last time I heard it was 90% of the population that consumes it regularly. My mind would tell me that its negative effects would be related to those of cocaine, amphetamine, or other related stimulates. I know its stimulating properties are far less then the other ones I just mentioned so the health effects should also be far less but in the same categories. Its like asking what the negative health effects are of fluoride and all your going to get is overdoes information. My main concern is the long term effects of caffeine, fluoride, and other chemical we are consuming on regular. The reason we consume fluoride is because we over consume food to produce profit. The over consumption of food makes us over tired and rots our teeth. This whole cycle requires us to stimulate our bodies with caffeine which means spend more money. The key to all this is how much money we spend and not our health, thank for reading.

  • Ted

    I hear you, but caffeine is one drug that we do have a lot of long-tern data on since it has been used for centuries as well as it being one of the most researched drug on the planet.

  • Bob

    Exact science is not an exact science

  • Karen Quartzstone

    Ted you silly goose.. what’s going on with caffeine is similar to what went on with cigarettes. same coverup, only now we have the internet and more books published so if you get your head out of your ass you can actually avoid the propaganda and see the truth that is out there about caffeine

  • Karen Quartzstone

    they fluoridate the water (with toxic chemical byproduct from industries such as the uranium and fertilizer industry, go ahead and check the EPA website where it’s openly admitted) because they are poisoning us, and because otherwise they would have to pay exorbitant amounts of money to dispose of the fluoride, which was once illegal to dispose of in nature because it’s That Toxic. leaked video of the fluoridation process also shows how toxic it is, But Anyways! That’s not even the point, the point is, that caffeine actually IS in the same family of drugs you mention, it’s related to cocaine and to morphine, and really caffeine is a pesticide produced by plants, literally a poison.. Caffeine destroys the beneficial bacteria in our gut, possibly up to a third of it in one go, which is staggering.. It also harms our digestive system in general, our nervous system, and our endocrine system. It doesn’t give us energy, it stimulates the adrenal glands and causes them to overwork, and that takes a toll, it doesn’t just return to normal at the end of the day or at the bottom of the cup of coffee or tea or soda or whichever poison.. Well Rick, you’re on the right track but there were holes in your research, especially regarding fluoridation which is basically pure evil.. so good effort, hope this helps to create a bigger picture. sorry if I sound rude, I’m very tired of all the bullshit and people being mislead or completely ignorant and I just want the truth to be heralded as the truth with as little nonsense as possible. bless you.

  • Karen Quartzstone

    I love that book Bob, it taught me a lot though I’ve not got an eyesore from rolling them so much when people fail to know any of the important information that’s presented in that book and available for dissemination all over the internet and other resources

  • Arhas Coffee

    Most articles coffee only contains positive and negative effects. In my article, I formulate detailed ways to distinguish how the positive effects of coffee and how the negative effects of coffee.

    Coffee is the energy surged . Coffee caffeine beneficial to the body as the brain and nerve stimulant and improve performance and concentration. Then the reaction of the body to feel warm and light / relaxed. But caffeine has added additional scent (essence) will be cafestol. Cafestol is a chemical compound that can increase cholesterol levels in the body. So we have to wisely choose caffeinated coffee good for the body. How to differentiate coffee bean / coffee powder (without essence) conducted oral / mouth without brewed. Take a little coffee entered the mouth, the result still feel the taste of coffee, savory bitterness, not swallowed rough. For smokers smoke so lightly. Conversely coffee bean / coffee powder mixed with artificial scent (essence), the result is very bitter, not feel the taste of coffee, swallowed rough. For smokers do not benefit. The conclusion by knowing the guidelines of natural coffee drink in the stomach will feel safe and secure for blood pressure, do not make trouble sleeping, not addicted, emotionally stable.

  • Johnny Laser
  • Ted

    Yes and we also added that to our growing list here a few weeks ago after it happened. https://www.caffeineinformer.com/a-real-life-death-by-caffeine

Last Modified: November 9, 2017