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.

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  • Ted

    You probably should cut back, or not consume any caffeine after 2 pm.

  • truth

    No. Because it’s a big business. You’re out of your league here in being ignorant to coffee’s effects. It causes unnatural reactions in your body and the biochemistry and metabolic responses have both short term effects and long term. From blood pressure, to tension in the bones, to absurd cortisol risings and unnatural adrenal gland responses that should only be happening in fight/flight situations – it’s not healthy. If you’re building an attachment to something and ‘need it’ there’s also an addiction that’s occurring in the mind. I suggest reading Caffeine Blues because if you were informed you wouldn’t be shocked that coffee harms. You’re really behind, Jason.

  • Meresa

    Totally agree witbh you?

  • Joe Blogs

    Well said too much of these so called scientific people that it is actually in their interest to say how great Caffeine drinks are, and they really couldn’t care about anyone. However trying to find out what the world wide Ussage figures are is not easy there are some old figures around showing that it is in Big business interest to sell Cafeine, no matter what it is doing to most people in many ways.

  • Maddie

    From what i’ve experienced, caffeine is okay in moderation. 100mg of caffeine a couple times a week is not going to kill you. I haven’t experienced any of these extreme symptoms, but then again I don’t use extreme amounts of caffeine.

  • Erin

    I noticed a huge difference in my body when I went from 2 cups of coffee per day to 1 cup. I feel so much better and my blood pressure is lower. The first three days I woke up with a headache coming down from the caffeine.

  • Erin

    Cut back to 1 cup per day, you will feel so much better, I do.

  • KaaaMeeHaaMeHaaaaa!!

    Damn….is caffeine really that dangerous? Now I gotta cut down! I work night shifts so I drink 2 large cups! I drink it slow cause I like to enjoy the taste, but regardless, damn! I think I am murdering myself….

  • Caryl

    My husband drinks 3 to 4 cups of coffee a day and then one diet soda after another all day up until he goes to bed. No water and has very high stressful career. He is 60. I’m very worried and he is starting to have tremors at night when he sleeps. Sort of jerks around a lot . Just in the last few days. This last week has been extremely stressful. What is happening??

  • Yuki

    What the hell is this??? I read somewhere that drinking coffee 2 to 3 cups a day
    can help you lose weight.
    So I tried it I started drinking 2 to 3 cups a day and I did lose a few kgs. I did not get any of the symptoms.
    But IF anyone tries this make sure you drink a lot of water too.
    Coffee boosts your metabolism

  • Robert Baker

    1. Caffeine can cause tinnitus (ringing of the ears). Early on it’s reversible but at some point it isn’t and can cause hearing loss as we age.
    2. Caffeine is one of the causes of gray hair along with other factors such as genetics, age.. 3. Caffeine is a common cause of sleep disorders and often the technique of no caffeine after a certain time of day doesn’t work, as the metabolism of caffeine slows down as we age. Even though caffeine serves to wake people up in the morning, the sleep disorder results in a vicious cycle of poor sleep increasing the need for more caffeine. 4. Caffeine can frequently cause muscle cramps, often in the legs and at night when a person lies down. 5. Caffeine can cause panic disorder, anxiety disorder. 6. Caffeine is extremely correlated with manic depressive illness and improvements and even resolutions have occurred with complete cessation.
    Caffeine often works as a laxative and this accounts for some of the favorable effects that have been reported in studies. However the same positive effects result from a healthy high fiber diet.
    Coffee is the main source of caffeine but some people are sensitive to the smaller amounts of caffeine in many sodas, and some people drink a liter or two of caffeinated soda a day. (diet soda has caffeine also, unless it is no caffeine soda.)
    Caffeine becomes an emotional issue and this post may lead to emotional responses from deniers.

  • Andrew

    Tea and coffee produce an immediate effect. Under the influence of these poisons the nervous system is excited; and in some cases, for the time being, the intellect seems to be invigorated, the imagination more vivid. Because these stimulants produce such agreeable results, many conclude that they really need them; but there is always a reaction. The nervous system has borrowed power from its future resources for present use, and all this temporary invigoration is followed by a corresponding depression. The suddenness of the relief obtained from tea and coffee is an evidence that what seems to be strength is only nervous excitement, and consequently must be an injury to the system. {CG 403.2}

  • Andrew

    The use of tea and coffee is also injurious to the system. To a certain extent, tea produces intoxication. It enters into the circulation and gradually impairs the energy of body and mind. It stimulates, excites, and quickens the motion of the living machinery, forcing it to unnatural action, and thus gives the tea drinker the impression that it is doing him great service, imparting to him strength. This is a mistake. Tea draws upon the strength of the nerves, and leaves them greatly weakened. When its influence is gone and the increased action caused by its use is abated, then what is the result? Languor and debility corresponding to the artificial vivacity the tea imparted. {CH 87.1}

  • Robert

    Make it 6 cups

  • Robert

    I agree with Jason. Replace the word “caffeine” here with any of a thousand other every day substances, and you’ll get almost the same list, or worse. Use caffeine, like all other things, in moderation. The difference between excess and moderation of just about anything is the only difference between it being safe, or poison. In other words, “the poison is in the dose” as they say.

  • anonyous1212578

    You guys “adrenal fatigue” is a total lie. I drink like 8 cans of soda a day and whenever I get in a fight I can gurantee you my adrenaline is stronger than most people’s because my body pumps all of it out at once, it is called blacking out(like hulking out).

  • Robert

    Did you really need to hear the answer to that ??

  • Gerson

    I don’t need to wait the positive effect of caffeine in my body before I will stop.health awareness. I love myself and I’m looking after myself.I experienced vomiting,insomnia, nervous, anxiety and indigestion when I am drinking coffee and tea 2-3x a day but now I completely stop.I just drink pure warm water all day and all my problem was gone very quickly specially in my loose bowel movement.thanks to the hot water and the kettle…

  • Robert

    I see many posts suggesting that caffeine should labeled and /or controlled in some way. Bottom line – I and millions of others drink up to 4 cups a day without any of the ill effects listed. You don’t like caffeine? Don’t drink it ! Leave the rest of us alone.

  • You’re exactly right that an association is far from causation. These studies neither put forth conclusive evidence, nor do they debunk the body of science that finds caffeine is safe. Quite to the contrary, there are a growing number of studies that show caffeine and coffee actually have health benefits, when consumed in moderation. Also, readers might be interested to know that the 2015–2020 Dietary Guidelines for Americans actually advocate moderate coffee intake and reference research that establishes its positive effects. In other words, people should let the facts drive their decisions, rather than alarmist and inaccurate articles such as this one.

Last Modified: November 9, 2017