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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  • Ted

    I’m not sure why your organization can’t recognize that caffeine is a drug and does come with certain risks. You write off all of these studies as “not conclusive” but any study that talks about caffeine benefits is taken as gospel. We present both sides of the issue and have just as many articles that discuss caffeine’s benefits. You can’t ignore all the negative research and only accept the positive. People should consider all of the facts and then consider what is best for them based on their particular health profile. A blanket endorsement of caffeine like you are offering isn’t very responsible on your part, but I guess your organization is highly motivated to keep people consuming caffeine because it is part of your livelihood.

  • Kayley

    I am allergic to caffeine I didn’t know that I was but if I eat or drink to much I have a very upset belly and grow up and I known my head get heavy everrytime I drink ice tea and I get a lot of gas from caffeine and I got dry skin around my neck resently and that how I knew I am allergic to caffeine and it sucks cause I love chocolate,ice tea and coffee

  • youguysareallstupid

    coffee isnt harmful at all. I have been drinking it for a while you guys r dumb

  • youguysareallstupid

    I seriously hate all of you there is no evidence behind any of these claims if I were to make a blog and say god exists you probably would all believe it. So sad, all of you.. A bunch of mindless animals

  • Wally Walton

    A more recent article published by Phd Dr. Yamak, showed that consuming over 3 cups of coffee a day could lead to hair loss with young males, and erectile dysfunction. Well, that settles it for me. Gonna quit cold turkey.

  • duh

    Yeah but you reading and commenting on stuff like this when you do like caffeine–that’s just logical. Let’s all read informative articles that could explain for other people why they’re having ailments and get dick hurt in the comment section!

    I don’t see how labeling how much caffeine is in things or letting people know potential harm affects your 4 cup brag.

  • John Sabia

    There is a great healthy alternative to Caffeine called Theobromine which is found in raw chocolate.

    check out Micacao.com for a healthy energy drink alternative.

  • medhead

    Soda has only 8mg of caffeine a can and coffee has between 100-200 mg…. so 8 cans of pop is nothing really…

  • Ryan Doyle

    All I can say is caffeine and nicotine are very similar. Both are stimulants. Both serve the same function in nature: to be released as poison to insects when they try to eat them.

    Also, the mainstream medical advice on cigarettes used to be moderation, not abstinence. Many even claimed, like they do with coffee now, that smoking had health benefits!

  • Gerry Keefe

    Too bad coffee can’t help you spell. That includes your name. Less coffee, more spellcheck bud.

  • Lovely OY

    whatever drugs you’re on you should stop – nobody hates everybody – that’s probably your drugs talking

  • Tommy Hass

    Smoking DOES have health benefits. It doesn’t matter though.

    Also, the idea that smoking tobacco is comparable to drinking coffee is ridiculous.

  • adam

    Consider all things with an open mind. Only then can you make an informed decision.

  • Wm

    Great post… I experienced all these effects. I would add that Caffeine gave me Irritable Bowel Syndrome too: a cycle of having diarrhoea for a few days followed by a few days difficulty passing. The IBS symptoms went away within 7 days of giving up coffee. I have no doubt that the IBS was caffeine related because I gave it up a previous year and had the same improvements.
    I have noticed that my vision is clearer and my skin looks better, all after only 10 days.

  • PineappleKat

    There are sources/evidence linked and mentioned through this whole article and many post have been cited. Maybe if you weren’t so lazy you would have looking into these sources and never commented. Grow a brain.

  • denlee

    Would you care to “enlighten” us regarding a spelling error in “youguysareallstupid” – appears you might have that problem, Gerry!

  • denlee

    My experience with caffeine: During formative years, did not drink caffeine, or Coke. Nor did I during my Army enlistment, neither during my 8 years in college.
    Began when my working career began, fair bit of time in an office environment – everyone had their morning coffee..
    Soon discovered that every Fall I would go through a significant bout of “Hay Fever”, which was totally new for me, and for which I usually had to take OTC meds. At some point I read that caffeine was a “constrictant”, which led me to wonder if there was a connection to the coffee, and the high intake of polligens during Fall (my assumption was that the constrictive nature of caffeine reduced normal synus drainage, which led to “pollen overload” . So, I weaned off coffee prior to “the hay fever season” one year – wala! no symptoms of hay fever whatsoever (had to ween down gradually, or suffer intense migraine headaches). So, for the rest of my years, until about the age of 65, I followed that routine – no caffeine during Fall – I liked coffee, and it’s stimulus, so always got back on it after the “pollen” season had ended. For some reason, for the past several years, I seem to have “outgrown” the problem, as I no longer do the seasonal withdrawal thingy, and no longer have a problem – go figure!

  • Jesse Dilport

    This article is about the negative health effects of consuming larger amounts (200mg+) of synthetic caffeine (i.e. caffeine from an unnatural source).

    This article is NOT about the negative health effects of drinking a couple cups of coffee a day.

  • Kara

    where can I find that article by Dr. Yamak?

  • ferdz

    yes it is true…all of them. but still hard to quit drinking coffee.

Last Modified: November 9, 2017