The Effects of Caffeine: Both Positive and Negative

Caffeine: the legal drug used by adolescents to adults all over the world every day. In fact, more than 90% of US adults consume caffeine each day. It’s become the daily go-to stimulant to increase wakefulness, alleviate fatigue, and improve focus. Depending upon how much you consume, the effects of caffeine can be either good or bad.

The Effects of Caffeine: Both Positive and Negative 

Effects of Caffeine infographicHow much caffeine should you consume in a day? 
Like any stimulant, caffeine should be used in moderation. To dispel the misleading information around caffeine, we’re going to answer all your caffeine-related questions. We’ll explain how much you should consume each day and how you can use it for your benefit.


According to The Food and Drug Administration (FDA) up to 400mg of caffeine, a day appears to be safe for most healthy adults. That's the amount of caffeine you’ll get in four cups of coffee or 10 cans of Coca-Cola.

Children and pregnant women should consume much less than this. And toddlers and young children shouldn’t consume caffeine at all. 

Take a look at the amount of caffeine found in some of the most common beverages:

  • One 8-ounce cup of coffee: 95 to 200 mg
  • One 12-ounce can of soda: 35 to 45 mg
  • One 8-ounce cup of tea: 14 to 60 mg

A misconception of decaf coffee is that it’s caffeine-free. However, an 8-ounce cup of decaf coffee contains about 7 mg of caffeine. Caffeine-free soft drinks, on the other hand, contain zero caffeine.

What are the negative effects of caffeine?

shot of espresso

Caffeine has both positive and negative side-effects. Consuming more than 500-600 mg of caffeine a day can lead to insomnia, nervousness, restlessness, irritability, an upset stomach, a fast heartbeat, and even muscle tremors.

As previously noted, caffeine can be harmful for pregnant women. A report by Medical News Today suggests that consuming 300 mg of caffeine a day during pregnancy may increase the risk of low birth weight babies.

The other potential negative side effects of caffeine:

- Depression
- Increased blood sugar
- Problems during pregnancy
- Infertility
- Problems breastfeeding
- Gout
- Bladder problems
- Insomnia
- Headaches
- Hot flashes 
- Increase feelings of agitation.
- Fast or uneven heartbeat
- High blood pressure
- Dependency
- Irritability
- Heartburn
- Muscle tremors
- Caffeine can also lead to an increased amount of stomach acid, potentially causing an upset stomach or heartburn. 

    What are the positive side effects of caffeine?

    Elemental coffee tumblers

    Coffee does present a few possible negative side effects, however, it also provides many benefits:
    - Weight loss
    - Alertness
    - Improved athletic performance
    - Improved cognitive function
    - Reduced risk for Alzheimer's and Parkinson's disease
    - Improved memory
    - Improved liver function
    - Can help with eyelid spasm
    - Protects eyes against cataracts
    - May guard against skin cancer
    - Prevents kidney stones
    - Reduced risk of several cancers: Mouth, throat, and other cancers
    - Reduced risk of stroke
    - Lowered risk of type 2 diabetes

      How long does caffeine affect the body?

      caffeinated soda

      Caffeine can be consumed through beverages, food, or medicine. However it’s consumed, the blood and body tissues absorb caffeine within around 45 minutes. It reaches the peak level in the blood within 1 hour and remains there for 4 to 6 hours.

      But according to research done by the University of Michigan Health Service, you can begin to feel the effects of caffeine as quickly as 15 minutes after consumption lasting up to 6 hours.

      How do you detox from caffeine?

      caffeinated tea

      If you’re tired of getting headaches every time you miss your daily dose of caffeine, it might be time for a detox. Or maybe you just want to break the “hold” of caffeine.

      Thankfully, unlike most stimulants, the symptoms of withdrawal are short lived. When you suddenly stop drinking coffee you may experience symptoms such as headaches as soon as 12 hours after quitting. The severity of symptoms may increase after 20 to 48 hours before disappearing. But usually, your symptoms will completely subside within 72 hours. 

      If you want to avoid the symptoms of withdrawal, try to gradually reduce your caffeine intake over several days. If you’re a 4-cup per day drinker, try cutting back to 2 for a day or two. Then switch to green tea for a couple of days. Slowly removing the amount of caffeine you consume over a period of time will prevent headaches and any other symptoms associated with withdrawal.


      Caffeine is a great way to help you increase wakefulness, alleviate fatigue, and improve focus. Like any stimulant, too much can lead to adverse effects. Consume no more than 400mg of caffeine a day and you’ll be able to see the positive side effects without the negative.


      1 thought on “The Effects of Caffeine: Both Positive and Negative

      Brian W M

      I have an under active thyroid, and have taken thyroxine for 25 years or so (175 microgames current dosage ) I stopped caffeine in take for 4 days and the result was very similar to the thyroid symptoms, tiredness caused irritation and aggression, could hardly get out of my chair but didn’t realise the effect of decaffeinated Tea and Coffee, were the reasons behind these debilitating symptom 15 minutes after having a very strong coffee, I had a work out which included Squats and sit ups, my age is 68 but prior to the coffee may well have been like 98, hope I feel like this in the morning, any comments greatly received.

      April 8, 2021 at 09:35am

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