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How Long Does Caffeine Last? [Withdrawal & Effects on Sleep]

How Long Does Caffeine Last? [Withdrawal & Effects on Sleep]

Clark Clark
10 minute read

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Coffee is a daily ritual for many people out there who find it a delicious way to get that energy boost they need to start their day. 

But what makes us so dependent on caffeine, and how does it give us that boost we crave? In this article, we'll answer, "How long does caffeine last?"

(Don’t worry — we love coffee, too. It is possible to drink healthy coffee.)

What Is Caffeine?

Caffeine is a stimulant found in 60 different plants. 

You’re likely most well-acquainted with coffee plants. The coffee you’re drinking comes from coffee beans, or coffee plant seeds. Caffeine is often the preferred drink of choice in the morning for its positive effects: a kick of energy and alertness to start your day.

What contains caffeine? A cup of coffee isn’t the only available source of caffeine. You’ll find varying amounts of caffeine content in many different sources:

  • 8 ounces of brewed coffee: 95 mg
  • 8 ounces of instant coffee: 60 mg
  • 1 shot (1.5 ounces) of espresso: 64 mg
  • 8 ounces of black tea: 47 mg
  • 8 ounces of green tea: 28 mg
  • 8 ounces of decaffeinated coffee or tea: 2-4 mg
  • 12 ounces of regular cola: 34 mg
  • 12 ounces of diet cola: 46 mg
  • 12 ounces of Mountain Dew and similar soft drinks: 54 mg
  • 1 ounce of dark chocolate: 24 mg
  • 8 ounces of most energy drinks: 85 mg

A quick note on energy drinks: Most cans come in 12 ounces or more, so keep that in mind if you’re trying to limit your caffeine intake. 

How long does caffeine last in the human body?

For most people, that immediate jolt of caffeine comes within just 10-15 minutes of consuming it. After 45 minutes, you’re likely enjoying peak levels of caffeine consumption. 6 hours after you’ve had caffeine, about half of it is still in your body.

How our bodies process caffeine can vary from person to person, from your height to your weight, to how much caffeine you’ve consumed, to how dependent you’ve become on caffeine as your energy source. 

Can caffeine affect you 12 hours later?At about 5-6 hours, nearly half of your dose of caffeine has been metabolized by your body. That’s caffeine’s “half-life” and why you won’t want to have any caffeine close to bedtime. A good rule of thumb is to avoid it about 8 hours before you’re ready to hit the hay.

That’s just an average, though, and your caffeine sensitivity can certainly come into play here. Those who generally have less caffeine will likely have a lower caffeine tolerance for those additional espresso shots and may have trouble sleeping that night as a result.

Is caffeine addictive? As a naturally occurring stimulant, caffeine can become addictive as you develop a dependency on it. Caffeine does, after all, give you those warm and fuzzies on top of a boost in alertness, feelings that most caffeine users likely enjoy.

But there’s some disagreement among researchers as to whether caffeine can go beyond dependency and into addiction. If you ask the American Psychiatric Association (APA), they’ll go far enough to recognize caffeine withdrawal symptoms as a clinical condition without calling caffeine use itself an addiction.

The World Health Organization (WHO), though, has recognized caffeine dependence in some people as a clinical disorder.

Despite the benefits of caffeine, it’s then essential to understand that too much caffeine isn’t always a good thing, despite how you feel after that coffee fix.

Caffeine’s Effect on the Body

Caffeine’s energy-boosting properties are caused by where it goes once it’s past your lips. 

The caffeine hits your bloodstream, stimulating your central nervous system into a more alert state. Those who are used to regular caffeine consumption may not feel the effects as quickly as those who limit their caffeine intake. 

Caffeine tolerance is a thing, and you may find that the more caffeine you consume, the more you’ll need for those same positive effects you were enjoying.

How long caffeine lasts really depends on your tolerance and a few other factors we’ve mentioned: your body type (including heights and weight), how much caffeine you’ve taken in, and your sensitivity to caffeine. 

7 Health Benefits of Caffeine

Caffeine’s benefits make it a safe option in moderation if you’re feeling less than alert. The health benefits of caffeine include:

  • Improved focus, concentration, and alertness
  • Improved energy levels
  • Boosts in memory and reaction times
  • Potential link to dementia prevention
  • Metabolic boost and weight loss support
  • Better physical performance
  • Improved mood and quality of life.

If you like to drink coffee or fancy a latte from time to time, there are several additional benefits of coffee, too. These range from lowering your cancer risk to balancing your blood sugar to the prevention of chronic diseases

Believe it or not, that cup of coffee could actually be increasing your life span!

Symptoms of Too Much Caffeine

You can have too much of a good thing. If that morning cup turns into a pot of coffee, you may experience symptoms of too much caffeine.

How much caffeine is too much caffeine?Generally, the Food and Drug Administration (FDA) recommends that about 400 mg of caffeine consumption per day is considered safe if you’re healthy. 

Pregnant or breastfeeding women should cut back to 200 mg of caffeine per day or less, the typical amount most Americans consume in a day. (That’s about two 8 ounce cups of coffee, by the way.)

How long does it take for 200 mg of caffeine to wear off?You’ll feel the effects oftwo cups of brewed coffee, which is just about 200 mg of caffeine, for about 5-6 hours. 

So how do you know if you’ve had too much caffeine from those caffeinated drinks?

Symptoms of too much caffeine include:

  • Headaches
  • The “jitters,” or general feelings of shakiness
  • Disturbed sleep patterns, even insomnia
  • High blood pressure
  • Stomachaches or other intestinal irregularities
  • Irritability
  • Increased heart rate or irregular heartbeat.

Can you flush caffeine out of your system?Unfortunately, there’s no way to truly flush caffeine from your system.

Besides waiting out the effects of too much caffeine, you can help yourself feel a little better by drinking more water. Caffeine is a mild diuretic that can force you to make more trips to the bathroom. Water will hydrate you and make any resulting headaches easier to manage.

Some people trying to get back to normal after too much caffeine report light exercise helps, too. What you don’t want to do is have more caffeine — it’ll just prolong the inevitable withdrawal.

Symptoms of Caffeine Withdrawal

What is caffeine withdrawal? If you cut caffeine out of your diet entirely and abruptly, you may experience caffeine withdrawal. It is, after all, a stimulant, and its withdrawal symptoms have been officially recognized in the Diagnostic and Statistical Manual (DSM-5).

Looking to cut back on your caffeine intake? You may experience some symptoms of caffeine withdrawal like: 

  • Mood changes (crankiness, anxiety, depressive symptoms)
  • Loss of focus and concentration
  • Low energy
  • Headaches
  • Tiredness and general fatigue
  • Nausea or an upset stomach.

How do you get caffeine to wear off?Caffeine withdrawal symptoms usually wear off within a few days of abstaining from caffeine. 

If you’re a heavy coffee drinker, your caffeine withdrawal symptoms may be more severe. It may make more sense to cut back gradually if you’re looking to reduce your caffeine intake or even going decaf for a while.

How to Avoid Too Much Caffeine

You know where the caffeine is lurking now. If you’re looking to avoid too much caffeine, you’ll need to look at the areas where you’re consuming it and cut back.

Switching to decaf is an option, or using those herbal tea leaves in the pantry to mix things up if you’re trying to limit your daily coffee habit. 

If you just want to make healthier choices with your caffeine intake, consider whether you need the energy drinks at all. They just don’t have the same benefits that a cup of coffee does, and they’re often loaded with tons of sugar.

Who Should Avoid Caffeine?

If you’re not sure whether you should have caffeine or are worried about your caffeine levels, it’s always best to talk to your doctor about limiting caffeine or cutting it altogether.

We’ve already mentioned that pregnant women or women who are breastfeeding should be limiting their caffeine intake to a maximum of 200 mg per day, if they’re drinking any caffeine (depending on their doctor’s orders). 

Limiting caffeine may also be beneficial for those who have:

  • Medications that can interact with caffeine
  • High blood pressure
  • Rapid heart rate 
  • Anxiety
  • Gastroesophageal reflux disease, or GERD
  • Sleep disorders.

A quick note on those suffering from GERD, IBS, even gastric ulcers: Low acid coffee, like ours here at Golden Ratio, can allow you to have your coffee and drink it, too. 

Traditional coffee can be tough on tummies, exacerbating intestinal issues and giving you that energy boost with a side of painful side effects. Some of that is because of the acid in your brewed coffee. Ours has 5 times less acidity than that dark roast you’ve been sipping.

Is there caffeine in medicine?

Some medications contain caffeine, so you must read labels carefully if you’re looking to cut back. Keep an eye out for painkillers, migraine, and headache medications like Excedrin and diet pills, as those are the most likely medications to contain caffeine. 

Herbal supplements may also contain caffeine. Guarana, found in both extract and powder form as a popular dietary supplement, has more caffeine than any other plant out there. 

Consider Golden Ratio Coffee

Sometimes people cut back on coffee not to limit their caffeine, but because something about that coffee just isn’t agreeing with them. It could be the acid in your homebrew that’s making you feel some distress.

Golden Ratio coffee is a great example of a lighter roast, low acid coffee. It’s gentler on your stomach and a way to make coffee an even healthier choice if you’re worried that it isn’t the caffeine causing you problems.


  1. Caffeine Use Disorder: A Comprehensive Review and Research Agenda
  2. Biochemical mechanism of caffeine tolerance
  3. Caffeine intake and dementia: systematic review and meta-analysis
  4. Coffee and its consumption: benefits and risks
  5. Coffee and health: a review of recent human research
  6. Coffee consumption and risk of total cardiovascular mortality among patients with type 2 diabetes
  7. Spilling the Beans: How Much Caffeine is Too Much?
  8. Caffeine Use Disorder: A Review of the Evidence and Future Implications

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