Can Caffeine Cause Insomnia? (Will Caffeine Withdrawal?)
The effects of caffeine on sleep has been studied in great detail.
And it’s clear that, yes, caffeine can cause insomnia.
I’m going to summarize that research in this post, and along the way we’ll look at things like:
- How much caffeine per day increases your risk of insomnia?
- Does caffeine impact the quality of your sleep?
- How long does caffeine stay in your system?
- Caffeine content of different caffeinated drinks
- Can caffeine withdrawal make insomnia worse?
How Much Caffeine Per Day Causes Insomnia?
If you have just a sip of caffeine, you’re not going to get insomnia. There’s some sort of threshold where sleep issues start to show up.
One study has subjects consume 240 mg of caffeine per day and compared any health issues with a control group that didn’t have any caffeine.
What they found was that the caffeine consumers were (1):
- 1.4 times more likely to develop insomnia
- 1.3 times more likely to experience headaches
- 1.6 times more likely to experience heart palpitations
Another research team did a large study of the general population to see how the number of cups of coffee corresponded with sleep issues (2):
Individuals who consumed on average >3 cups of coffee had the highest incidence of chronic insomnia.
People who had 0, or 1-2 cups of coffee per day had the lowest risk of developing insomnia.
Because of the limitations of this study, we don’t know the size of these cups or type of coffee.
Summary1-2 smaller cups of coffee per day likely doesn’t have a significant impact on insomnia for most people (some people are more sensitive), but consuming an amount of caffeine close to 240 mg per day significantly raises the risk of insomnia.
How Long Does Caffeine Stay in Your System?
The time you drink caffeine also plays a role in sleep issues.
The more caffeine in your system when you’re trying to sleep, the harder it’s going to be.
The average caffeine half-life in healthy people is 5.7 hours (3). Some people will digest it a bit faster or slower than others.
Using this handy half-life calculator, we can see that it takes over a day for 100% of caffeine to get out of your system.
To get 75% of it through your system, it takes just under 12 hours. This amount will likely have some effect on your sleep, but it may be tolerable.
The tolerable amount will depend on the individual, but for many people that amount is close to 0.
SummaryIn short, there will be some caffeine left in your system on the day that you consume it. Consuming it as early as possible will minimize the amount left when you’re trying to sleep.
Does Caffeine Affect Sleep Quality?
One other interesting piece of research I came across shows that caffeine has a potential detrimental effect on your sleep quality (4):
Decaffeinated coffee had no effect. Regular coffee and caffeine caused rapid eye movement (REM) sleep to shift to the early part of the night and stages 3 and 4 sleep to shift to the later part.
Deep sleep (stage 4) is the most restorative stage of sleep. It’s where growth hormone is produced in the highest quantities, which is needed for cell repair. Additionally, memory formation and storage is one of the main processes that happens at this stage.
If you sleep 10 hours, then it’s not a big deal that deep sleep is pushed later.
But if you only sleep for 5-7 hours, you could be missing out on a large chunk of deep sleep, which decreases the quality of your sleep.
Caffeine Content of Different Caffeinated Drinks
The amount of caffeine in different drinks varies widely based on the drink and size.
You’re going to have to look up the amount in any caffeinated drinks that you have on a regular basis.
Here are a few drinks for reference:
- Black coffee (8 oz - 227 mL) - 96 mg of caffeine
- Coffee with espresso shot (20 oz - 568 mL) - 398 mg of caffeine
- Pepsi (20 oz - 568 mL) - 63 mg of caffeine
Here’s a more complete list of popular caffeinated drinks that you can buy.
Earlier, we saw that you probably want to aim for no more than 2 standard cups of coffee (~200 mg of caffeine) per day.
Some of the drinks on this list have more than that by themselves. An extra large coffee with an espresso shot can have up to 400 mg of caffeine - yikes.
Can Caffeine Withdrawal Cause Insomnia?
After learning what we have so far, many people who have sleep difficulties immediately stop consuming caffeine, or cut back significantly.
But you have to remember that caffeine is a drug, and cutting back or eliminating it once you’re used to it comes with withdrawal.
Ironically, one of the symptoms of caffeine withdrawal can be insomnia. Sleep issues often get worse before they get better (5).
How Much Caffeine Intake Leads to Withdrawal?
One team of researchers did a series of double-blind experiments to answer a bunch of related questions to this topic.
Here were there main findings (6):
- Caffeine withdrawal symptoms were seen in people who consumed as little as 100 mg of caffeine per day.
- The more caffeine someone was used to, the more severe the withdrawal was.
- For people used to consuming 300 mg of caffeine per day, symptoms only appeared when consumption was cut to under 100 mg per day. So it may be possible to taper down slowly and minimize symptoms.
- It takes as little as 3 days of caffeine exposure to experience symptoms after withdrawal.
Another research team found that people who suffer from anxiety or depression are more likely to experience withdrawal symptoms (7), although that’s partly explained by generally being in poorer health or taking other medication.
How Long Does Caffeine Withdrawal Last?
Note that the most common symptoms of caffeine withdrawal are headaches and fatigues. Insomnia is sometimes reported, but also not that common.
Symptoms usually go away within a week or two (8):
SummaryOnset of withdrawal symptoms typically occurs 12–24 h after abstinence, with peak intensity occurring at 20–51 h, and duration of withdrawal ranging between 2 days and 9 days.
Why Caffeine Withdrawal Can Cause Insomnia
It’s not fully understood why only some people get insomnia from caffeine withdrawal.
The most likely explanation (or at least part of it) is due to the effect of caffeine on cortisol.
In short, cortisol responses to caffeine are reduced (9). But having cortisol levels that are too high or too low can contribute to insomnia and other side effects (10).
SummaryIn unscientific terms, too much caffeine can mess up your body’s cortisol control, and until your body gets your cortisol levels back to normal, it can cause sleep issues.
Summary: Caffeine and Insomnia
Here are the main takeaways from all the research we’ve looked at:
- Yes, caffeine can cause insomnia. It's one of the biggest risk factors of insomnia
- Only 75% of caffeine is out of your system after about 12 hours
- If you must drink caffeine, drink less than 200 mg per day
- Caffeine withdrawal is a real thing and comes with several symptoms, which may include worse insomnia in the short term for some
- Caffeine withdrawal usually subsides within 1-2 weeks. Reducing the amount of caffeine consumed slowly may reduce symptoms
Many people drink caffeine because of their sleep difficulties in the first place, but this only makes them worse in the long term.
If you’re trying to improve your sleep, cutting out caffeine, or drastically reducing your intake should be one of the first things you do.
- A Study of Caffeine Consumption and Symptoms: Indigestion, Palpitations, Tremor, Headache and Insomnia
- Risk Factors for Incident Chronic Insomnia: A General Population Prospective Study
- Serum caffeine half-lives. Healthy subjects vs. patients having alcoholic hepatic disease
- Dose‐related sleep disturbances induced by coffee and caffeine
- Effects of caffeine withdrawal on nocturnal enuresis, insomnia, and behavior restraints.
- Caffeine Withdrawal: A Parametric Analysis of Caffeine Dosing Conditions
- Caffeine-Withdrawal Headache: A Clinical Profile
- A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features
- Caffeine Stimulation of Cortisol Secretion Across the Waking Hours in Relation to Caffeine Intake Levels
- Recurrent short sleep, chronic insomnia symptoms and salivary cortisol
Medical Disclaimer: The information on SnoozeUniversity.com is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.