How Long Does It Take for Caffeine to Kick in and Wear Off?
We asked dietitians what you need to know about your cup of joe consumption.
By Karla Walsh•
Just like each of us tackles challenging runs, rides, and strength sessions at different rates, no two humans are alike in how their systems handle caffeine. So if you’re wondering how long it takes for caffeine to kick in and wear off, the answer is a very unsatisfying “it depends.”
That said, there are some general time ranges to consider—plus a lot of other helpful guidance to keep in mind when consuming caffeine, which is “the most commonly consumed central nervous system stimulant,” according to Lauren Harris-Pincus, RDN, a registered dietitian nutritionist, founder of Nutrition Starring YOU, and author of The Everything Easy Pre-Diabetes Cookbook.
Read on to learn how to time your caffeine consumption to make the most of the boost and steer clear of the buzz come bedtime.
How Caffeine Impacts Your Body
In short, caffeine can influence our mood, alertness, brain power, and even our athletic performance. Sometimes, it can also have some not-so-great effects, like needing to use the restroom more or feeling jittery.
“Caffeine is readily absorbed by the stomach and small intestine, the lining of the mouth, and even the lungs,” says Frances Largeman-Roth, RDN, a Dobbs Ferry, New York-based registered dietitian nutritionist and author of Everyday Snack Tray. This central nervous system stimulant “gets into the bloodstream quickly and interacts with all the cells in our body, including our brain,” she explains.
Caffeine is broken down in the liver, and as it’s metabolized, it binds to adenosine receptors found in the brain, heart, spinal cord, and autonomic nervous system, adds Mary Stewart, RD, a registered dietitian and the founder of Cultivate Nutrition in Dallas.
In the brain, these adenosine receptors regulate the release of neurotransmitters and are key in regulating cognition, memory, sleep, learning, and arousal, explains a May 2021 study in the journal Cureus.
As caffeine hugs those adenosine receptors, “it impacts the release of neurotransmitters such as norepinephrine, dopamine, acetylcholine, serotonin, glutamate, and gamma-aminobutyric acid (GABA),” Stewart explains. “These neurotransmitters alter mood, memory, alertness, cognitive function, and may positively impact athletic performance.”
Some other less-discussed downstream effects of caffeine consumption include:
You may feel more chipper. For many, caffeine acts as a mood-booster, Largeman-Roth says.
How Much Caffeine Is OK?
If you’re an adult without any preexisting conditions, the Food & Drug Administration (FDA) says it’s A-OK to consume up to 400 milligrams of caffeine per day. For context, here’s how much caffeine the most popular sources deliver, according to the FDA:
12-ounce can of soda: 30–40 milligrams
8-ounce cup of green or black tea: 30–50 milligrams
8-ounce cup of coffee: 80–100 milligrams
1 ounce of chocolate: 12 milligrams
8-fluid-ounce energy drink: 40–250 milligrams
Harris-Pincus says that anyone in the following groups should avoid consuming caffeine, or should definitely talk to their doctor before consuming it to determine how much is advisable:
People with high blood pressure
People who are pregnant or breastfeeding
People with heart arrhythmias
People with gastroesophageal reflux
People who have migraines
People who have sleep disorders
People taking certain medications who aren’t sure how they might interact with caffeine
Teens and kids
“If you notice symptoms that may be caused by a caffeine sensitivity, like headache, jitters, anxiousness, racing heartbeat, or insomnia, it’s important to find the right threshold to avoid these symptoms,” Stewart says.
How Long Does It Take for Caffeine to Kick In?
The degree and pace of caffeine’s effects varies based on a number of unique factors, Stewart says. But as a general rule, “caffeine starts working in as quickly as five minutes,” Largeman-Roth says, with effects typically hitting their peak starting about 45–60 minutes after consumption.
Of course, when exactly your biggest caffeine boost hits largely depends on your genetics, Harris-Pincus clarifies, as well as how the caffeine gets into your system and how many milligrams are hiding in that caffeine source. For instance, drinking a cup of coffee tends to work faster than eating caffeine in food form, which requires a more complicated digestion process.
Can You Drink Caffeine Before a Workout?
As long as you don’t notice any adverse effects from caffeine (such as digestive issues, sleep issues, increased nervousness, or anxiety), go for it! You might even feel like you have an extra boost, or that difficult workouts feel a bit less challenging. “While caffeine doesn’t actually give you extra energy to work out, it does make hard workouts feel easier,” Largeman-Roth explains.
Consuming coffee before a workout (or downing other forms of caffeine your body tolerates well) may increase alertness and tame your perception of pain and perceived exertion, all of which may be helpful if you’re trying to level up your sweat session.
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How Long Does It Take for Caffeine to Wear Off?
Generally, “caffeine is completely absorbed within one hour, and effects can last from four to six hours,” Harris-Pincus says. That said, caffeine will stay in your body longer than you’re likely aware.
On average, the half-life of caffeine is two-and-a-half to five hours. Half-life refers to how much time it takes for the amount of a substance to fall to half of its original amount. In practical terms, that means if you enjoy a cup of coffee that has 100 milligrams of caffeine at 7 AM, there will still be 50 milligrams of caffeine dancing around in your system until sometime between 9:30 AM to noon.
“This range is due to a variety of factors and based on how someone metabolizes caffeine, including genetics, of course, as well as body size, physical activity levels, smoking status, and certain medications, like oral contraceptives taken at the same time as caffeine consumption,” Stewart says.
As Stewart touches on above, how long it takes caffeine to wear off is largely impacted by genetics. It ties back to a gene called “CYP1A2,” which dictates the rate at which your body processes caffeine. This is why some people feel their morning coffee until dinnertime, while others can down an espresso after dinner with no ill effects—and it’s why there’s no single universal answer to how long it takes caffeine to wear off.
So, What Time Should You Stop Having Caffeine?
Since caffeine could be coursing through your body for longer than you might consider when ordering that 20-ounce latte, the dietitians we spoke to generally recommend cutting off significant caffeine consumption between 12 PM and 2 PM, or at the very latest, six hours before bedtime.
If you’re really craving a coffee pick-me-up in the afternoon or before a pre-dinner workout, you can test out your personal caffeine boundaries to see what works best for you and your sleep quality.
“Some people can still enjoy foods and beverages with a lower caffeine content such as green tea or dark chocolate in the evening without affecting sleep,” Harris-Pincus adds.
Can You Make Caffeine Wear Off Faster?
“Although there is no proven, safe way to help caffeine wear off faster, there are three powerful tools you can implement to reduce potential negative symptoms of caffeine overload,” according to Stewart:
Drink water. Do so before consuming caffeine to support your hydration status and possibly quiet any jittery sensations.
Eat before—or as—you eat or drink your source of caffeine. This will give you a steadier release of caffeine in the bloodstream. “Since you absorb caffeine via your stomach, the rate will be faster when your belly is empty,” Largeman-Roth says. “Even a banana is better than nothing.”
Move your body. Physical activity can help relieve caffeine-induced jitters.
Deep breathing and relaxation exercises, like meditation, can also help cool your jets. But “ultimately, time is needed to allow your body to clear the caffeine,” Harris-Pincus says.
It’s wise to tune into your body as you sip that coffee or tea or chow down on chocolate. If you’re starting to feel jittery, anxious, or like your heart rate is picking up, stop and don’t consume the rest of it, and mention this to your doctor at your next check-up.
Caffeine is a central nervous stimulant found naturally in coffee, tea, and chocolate. It’s also added to things like soda, energy drinks, and pre-workout drinks, snacks, and supplements. Generally, caffeine starts affecting the body within five minutes, and the ripple effects last about four to six hours. Genetics, medications, body size, activity levels, whether you smoke or not, and certain medications impact how long it takes for caffeine to kick in and how long it takes for the jolt to wear off.
Feel free to consume caffeine before a workout if that feels good for you; it may make a workout that was once very tough feel a bit less daunting.
If you consumed too much caffeine—or did so later in the day than you’d like—there’s no secret to help caffeine “wear off” faster. Still, staying hydrated, eating something as you consume your caffeine, and going for a walk or doing a workout can ease the jittery sensation.
Try to cap caffeine consumption by 2 PM (or at least six hours before bedtime), and if you notice that you’re particularly sensitive to caffeine, you may want to cool it sooner. This will allow you to still enjoy riding the wave of caffeine’s kick without sacrificing a solid night of sleep ahead.
This content is for informational and educational purposes only and does not constitute individualized advice. It is not intended to replace professional medical evaluation, diagnosis, or treatment. Seek the advice of your physician for questions you may have regarding your health or a medical condition. If you are having a medical emergency, call your physician or 911 immediately.