Why Coffee Doesn’t Wake You Up

The smell of a freshly brewed cup of coffee is always nice to wake up to, but what if that coffee isn’t waking you up? You may feel like the odd one out if coffee isn’t having the same awakening effect for you that it seems to have for so many people.

Man yawning while holding a cup of coffee

Coffee’s stimulating effects on regular coffee drinkers can diminish over time. There are also people who have never felt the effects of caffeine, but they still want to know why.

This post covers some of the reasons why your energy level might not be going up when you drink coffee.

First, let’s discuss go over the way caffeine works—or is supposed to work—on your body.

Effects of Caffeine on the Body

Every cell in your body has little proteins known as adenosine receptors. Think of them as little docks, and the ship that docks in them is a chemical called adenosine.

Adenosine slows down neural activity when it “docks” in these receptors. This is what makes you feel drowsy or sleepy.

It just so happens that caffeine is a pretty nice fit for those adenosine receptors as well, and caffeine does nothing to slow down neural activity. So when you drink coffee, the caffeine becomes like a trespassing ship that prevents adenosine from docking in its usual spot. The neural activity is not slowed, and you don’t get drowsy or sleepy. You feel alert.

Sculpture of a caffeine molecule suspended in a brick of glass
The chemical structure of a caffeine molecule shares some features of adenosine.

Some other things are going on as well. Your pituitary gland senses that neural activity is higher than it ought to be, so it perceives an emergency and releases adrenaline. This increase your heart rate and blood pressure, which may rev you up a bit or even improve your physical performance.

This is generally how it works, but these effects vary from person to person. They depend on a number of factors such as age, weight and caffeine tolerance.

Reasons Why Caffeine May Not Be Working for You

1. Lack Of Sleep

Inadequate sleep is the No. 1 reason you might be missing that boost from coffee. Simply put, your tiredness could be overriding caffeine’s effects.

If you drink coffee regularly, caffeine could also be interfering with your sleep quality. This creates a cycle of dependency: Caffeine keeps you up at night, making you tired during the day, which prompts you to drink more coffee to perk up, which disrupts your sleep, etc…

Man struggling to stay awake with coffee at his computer

So getting enough sleep is job number one. Yes, coffee is a nice stimulant, but it’s not a miracle-worker. If it’s not working for you, you might just need more sleep.

2. Too Much Caffeine

If you’ve ever had too much coffee, you know about the negative side effects: jitters, anxiety, headaches.

What you might not have realized is that drinking too much coffee can also lead to caffeine tolerance, which we’ll discuss further below.

There is no right or wrong amount of caffeine that suits all people, but the general guideline from the Food and Drug Administration (FDA), based on scientific research, is that 400 milligrams a day is the maximum that’s safe for healthy adults to consume.

However, about half the population carries a genetic variant that slows their caffeine metabolism. It takes their bodies longer to process caffeine in their blood. This can lead to kidney problems, according to a 2023 study. These folks should probably stop short of the recommended 400 mg limit.

Each cup of medium-roast coffee contains an average of 80-120 milligrams of caffeine, so this limit should allow you 3-5 cups a day, depending on the serving size.

Overhead shot into a cup of coffee
There’s a good 100 grams or so of caffeine in that cup, so careful how many you drink.

We would argue that if you’re regularly pushing that limit, you are building up a tolerance to caffeine.

3. Tolerance to Caffeine

Caffeine tolerance means you’re unlikely to experience unwanted side effects. That’s the good news. The bad news is, it’s probably not going to do much to wake you up.

So how does caffeine tolerance happen?

Remember those adenosine receptors in your cells that we talked about? Those little docks for the adenosine ship?

When you drink lots of coffee, caffeine intrudes on those receptors. Your body’s response is to produce more of them. You build more docks. Once again, adenosine has places to bind and  the effects of caffeine become muted. This was discovered in a 1983 study out of the National Institute of Mental Health.

If you want to avoid building up caffeine tolerance so you can always rely on a coffee boost, you should reduce your overall caffeine intake and/or take regular breaks from coffee consumption.

One way to do this is by alternating between regular and decaf coffee. Drinking tea can also help reduce caffeine tolerance.

4. Dehydration

Have you ever tried physical activity on a hot day without enough water? You get dehydrated, and you fatigue very easily. You might be dehydrated if you’re not getting a boost from your coffee.

Remember, caffeine is also a diuretic which helps rid your body of water and salt. That’s why it makes you pee a lot.

If you’re a bit dehydrated, a diuretic like caffeine will make you even more so. It’s no wonder you can feel fatigued.

Drink plenty of water throughout the day to stay hydrated and allow your coffee to do its thing.

Woman holding out glass of water

5. Genetic Variations in Caffeine Sensitivity

Our genes help shape our adenosine receptors, which is one of the reasons some people are naturally more or less sensitive to caffeine. If you’ve never gotten much of a boost from coffee, you may just be one of those people whose adenosine receptors aren’t greatly affected by caffeine.

Try to understand your genetic predisposition to caffeine sensitivity, and you’ll be better able to manage your caffeine intake.

6. Time of Day

Caffeine can have different effects at different times of the day. Your body has natural circadian rhythms that govern alertness levels throughout any 24-hour period. If your coffee consumption is in conflict with those rhythms, it might not do much to wake you up.

And as we’ve discussed, drinking coffee later in the day can interfere with sleep quality, making it harder to feel the effects of caffeine the following day

7. Type of Coffee

The type of coffee you drink can affect caffeine content. The caffeine in coffee beans undergoes conversion to other compounds when the beans are roasted. The longer they’re roasted, the more caffeine is converted. This means lighter roasts will have more caffeine and darker roasts will have less. If you’re not getting a boost from your coffee, try a lighter roast.

Coffee beans at various stages of a roast
Coffee beans at various stages of a roast. Clockwise from top left: Raw (or green), light roast, dark roast, medium roast.

Robusta beans also have more caffeine than arabica beans. Switching from arabica to a blend that includes a significant proportion of robusta might increase your chances of feeling that jolt. Most blends that are explicit labelled espresso will contain some robusta.

How to Get Better Stimulation From Coffee

If your morning cup of coffee is no longer working its stimulative magic on you—or never has—here are a few things to try…

Monitor Your Caffeine Intake

Be aware of how much caffeine you’re taking in. You want to avoid overconsumption, to minimize negative effects and prevent your body from becoming immune to caffeine’s stimulating effects.

Make sure you have a rough idea of the caffeine content in your coffee. The caffeine per cup will depend on the type of bean, type of roast, volume and concentration.

Also think about whether you’re consuming other sources of caffeine throughout the day. Keep in mind that coffee might not be the only thing you’re consuming that contains caffeine. 

For example, you’ll also find it in:

  • matcha tea
  • yerba mate
  • chai
  • chocolate
  • energy drinks

All these things can contribute to buildup of caffeine tolerance.

Reducing your caffeine intake or taking a break from caffeinated beverages for a while can also help reduce your tolerance and make coffee work for you.

Drink Lots of Water

Staying hydrated helps prevent fatigue and may make caffeine more effective. Of course, drinking water also helps with digestion and improves overall health and well-being.

6 Ways to Feel More Energetic Without Using Caffeine

Don’t become too dependent on your morning coffee for energy. There are plenty of other ways to get it that don’t include caffeine at all:

  1. Get enough sleep. Aim for seven or eight hours of sleep per night to help your body recharge and feel more alert.
  2. Exercise. Physical activity can help improve blood flow and oxygen levels, boosting energy levels and reducing fatigue.
  3. Eat a balanced diet. Consuming a diet rich in fruits, vegetables, lean protein, and healthy fats can help provide sustained energy throughout the day.
  4. Stay hydrated. Drinking plenty of water throughout the day can help prevent dehydration, which can cause fatigue and drain energy.
  5. Take breaks. Regularly taking short breaks from work throughout the day can help refresh your mind and reduce mental fatigue.
  6. Reduce stress. Stress is a major energy drainer. Finding ways to manage stress, such as through mindfulness practices, exercise, or spending time in nature, can help boost your energy.

If you’re puzzled as to why coffee doesn’t wake you up, we hope we’ve given you some food for thought here. 

The bottom line is that coffee isn’t magic, despite how many of us feel about it. It’s just chemistry, and all chemical compounds we ingest are affected by what else is going on in our bodies.

By paying attention to what’s going on in your body, you should eventually be able to find the right balance that allows coffee to give that energy boost when you require it.