Many people rely on a caffeine boost to kick-start the morning—but while coffee or tea may be an energizing way to start the day, drinking too much can backfire.
For most adults, the Food and Drug Administration says consuming up to 400 milligrams (mg) of caffeine each day—the amount found in two to three 12-ounce cups of coffee—is considered safe. Anything above that could cause negative effects, and for people sensitive to caffeine, even smaller amounts may trigger symptoms.
Wondering if you might be overdoing it on the caffeine? Here are eight signs to watch out for—and the safest ways to start cutting back.
It might sound counterintuitive, but feeling tired all the time could actually be a sign that you’re drinking too much caffeine. There are a couple of reasons for this.
First, caffeine can interfere with your sleep. The jolt you get from caffeine comes from its ability to block adenosine, a chemical that helps your brain wind down for sleep. You might start to feel more alert within 15 minutes of drinking a cup of coffee, but caffeine lingers in your system for much longer.
Its half-life is about five hours, meaning if you consume 100 mg of caffeine, around 50 mg could still be in your body five hours later. The more you consume, the longer it takes to metabolize, potentially disrupting your nightly shut-eye.
Plus, regular caffeine consumption can lead to tolerance. Over time, your body may build up more adenosine, meaning you’ll need even more caffeine to feel the same effect. So if you’re feeling sluggish despite your usual coffee or tea routine, it could be a sign you’re stuck in this cycle.
For some people, caffeine can lead to heart palpitations, the feeling that your heart is racing, fluttering, or pounding.
As a stimulant, caffeine can trigger these sensations in various ways, including by inhibiting the enzyme phosphodiesterase, which induces heart contractions. If you’re sensitive to caffeine or prone to heart arrhythmias, you might feel these effects more intensely.
The good news is that while caffeine-induced heart palpitations can feel scary or uncomfortable, they’re generally not a cause for concern, according to the American Heart Association.
Anyone who consumes caffeine may experience a temporary rise in blood pressure—a knock-on effect of caffeine blocking adenosine. While this increase is typically small for people without chronic hypertension who consume less than 400 mg a day, it appears to be greater for those who exceed that amount.
For instance, a 2024 study found that people who consumed 400 mg of caffeine daily had elevated blood pressure over time, and that the increase was even more pronounced for those drinking more than 600 mg of caffeine daily.
Too much caffeine can sometimes cause tummy troubles. Research shows this happens because caffeine can relax the lower esophagus sphincter (LES), the muscle where the esophagus meets the stomach. When this muscle is more relaxed than it should be, it can allow stomach acid to flow back into the esophagus and may also increase acid production. The result? An upset stomach or acid reflux symptoms, such as frequent burping or a burning sensation in the chest or throat.
Another hallmark sign of too much caffeine? Headaches, whether mild or more severe. One study found that consuming three servings or more of caffeine a day was linked to a higher risk of a migraine the same day or the next.
Scientists don’t fully understand why caffeine can trigger headaches, but it may have something to do with the way it affects blood vessels, causing them to constrict and then open back up.
Too much caffeine can make you feel jumpy and anxious. That’s because, by blocking adenosine, caffeine can increase the production of dopamine, overstimulating the nervous system. While one study found that the risk of anxiety increases with any amount of caffeine, the risk is especially heightened when intake exceeds 400 mg.
Are you getting dizzy spells more frequently? It could be your daily cup of joe at work. If you’re sensitive to caffeine or consuming too much, the substance is more likely to trigger effects like an increased heart rate, blood pressure, and reduced blood flow to the brain. All of these changes could make you feel lightheaded and unstable on your feet.
The more caffeine you drink, the more your body relies on it—and the more likely you are to feel withdrawal symptoms if you suddenly stop. If you used to skip your morning coffee or tea without a problem but now feel suddenly off without it, that could be a sign that you’re drinking too much caffeine.
Common symptoms of caffeine withdrawal include:
- Nausea
- Difficulty focusing
- Headaches
- Drowsiness
- Feeling irritable
These symptoms usually start 12 to 24 hours after your last serving of caffeine and typically resolve within a few days. In some cases, they may last for up to a week.
If you’re experiencing any of the symptoms mentioned and want to cut back on caffeine, it’s best to be strategic to avoid unpleasant withdrawal effects. Here are some tips:
- Switch to tea: Theresa Gentile, RDN, CDN, a spokesperson for the Academy of Nutrition and Dietetics, told Health she recommends making the switch from coffee to tea, which contains less caffeine than coffee. Herbal, green, or matcha teas can be good options.
- Try the step-down method: “Begin to reduce your daily caffeine intake little by little,” Amy Bragagnini, RD, CSO, a spokesperson for the Academy of Nutrition and Dietetics and a clinical oncology dietitian at Trinity Health Richard J. Lacks Sr. Cancer Center in Grand Rapids, Michigan, told Health. “Have one less cup of coffee or energy drink each day and find satisfying alternatives for these beverages.”
- Eat a balanced diet: “If you always need caffeine to act as a ‘pick me up’ after lunch, it could be beneficial to make sure you are consuming adequate amounts of protein and complex carbohydrates at lunch,” said Bragagnini. “Aim to limit intake of foods and beverages high in added sugar.”
Experts say that up to 400 mg of caffeine per day is generally considered safe, but if you’re sensitive to caffeine, even smaller amounts can cause unwanted symptoms. Signs like jitteriness, headaches, high blood pressure, and sleep problems might mean it’s time to scale back your caffeine intake. To start, consider swapping in caffeine-free or low-caffeine alternatives like green tea. Also try to eat a well-balanced, nutrient-rich diet to support energy levels and help keep caffeine cravings at bay.
