In addition to giving you a boost of energy, caffeine may lower your risk of certain conditions. But consuming too much can lead to less desirable effects like headaches, confusion, and high blood pressure.

Many of us rely on a morning cup of coffee or a jolt of caffeine in the afternoon to help us get through the day. Caffeine is so widely available that the U.S. Food and Drug Administration (FDA), says about 80 percent of U.S. adults take some form of caffeine every day. But caffeine does so much more than just keeping you awake. It’s a central nervous system stimulant that affects your body in numerous ways.

Knowing the symptoms of caffeine and its long-term effects on your body may make you think twice about having that fourth cup of coffee. Read on to learn more about these effects.

Caffeine provides no nutritional value on its own. It’s tasteless, so you won’t necessarily know if it’s in your food either. Even some medications may contain caffeine without your knowledge.

This ingredient almost always causes some symptoms. At a minimum, you may feel more energetic, but over time, too much caffeine may cause withdrawal symptoms. According to the Mayo Clinic, it’s safe for most healthy adults to consume up to 400 milligrams of caffeine per day. Keep in mind that a standard size cup of coffee is eight ounces. If you’re using a mug or getting your fix at a coffee house, chances are you’re drinking 16 ounces or more, so reading labels is important.

As you consume the same amount of caffeine on a daily basis, your body develops a tolerance to it. Other factors like your age, body mass, and overall health can determine your tolerance to caffeine, too. If you want to decrease the amount of caffeine you take, it’s best to decrease your consumption slowly.

Caffeine acts as a central nervous system stimulant. When it reaches your brain, the most noticeable effect is alertness. You’ll feel more awake and less tired, so it’s a common ingredient in medications to treat or manage drowsiness, headaches, and migraines.

Studies have also found that people who drink coffee regularly have a lower risk of developing Alzheimer’s and dementia, and cut suicide risk by 45 percent. These benefits are limited to people who drink high-octane coffee, not decaf. Some people consider coffee to be a health drink, but like most foods, over indulging can cause side effects.

For example, too much caffeine can give you headaches. This is primarily linked to caffeine withdrawal. The blood vessels in your brain become used to caffeine’s effects so if you suddenly stop consuming caffeine, it can cause a headache.

Other symptoms of caffeine withdrawal include:

In some people, sudden withdrawal may cause tremors.

Although it’s extremely rare, it’s also possible to overdose on caffeine. Symptoms of an overdose include:

An overdose can result in death due to convulsions. Overdosing happens by consuming large amounts of caffeine, most often in energy drinks or diet pills. Up to 400 milligrams of caffeine is considered to be safe, according to the Mayo Clinic. This equals about 4 cups of coffee, although the amount of caffeine in beverages varies widely.

Caffeine increases the amount of acid in your stomach and may cause heartburn or upset stomach. Extra caffeine doesn’t get stored in your body either. It’s processed in the liver and exits through your urine. This is why you might have an increase in urination shortly after having caffeine.

If you have experience stomach problems, like acid reflux or ulcers, ask your doctor if it’s okay for you to have caffeine.

Caffeine is absorbed from your stomach. It reaches its highest levels in your bloodstream within an hour or two.

Caffeine can make your blood pressure go up for a short time. This effect is thought to be attributed to either an increase in adrenaline or a temporary block on the hormones that naturally widen your arteries. In most people, there is no long-term effect on blood pressure, but if you have irregular heart rhythms, caffeine may make your heart work harder. If you have high blood pressure (hypertension) or heart-related problems, ask your doctor if caffeine is safe for you to consume.

An overdose of caffeine may cause rapid or irregular heartbeat and breathing trouble. In rare cases, caffeine overdose can result in death due to convulsions or irregular heartbeat.

Caffeine in large amounts may interfere with absorption and metabolism of calcium. This can contribute to bone thinning (osteoporosis).If you consume too much, caffeine may cause also your muscles to twitch.

If experiencing caffeine withdrawal, a symptom may include achy muscles.

Caffeine travels within the bloodstream and crosses into the placenta. Since it’s a stimulant, it can cause your baby’s heart rate and metabolism to increase. Too much caffeine can also cause slowed fetal growth and increased risk of miscarriage. In most cases, a little caffeine is safe during pregnancy.

According to the Mayo Clinic, you should limit caffeine consumption between 200 and 300 milligrams per day if you’re trying to get pregnant. There’s some evidence that large amounts of caffeine can interfere with the estrogen production and metabolism needed to conceive.