Caffeine Side Effects

image001 Caffeine is naturally found in certain plants, but it can also be produced synthetically and added to food products. Caffeine passes to the brain quickly when it is absorbed rather than being stored in the body or collecting in the bloodstream. Once it has entered the body, caffeine will pass through the body some time later through the urine. Caffeine is used to stimulate the nervous system and brain, but does not offer nutritional benefits. In some cases caffeine can be taken to temporarily relieve drowsiness or fatigue, but long term use of this product can lead to side effects.

Caffeine Side Effects

1. Common Side Effects

The most common side effects of caffeine intake include fast heartbeat, diarrhea, irritability, severe jitters, nervousness, tremors, nausea, trouble sleeping or vomiting. You may also experience hyperglycemia which can cause drowsiness, blurred vision, fruit like breath odors, flushed dry skin, ketones in urine, increased urination, nausea, loss of appetite, tiredness, stomachache, trouble breathing, vomiting or unusual thirst. Hypoglycemia may lead to cold sweats, anxiety, blurred vision, cool pale skin, confusion, excessive hunger, drowsiness, nervousness, shakiness, restless sleep, unusual tiredness or weakness.

2. Rare Side Effects

In less common cases people that experience a negative reaction to caffeine can see bloody diarrhea, abdominal or stomach bloating, unusual weakness or tiredness and dehydration.

3. Effects of Overdose

If you are experience an overdose of caffeine you may notice confusion or delirium, abdominal or stomach pain, convulsions, agitation, excitement, restlessness, anxiety, increased sensitivity to pain or touch, dehydration, fast or irregular heartbeat, increased breathing rate, irritability, fever, headache, overextending the body with the head and heels bent backward, muscle twitching or trembling, frequent urination, ringing in the ears, painful swollen abdomen, vomiting, whole body tremors or seeing zigzag flashes of light.

4. Side Effects to Watch Out For

Most of the side effects listed above do not require medical attention and will fade as the body gets used to caffeine. If using medications with caffeine, these symptoms are severe or impair your ability to function, your doctor may reduce doses of medications that contain caffeine. You should let your doctor know if you experience nervousness, jitters, nausea, muscle tension, headache, irritability, nervousness, stuffy nose, or unusual tiredness. You can work together with your doctor to determine how to address these issues to get relief.

Recommended Dosages of Caffeine

As too much intake of caffeine can lead to many side effects which have been mentioned above, it important to understand its dosage.

1. Caffeinated Medications

Used For



250mg daily



Improving Athletic Performance


Doses should not exceed 800mg per day to avoid violating standards of the National Collegiate Athletic Association.

Headache Following Epidural Anesthesia


Preventing Gallstone Disease

400mg or more daily

Preventing Parkinson’s Disease

421-2716mg, or a minimum of 124-208mg for men and 1-3 cups of coffee daily for women

2. Caffeinated Drinks


Amount of Caffeine

Recommended Dosage

Brewed Coffee

95-200 mg per cup

Three 8 oz. cups per day

Black Tea

40-120 mg per 8 oz.

5 servings per day

Green Tea

15-60 mg per 8 oz.

5 servings per day

Soft Drinks (Cola)

20-80 mg per 12.oz.

5 servings per day

Energy Drinks

48-300 mg per serving

5 servings per day

People Who Should Not take Caffeine

People that will need to restrict their intake of caffeine to small amounts or avoid it completely include:

Watch the amount of caffeine a child consumes carefully. Though it is safe for children to take in a small amount of caffeine, this is still a strong stimulant. Children that tend to be hyperactive should not use caffeine. It is also discouraged to take in large amounts of caffeine during pregnancy, though small amounts are generally considered to be safe.

Reducing Caffeine Intake

Those that would like to or need to cut back on the amount of caffeine they consume may find this process challenging. Suddenly cutting off your supply of caffeine can cause withdrawal effects like irritability, headaches, nervousness or fatigue. If these occur they should only last a few days, but taking other steps can help withdrawal effects from appearing altogether.

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