Substance display

When taken by mouth: Caffeine is LIKELY SAFE for most healthy adults when used in doses up to 400 mg per day. This amount of caffeine is similar to what is found in about 4 cups of coffee.

Caffeine is POSSIBLY UNSAFE when taken by mouth for a long time or in high doses (>400 mg per day). Caffeine can cause insomnia, nervousness and restlessness, stomach irritation, nausea and vomiting, increased heart rate and respiration, and other side effects. Caffeine can make sleep disorders in patients with acquired immunodeficiency syndrome (AIDS) worse. Larger doses might cause headache, anxiety, agitation, chest pain, and ringing in the ears.

Caffeine is LIKELY UNSAFE when taken by mouth in very high doses as it can cause irregular heartbeats and even death. Products with very concentrated or pure caffeine have a high risk of being used in doses that are too high. Avoid using these products.

Special Precautions & Warnings:

Children: Caffeine is POSSIBLY SAFE when given by mouth or intravenously (by IV) to preterm infants under the advice and care of a healthcare professional. Caffeine is also POSSIBLY SAFE when used by children and adolescents in amounts commonly found in foods.

Pregnancy and breast-feeding: Caffeine is POSSIBLY SAFE in pregnant or breast-feeding women when used daily amounts of less than 300 mg. This is about the amount in about 3 cups of coffee. Consuming larger amounts during pregnancy or when breast-feeding is POSSIBLY UNSAFE. When consumed in larger amounts during pregnancy, caffeine might increase the chance of miscarriage and other problems. Also, caffeine can pass into breast milk, so nursing mothers should closely monitor caffeine intake to make sure it is on the low side. High intake of caffeine by nursing mothers can cause sleep disturbances, irritability, and increased bowel activity in breast-fed infants.

Anxiety disorders: Caffeine might make these conditions worse. Use with care.

Bipolar disorder: Too much caffeine might make this condition worse. In one case, a 36-year-old man with controlled bipolar disorder was hospitalized with symptoms of mania after drinking several cans of an energy drink containing caffeine, taurine, inositol, and other ingredients (Red Bull Energy Drink) over a period of 4 days. Use caffeine with care and in low amounts if you have bipolar disorder.

Bleeding disorders: There is concern that caffeine might aggravate bleeding disorders. Use caffeine with care if you have a bleeding disorder.

Heart conditions: Caffeine can cause irregular heartbeat in sensitive people. Use caffeine with caution.

Diabetes: Some research suggests that caffeine may affect the way the body uses sugar and might worsen diabetes. However, the effect of caffeinated beverages and supplements has not been studied. If you have diabetes, use caffeine with caution.

Diarrhea: Caffeine, especially when taken in large amounts, might worsen diarrhea.

Epilepsy: People with epilepsy should avoid using caffeine in high doses. Low doses of caffeine should be used cautiously.

Glaucoma: Caffeine increases the pressure inside the eye. The increase occurs within 30 minutes and lasts for at least 90 minutes after drinking caffeinated beverages.

High blood pressure: Consuming caffeine might increase blood pressure in people with high blood pressure. However, this effect might be less in people who use caffeine regularly.

Loss of bladder control: Caffeine can make bladder control worse by increasing frequency of urination and the urge to urinate.

Irritable bowel syndrome (IBS): Caffeine, especially when taken in large amounts, might worsen diarrhea in people with IBS.

Weak bones (osteoporosis): Caffeine can increase the amount of calcium that is flushed out in the urine. If you have osteoporosis or low bone density, caffeine should be limited to less than 300 mg per day (approximately 2-3 cups of coffee). It is also a good idea to get extra calcium to make up for the amount that may be lost in the urine. If you are generally healthy and getting enough calcium from your food or supplements, taking up to 400 mg of caffeine per day (3-5 cups of coffee) doesn't seem to increase the risk of getting osteoporosis. Older women with an inherited disorder that affects the way vitamin D is used should use caffeine with caution. Vitamin D works with calcium to build bones.

Parkinson disease: Taking caffeine with creatine might make Parkinson disease e get worse faster. If you have Parkinson disease and take creatine, use caffeine with caution.

Schizophrenia: Caffeine might worsen symptoms of schizophrenia. *