Overview
Caffeine is a natural chemical with stimulant effects. It is found in coffee, tea, cola, cocoa, guarana, yerba mate, and over 60 other products.
Caffeine works by stimulating the central nervous system, heart, muscles, and the centers that control blood pressure. Caffeine can raise blood pressure, but might not have this effect in people who use it all the time. Caffeine can also act like a "water pill" that increases urine flow.
People most commonly use caffeine for mental alertness, headache, migraine, athletic performance, memory, and obesity. It is also used for asthma, gallbladder disease, ADHD, low blood pressure, depression, and many other conditions, but there is no good scientific evidence to support most of these other uses.
Caffeine products sold in very concentrated or pure forms are a health concern. People can easily take doses that are much too high by mistake. It's illegal in the US for these products to be sold to consumers in bulk. Taking caffeine, within limits, is allowed by the National Collegiate Athletic Association (NCAA). Urine concentrations over 15 mcg/mL are prohibited.
Uses & Effectiveness ?
Effective for
- Migraine. Taking caffeine by mouth together with pain relievers such aspirin and acetaminophen is effective for treating migraines. Caffeine is an FDA-approved product for use with pain relievers for treating migraine headaches.
- Pauses in breathing that may be followed by low heart rate and low oxygen levels in newborns. Giving caffeine by mouth or by IV can improve breathing in very premature infants. Caffeine citrate is approved as a prescription drug for this condition. IV products can only be given by a healthcare provider.
- Headache after surgery. Taking caffeine by mouth or by IV is effective for preventing headaches following surgery. Caffeine is an FDA-approved product for this use in people who regularly consume caffeine. IV products can only be given by a healthcare provider.
- Tension headache. Taking caffeine by mouth in combination with pain relievers is effective for treating tension headaches. It is FDA-approved for this use.
Likely Effective for
- Mental alertness. Taking caffeine by mouth improves mental alertness. But it might not be as effective as getting enough sleep.
Possibly Effective for
- Athletic performance. Taking caffeine by mouth seems to increase physical strength and endurance and might delay fatigue during exercise. But taking more than 800 mg of caffeine daily (6-8 cups) can lead to caffeine levels greater than those allowed by the National Collegiate Athletic Association (NCAA).
- A lung disease that affects newborns (bronchopulmonary dysplasia). Giving caffeine by mouth or by IV to premature infants seems to reduce the risk for this lung problem. IV products can only be given by a healthcare provider.
- Diabetes. Drinking beverages that contain caffeine is linked with a lower risk of developing type 2 diabetes. But it's not clear if consuming caffeine helps to treat diabetes.
- Memory. Taking caffeine by mouth seems to improve short-term memory in college students or people with outgoing personalities.
- Obesity. Taking caffeine by mouth together with ephedrine seems to increase weight loss, short-term. But there can be unwanted side effects. Even in carefully monitored and otherwise healthy adults, caffeine/ephedra combinations can cause changes in blood pressure and heart rate.
- Acute pain. Taking caffeine by mouth together with painkillers such as ibuprofen can reduce pain more than painkillers alone.
- Headache after epidural anesthesia, spinal anesthesia, or lumbar puncture. Taking caffeine by mouth or by IV seems to help prevent headache that can occur after these procedures. IV products can only be given by a healthcare provider.
Possibly Ineffective for
- Irregular heartbeat (atrial fibrillation). Taking caffeine by mouth does not reduce the risk for this type of irregular heart rhythm following heart surgery.
- Attention deficit-hyperactivity disorder (ADHD). Taking caffeine by mouth doesn't reduce ADHD symptoms in children.
There is interest in using caffeine for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Side Effects
When taken by mouth: Caffeine is likely safe for most healthy adults when used in doses up to 400 mg daily. This is equal to about 4 cups of coffee.
Caffeine is possibly unsafe when used for a long time or in doses over 400 mg daily. Caffeine can cause insomnia, nervousness, restlessness, nausea, increased heart rate, and other side effects. Larger doses might cause headache, anxiety, and chest pain.
Caffeine is likely unsafe when used in very high doses. It can cause irregular heartbeat 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 and Warnings
When taken by mouth: Caffeine is likely safe for most healthy adults when used in doses up to 400 mg daily. This is equal to about 4 cups of coffee.
Caffeine is possibly unsafe when used for a long time or in doses over 400 mg daily. Caffeine can cause insomnia, nervousness, restlessness, nausea, increased heart rate, and other side effects. Larger doses might cause headache, anxiety, and chest pain.
Caffeine is likely unsafe when used in very high doses. It can cause irregular heartbeat 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.
Pregnancy and breast-feeding: Caffeine is possibly safe during pregnancy and breast-feeding when used in amounts commonly found in foods. Consuming up to 300 mg of caffeine daily appears to be safe. This is about the amount in 3 cups of coffee. Consuming larger amounts during pregnancy or when breast-feeding is possibly unsafe. Caffeine might increase the chance of miscarriage and other problems. Caffeine can also pass into breast milk. High caffeine intake while nursing can cause sleeping problems, irritability, and increased bowel activity in breast-fed infants.
Children: Caffeine is possibly safe when used by children and adolescents in amounts commonly found in foods.
Anxiety disorders: Caffeine might make these conditions worse. Use caffeine cautiously and in low amounts if you have anxiety.
Bipolar disorder: Too much caffeine might make this condition worse. Use caffeine cautiously and in low amounts if you have bipolar disorder.
Bleeding disorders: Caffeine might aggravate bleeding disorders. Use caffeine cautiously if you have a bleeding disorder.
Heart conditions: Caffeine can cause irregular heartbeat in sensitive people. Use caffeine with caution.
Diabetes: Caffeine might affect the way the body uses sugar. 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. But this does not seem to be a major concern 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 daily (approximately 2-3 cups of coffee).
Parkinson disease: Taking caffeine with creatine might make Parkinson disease worsen faster. If you have Parkinson disease and take creatine, use caffeine with caution.
Schizophrenia: Caffeine might worsen symptoms of schizophrenia.
Dosing
Caffeine is found in many foods and beverages, including coffee, teas, chocolate, and many sports and energy drinks. Coffee contains 95-200 mg of caffeine per cup. Black tea contains 25-110 mg of caffeine per cup. Green tea contains 30-50 mg of caffeine per cup. Caffeine products sold in very concentrated or pure forms are a health concern. People can easily take doses that are much too high by mistake. Avoid these products.
As medicine, caffeine has most often been used by adults in doses of 50-260 mg by mouth daily. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.
CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circ*mstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.
This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version.
© Therapeutic Research Faculty 2020.
