- What other names is Caffeine known by?
- What is Caffeine?
- How does Caffeine work?
- Are there safety concerns?
- Are there any interactions with medications?
- Dosing considerations for Caffeine.
Caffeine is most commonly used to improve mental alertness, but it has many other uses. Caffeine is used by mouth or rectally in combination with painkillers (such as aspirin and acetaminophen) and a chemical called ergotamine for treating migraine headaches. It is also used with painkillers for simple headaches and preventing and treating headaches after epidural anesthesia.
Some people use caffeine by mouth for asthma, gallbladder disease, attention deficit-hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), low oxygen levels in the blood due to exercise, Parkinson's disease, memory, cramping, liver cirrhosis, Hepatitis C, stroke, recovery after surgery, decreasing pain, muscle soreness from exercise, age-related mental impairment, shortness of breath in newborns, and low blood pressure. Caffeine is also used for weight loss and type 2 diabetes. Very high doses are used, often in combination with ephedrine, as an alternative to illegal stimulants.
Caffeine is one of the most commonly used stimulants among athletes. Taking caffeine, within limits, is allowed by the National Collegiate Athletic Association (NCAA). Urine concentrations over 15 mcg/mL are prohibited. It takes most people about 8 cups of coffee providing 100 mg/cup to reach this urine concentration.
Caffeine creams are applied to the skin to reduce redness and itching in dermatitis.
Healthcare providers sometimes give caffeine intravenously (by IV) for headache after epidural anesthesia, breathing problems in newborns, and to increase urine flow.
In foods, caffeine is used as an ingredient in soft drinks, energy drinks, and other beverages.
People with voice disorders, singers, and other voice professionals are often advised against using caffeine. However, until recently, this recommendation was based only on hearsay. Now developing research seems to indicate that caffeine may actually harm voice quality. But further study is necessary to confirm these early findings.
- Migraine headache. 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.
- Headache following surgery. Using caffeine by mouth or intravenously is effective for preventing headaches following surgery. Caffeine is an FDA-approved product for this use in people who regularly consume products that contain caffeine.
- Tension headache. Taking caffeine by mouth in combination with pain relievers is effective for treating tension headaches.
Likely Effective for...
- Mental alertness. Research suggests that drinking caffeinated beverages throughout the day keeps the mind alert. Combining caffeine with glucose as an "energy drink" seems to improve mental performance better than either caffeine or glucose alone.
Possibly Effective for...
- Asthma. Caffeine appears to improve airway function for up to 4 hours in people with asthma.
- Athletic performance. Taking caffeine seems to increase physical strength and endurance and might delay exhaustion. It might also reduce feelings of exertion and improve performance during activities such as cycling, running, playing soccer, and golfing. However, caffeine does not seem to improve performance during short-term, high-intensity exercise such as sprinting and lifting.
- Diabetes. Drinking beverages that contain caffeine is linked with a lower risk of developing type 2 diabetes. It appears that the more caffeine that is consumed, the lower the risk. Although caffeine might help prevent type 2 diabetes, it might not be effective in treating type 2 diabetes. Research on the effects of caffeine in people with type 1 diabetes is inconsistent. Some research shows benefit, while other research does not.
- Gallbladder disease. Drinking beverages that provide at least 400 mg of caffeine daily seems to reduce the risk of developing gallstone disease. The effect seems to be dose-dependent. Taking 800 mg of caffeine daily seems to work best.
- Low blood pressure after eating. Drinking caffeinated beverages seems to increase blood pressure in older people with low blood pressure after eating.
- Memory. Taking 200 mg of caffeine by mouth daily seems to improve memory in some people with outgoing personalities and college students.
- Breathing problems in infants. Caffeine given by mouth or intravenously (by IV) appears to improve breathing in infants born too early. It seems to reduce the number of episodes of shortness of breath by at least 50% over 7-10 days of treatment. However, caffeine does not seem to reduce the risk of premature infants developing breathing problems.
- Pain. Research suggests that taking caffeine together with painkillers can reduce pain.
- Parkinson's disease. Some research suggests that people who drink caffeinated beverages have a decreased risk of Parkinson's disease. However, this reduced risk is not observed in people who smoke cigarettes.
- Headache after epidural anesthesia. Taking caffeine by mouth or intravenously seems to help prevent headache after epidural anesthesia.
- Weight loss. Taking caffeine in combination with ephedrine seems to help reduce weight, short-term. Taking 192 mg of caffeine in combination with 90 mg of ephedra daily for 6 months seems to cause a modest weight reduction (5.3 kg or 11.66 pounds) in overweight people. This combination, along with limiting fat intake to 30 percent of calories and moderate exercise, also seems to reduce body fat, decrease "bad" low-density lipoprotein (LDL) cholesterol, and increase "good" high-density lipoprotein (HDL) cholesterol. However, there can be unwanted side effects. Even in carefully screened and monitored otherwise healthy adults, caffeine/ephedra combinations can cause changes in blood pressure and heart rate.
Possibly Ineffective for...
- Attention deficit-hyperactivity disorder (ADHD). Most research suggests that caffeine does not reduce ADHD symptoms in children. The use of caffeine in adolescents and adults with ADHD has not been studied.
Insufficient Evidence to Rate Effectiveness for...
- Age-related mental problems. Early research suggests that consuming more than 371 mg of caffeine daily might help prevent mental decline in elderly women compared to those who consume less caffeine. Drinking caffeinated coffee is linked to slower mental decline, but not other caffeinated products such as tea.
- Cancer pain. Early research shows that receiving 200 mg of caffeine intravenously once daily for 2 days might reduce pain in people with advanced cancer.
- Depression. Some research suggests that caffeine intake is linked with an increased occurrence of depression symptoms in children. However, other research suggests that caffeinated coffee intake is linked to a decreased occurrence of depression in adults.
- Low levels of oxygen in the blood caused by exercise. Early research shows that taking caffeine may improve breathing during exercise, but does not affect blood levels of oxygen in athletes with low blood oxygen levels during exercise
- Muscle soreness during exercise. Some early research suggests that taking moderate doses of caffeine can reduce muscle pain during exercise, while lower doses may not help.
- Hepatitis C. Research suggests that higher intake of caffeine from coffee is linked to reduced liver scarring in people with hepatitis C.
- Headaches while sleeping. Some early evidence suggests that drinking a cup of coffee before bed or upon waking up might help alleviate pain associated with headaches that occur during sleep.
- Cramping due to narrowed arteries (intermittent claudication). Taking a single 6 mg dose of caffeine by mouth seems to improve walking and muscle strength in people with aching and cramping due to narrowed or blocked arteries.
- Liver cirrhosis. Research suggests that drinking coffee might reduce the risk for liver cirrhosis. However, it is unclear if this effect is due to caffeine or other components of coffee.
- Obsessive-compulsive disorder (OCD). Early research shows that adding caffeine to conventional therapy seems to decrease the severity of OCD symptoms.
- Stoke. Research shows that increased caffeinated or decaffeinated coffee intake is linked to a decreased risk of stroke in women. However, it is not clear if the effect is due to caffeine.
- Skin irritation, redness, and itching.
- Other conditions.
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).
Next: How does Caffeine work?
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