From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history

Caffeine is a central nervous system stimulant and the active ingredient in coffee.[1][2][3] For most healthy people, it is not harmful to consume up to 400mg of caffeine a day.[3][4]

Uses[edit | edit source]

Caffeine occurs naturally in coffee, tea, cocoa, chocolate, guarana, and many other plants, foods and drinks.[2][3] Caffeine can also be taken as a supplement and may be added to other food or drinks, especially energy drinks.[4]

Caffeine is typically used for:

Energy drinks[edit | edit source]

Drinks marketed as energy drinks or sometimes sports drinks typically contain a number of different stimulants, including:

Energy drink brands include such as Spike Shooter, Pimp Juice, Red Bull, and Cocaine. [5]

Caffeine powder[edit | edit source]

The FDA has issued a warning against the use of caffeine powder, which can provide 1200mg of caffine per 0.15 tablespoons of pure caffeine, this is three times the suggested safe daily limit and a level high enough to cause toxic effects, including seizures.[4]

Theory[edit | edit source]

Evidence[edit | edit source]

Perscription drugs[edit | edit source]

Caffeine is FDA-approved for:

  • migraine and tension-type headaches, when combined pain relief drugs
  • Preventing headaches after surgery (for people who regularly consume caffeine)
  • Caffeine citrate is approved for pauses in breathing that may be followed by low heart rate and low oxygen levels in newborns.

ME/CFS[edit | edit source]

Many people with ME/CFS use caffeine to improve mental alertness or concentration or to reduce fatigue in the short term, but the 2014 International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis primer cautions against excessive usage due to the risk of tachycardia and agitation.[6] Consuming caffeine in the afternoon or evening is also advised against for ME/CFS patients due to the likelihood of it causing or contributing to insomnia.[6] Adolescents and children with ME/CFS are advised to limit the use of caffeine for concentration/attention to times when it is particularly important, such as for exams, and to be aware of the caffeine found in energy drinks.[7]

Risks and side effects[edit | edit source]

For most adults, a limit of 400mg of caffeine daily is likely to be safe, although this may not necessarily be safe long term.[3][4] Just four cups of brewed coffee, ten cans of cola or two typical energy shot drinks provide the maximum recommended amount of 400mg of caffeine.[3] Caffeine sensitivity varies greatly between people so some people will experience harmful effects at much lower doses.[4]

High doses[edit | edit source]

Large doses of caffeine can cause serious adverse reactions, including even fatalities resulting from excessive consumption, especially in the form of "energy" drinks or caffeine powder.[4][5][8][2][3]

Caffeine is mildly addictive, but other substances found in energy drinks are more addictive.[8] Caffeine withdrawal is not considered dangerous.

Excessive caffeine intake causes:

Interactions[edit | edit source]

Caffeine may interact with certain perscription drugs or other supplements, particularly:

  • Ephedrine, which is used in decongestants
  • Theophylline, a medication used to open up bronchial airways.
  • Echinacea, a herbal supplement sometimes used to prevent colds or other infections[3]

Costs and availability[edit | edit source]

Very widely available and inexpensive.

Notable studies[edit | edit source]

  • 2015, Brain-derived neurotrophic factor concentration may not be depressed in chronic fatigue syndrome[9] - (Abstract)

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. 1.0 1.1 "Caffeine". MedlinePlus. Retrieved May 23, 2022.
  2. 2.0 2.1 2.2 2.3 2.4 "CAFFEINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews". WebMD. Retrieved May 23, 2022.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 "Caffeine: How much is too much?". Mayo Clinic. Retrieved May 23, 2022.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Office of the Commissioner (December 2, 2021). "Spilling the Beans: How Much Caffeine is Too Much?". Food and Drug Administration. Retrieved May 23, 2022.
  5. 5.0 5.1 5.2 Clauson, Kevin A.; Shields, Kelly M.; McQueen, Cydney E.; Persad, Nikki (May 1, 2008). "Safety issues associated with commercially available energy drinks". Journal of the American Pharmacists Association. 48 (3): e55–e67. doi:10.1331/JAPhA.2008.07055. ISSN 1544-3191.
  6. 6.0 6.1 International Association for Chronic Fatigue Syndrome / Myalgic Encephalomyelitis; Friedberg, Fred; Bateman, Lucinda; Bested, Alison C; Davenport, Todd; Friedman, Kenneth J; Gurwitt, Alan R; Jason, Leonard A; Lapp, Charles W; Stevens, Staci R; Underhill, Rosemary A; Vallings, Rosamund (2014), Chronic Fatigue Syndrome Myalgic Encephalomyelitis Primer for Clinical Practitioners (PDF), Chicago, USA: International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis
  7. Rowe, Peter C.; Underhill, Rosemary A.; Friedman, Kenneth J.; Gurwitt, Alan; Medow, Marvin S.; Schwartz, Malcolm S.; Speight, Nigel; Stewart, Julian M.; Vallings, Rosamund; Rowe, Katherine S. (2017). "Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Diagnosis and Management in Young People: A Primer". Frontiers in Pediatrics. 5: 121. doi:10.3389/fped.2017.00121.
  8. 8.0 8.1 Calabrò, Rocco S.; Naro, Antonino; Bramanti, Placido (2016). "Chapter 72 - Caffeine and Taurine and Energy Drink Abuse". In Preedy, Victor R. (ed.). Neuropathology of Drug Addictions and Substance Misuse. 3. San Diego: Academic Press. pp. 723–732. ISBN 978-0-12-800634-4.
  9. Patrick, David M.; Miller, Ruth R.; Steiner, Theodore; Gardy, Jennifer L.; Parker, Shoshana M.; Tang, Patrick (April 3, 2015). "Brain-derived neurotrophic factor concentration may not be depressed in chronic fatigue syndrome". Fatigue: Biomedicine, Health & Behavior. 3 (2): 122–125. doi:10.1080/21641846.2015.1024004. ISSN 2164-1846.