Malic acid (Hydroxybutanedioic acid, malate) is an organic compound that is made by all living organisms and it contributes to the sourness of green apples. It can also be found in grapes and in most wines. Malate is a very versatile substance as it can be found in all sorts of products from makeup and skin care products as well as sport enhancing supplements. Malic acid is also commonly used in foods like potato chips. Malic acid bound to ions or salts are known as malates.
Possible Benefits of Malic Acid for Exercise
When taken as supplement, malic acid is typically used to improve performance. However, no direct evidence exists for this use in healthy population.
Malate is involved in the production of energy in the body under both aerobic and anaerobic conditions. Malic acid has an active role in the Krebs cycle (citric acid cycle), aiding the conversion of food into energy.  Malic acid plays an important role in energy metabolism; specifically the generation of mitochondrial adenosine triphosphate (ATP) . Studies in rats show that only malic acid is depleted during exhaustive physical activity while other key metabolites from the citric acid cycle needed for energy production were found to be unchanged .
Malic acid has shown some promise in treating people with fibromyalgia syndrome (a musculoskeletal condition which characteristics include joint pain and fatigue) . However, people with fibromyalgia syndrome are probably malic acid and magnesium deficient . According to one clinician, malic acid increases tolerance to exercise in 40 percent of patients with chronic fatigue syndrome .
Malic Acid Side Effects
Malic acid is generally considered safe since it can be found in various fruits that are usually consumed daily. However, due to a lack of research, little is known about the safety of long-term use of malic acid supplements. No serious or dangerous side effects are reported regarding malic acid ingestion when consumed at recommended doses.
- Citric Acid Cycle Reactions. Retrieved from http://www.elmhurst.edu/, 1. Avgust 2013
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Russell, I. J., et al. “Treatment of fibromyalgia syndrome with Super Malic: a randomized, double-blind, placebo controlled, crossover pilot study.” The Journal of rheumatology 22.5 (1995): 953.
Abraham, Guy E., and Jorge D. Flechas. “Management of fibromyalgia: rationale for the use of magnesium and malic acid.” Journal of Nutritional and Environmental Medicine 3.1 (1992): 49-59.