Malic Acid
Malic acid is a naturally occurring compound that plays a role in the complex process of deriving adenosine triphosphate (ATP; the energy currency that runs the body) from food.
"Malic acid is found in a wide variety of fruits and vegetables, but the richest source is apples, which is why malic acid is sometimes referred to as “apple acid.”"
Fibromyalgia
"A deficiency in humans is unlikely, since the body can produce malic acid."
"Healthy people do not need to take malic acid as a supplement. Research has been conducted with 1,200–2,400 mg of malic acid in combination with 300–600 mg of elemental magnesium."
"Current research does not indicate any adverse effects from the use of malic acid in moderate amounts. At the time of writing, there were no well-known drug interactions with malic acid."