The legend of this chemical element states that anyone should produce it after a certain exercise intensity. Its name suggest a relationship with milk, from the Latin word "lactis", and in fact it plays an important role in fermentation. Different bacteria produce lactic acid like lactobacillus y streptococcus. Also found in sourdough bread, giving it a characteristic taste. Finally wine is as well between the most common sources.
While a group says that it's an enemy of the body performance for sport, others consider this statement false arguing that it's a method to produce glucose thus not simply a byproduct of anaerobic situations.
This is a rather strong discrepancy with antagonistic consequences and a big door for placebo effects. The organism complexity is extreme, with trillions of pieces so these mechanisms are still being studied with theories here and there.
Any study gets still more complicated when the differences between individuals are very considerable. Maybe the recommended policy for who is worried about performance would be using technical aid for knowing what is best for a particular case.
There are apparatus that measure lactic acid in the blood within mere seconds. To fight any acidosis, there are alkaline nutrients that should counteract it reestablishing a supposedly better balance.
A topic of interest for sports minded people!