Does lactic acid cause muscle soreness?

“This is something you hear in the gym a lot,” says Dr. Jose Antonio, CEO of International Sports Nutrition and researcher at Florida’s Southeastern University. He says this myth doesn’t even get its terms right. “Lactic acid or lactate (actually the correct word) has nothing to do with delayed onset muscle soreness.” Dr. Antonio says the real culprit is micro-tearing in your muscle fibers during exercise. “Lactate is not a medical metabolic poison, it doesn't cause soreness and in fact it's something that your body loves to use as fuel.” He adds that lactate benefits your heart, brain, and kidneys.