Over-the-counter drugs like Midol even claim to treat PMS symptoms like tension and irritability, even though they only contain a diuretic, a pain reliever and caffeine.
Alternatively, it can occur when the body's natural painkillers, neurotransmitters such as endorphins that dampen the flow of pain signals, are less readily manufactured.
All three contain salt, proteins, and antibacterial enzymes, but emotional tears have higher amounts of protein, including stress hormones and natural painkillers that we don't yet know the purpose of.