In the 1970s, Dr. William Frey, a professor of pharmaceutics at the University of Minnesota, analyzed the chemical makeup of reflexive tears (the kind you cry when you cut up an onion) versus emotional tears (the kind you cry while watching a sad movie). What he found was fascinating. While reflexive tears generally serve to protect the eyes by flushing and lubricating them, Frey postulated that the main function of emotional tears is to help the body recover from a stressful event by excreting excess hormones and other proteins.
When we experience stress, a substance called adrenocorticotropic hormone (ACTH) is released into our bodies. If enough of ACTH builds up, it will eventually stimulate the release of cortisol, also known as "the stress hormone."
The neat thing that Dr. Frey found was that tears act to rid the body of these excess stress hormones. After a good cry, most people feel calmer and more resilient since their tears literally just drained stress hormones from their bodies. More tears = less ACTH = less stress. How cool is that?!
Crying can also protect you from getting sick. All tears contain lysozyme, a natural antibacterial substance that can destroy up to 95 percent of bacteria that come in contact with our eyes within 10 minutes. So when your eyes are welling up, they're also washing up.
Emotional tears also contain leucine-enkephalin, an endorphin responsible for reducing pain and improving mood. So crying literally making you feel better by releasing natural painkillers!