Biology of Tears: Why Crying is a Chemical Reset

While humans are not the only animals that shed tears to lubricate their eyes, we are the only species known to cry emotional tears. For decades, science viewed crying merely as a social signal of distress. However, biochemical analysis reveals that crying is an essential excretory function that physically purges stress from the body.

The Three Types of Tears

The human body produces three distinct types of tears:

1. Basal Tears: Constant lubrication that protects the cornea.
2. Reflex Tears: Flushing tears triggered by irritants like smoke or chopped onions.
3. Emotional Tears: Triggered by intense sadness, joy, or frustration.

The Chemical Composition of Emotion

In the 1980s, biochemist Dr. William Frey discovered that emotional tears have a vastly different chemical makeup than reflex tears. Emotional tears contain significantly higher levels of adrenocorticotropic hormone (ACTH)—a chemical linked to stress. They also contain higher levels of prolactin and leucine enkephalin, an endorphin that reduces pain and improves mood.

When we experience intense emotional stress, our neuroendocrine system goes into overdrive. Emotional crying acts as a pressure release valve. By literally excreting these stress hormones and neurotoxins through our tear ducts, the body rapidly restores homeostasis.

This biochemical purge is the reason why we often feel physically lighter and more clear-headed after a "good cry." It is not just an emotional release; it is a physiological detoxification.