Tears caused by a speck of dust in the eye are not the same as tears of emotion.
You already know that. In the first case, they only produce a wet feeling in the cheek; in the second, they remove the entrails.
This is because their chemical composition is different, since tears of emotion contain more proteins, hormones and other molecules that have an effect on the body.
Healthy Tears and Bitter Tears:
Tears of emotion are usually healthy, because they contain leucine encephaline, a hormone that acts on pain, as well as the stress molecules and toxins that the body excretes when it cries. Also, the nervous message of the tears causes the production of natural analgesics (pain suppressants). One study has estimated that crying reduces sadness or anger by about 40%.
However, not all tears of emotion are relieved. According to a study of 200 women in the Netherlands, people suffering from depression or anxiety feel even worse after crying.
Women and Tears:
Women cry on average four times as much as men after puberty. This is related to the production of some hormones such as prolactin, which is responsible for breastfeeding after childbirth, absence of ovulation and tearing up.
After giving birth, the prolactin level increases even more, which explains why young mothers may have easy tears. In contrast, after age 40, the prolactin level decreases and women stop crying more than men.
By @edyazoimar