Is excessive kissing harmful to your lips?

When did humans start kissing, and why did it become so popular? Some theories suggest it stems from the natural instinct to suckle, while others believe it evolved as a way for early humans to assess a potential partner's health through saliva [source: NPR]. Interestingly, not all cultures embrace kissing; around 10% avoid it, often due to hygiene concerns.

Kissing triggers a delightful physical response in humans. The brain releases oxytocin, a chemical that strengthens emotional bonds, and activates the reward center, producing dopamine, which creates feelings of pleasure. This reaction is similar to the effects of eating chocolate or using certain stimulants [source: Ahlstrom].

Kissing is a powerful emotional signal, expressing feelings of love, attraction, and affection. While it’s exhilarating, it’s not without risks. The herpes simplex virus 1 (HSV1), responsible for cold sores, can spread through kissing, as can syphilis. It’s also a potential route for transmitting certain sexually transmitted infections. Additionally, illnesses like mononucleosis, glandular fever (often called the kissing disease), colds, flu, and other infections can pass from one person to another through this intimate act.

This shouldn’t be shocking, especially to the 10% of cultures that avoid kissing. A single open-mouthed kiss can exchange approximately 250 bacterial colonies [source: Harrison]. The mouth harbors bacteria and saliva, which, though generally harmless, can irritate the delicate skin of your lips. On the next page, discover how kissing can not only spread diseases but also harm your lips.

How Kissing Could Damage Your Lips

The skin on your lips is quite distinct compared to the rest of your body. While the skin elsewhere has around 16 layers, the outermost layer, known as the stratum corneum, acts as a protective barrier. This layer consists of hardened, dead skin cells called corneocytes, which eventually shed and are replaced by new cells. On average, a person sheds approximately nine pounds (four kilograms) of dead skin cells annually [source: Reucroft, Swain].

In contrast, your lips are much thinner, comprising only three to five layers. Their delicate skin derives its color from the blood-rich capillaries in the underlying mucous membrane. This thinness leaves lips more vulnerable to damage, especially since they’re situated near the mouth, where saliva—rich in digestive enzymes like amylase and maltase—can break down their fragile surface every time you lick them [source: Gardner].

Kissing introduces even more saliva to the lips. Whether it’s a quick peck or a passionate, open-mouthed kiss (as studied by philematologists), saliva is transferred from one person to another. This constant exposure can harm the lips’ thin skin, as both your own saliva and your partner’s are spread across the surface.

Despite its potential to damage lips, saliva plays a crucial role in kissing. It carries hormones like testosterone, which enhances sexual desire and sensitivity in both men and women [source: Blackwell Publishing]. So, while kissing might pose risks to your lips, the benefits could make it worthwhile.