Skin tags are small, soft growths that hang off the skin. They are usually flesh-colored or slightly darker and can appear almost anywhere on the body. Although they may look unusual, skin tags are extremely common and generally harmless. Many people first notice them in adulthood, often wondering why they seemed to appear “overnight.”

Dermatologists explain that skin tags rarely develop for a single reason. Instead, they tend to appear due to a combination of physical, hormonal, and genetic factors. Understanding these causes can help you better recognize why they form and when they may become more noticeable.

1. Skin Friction

One of the most common causes of skin tags is simple friction. When skin repeatedly rubs against other skin or clothing, small growths can develop over time. This is why skin tags often appear in areas such as the neck, underarms, groin, or under the breasts.

The repeated irritation can stimulate skin cells to grow outward, forming the small, soft projections we call skin tags. People who wear tight clothing or have natural skin folds may be more likely to develop them.

2. Aging

Skin tags tend to become more common as people get older. While they can appear at almost any age, many adults start noticing them in their 40s or 50s.

As the skin ages, its structure changes and becomes more prone to developing small benign growths. Collagen and elastin fibers shift over time, and the skin may respond differently to friction and minor irritation. This natural aging process can increase the likelihood of skin tags appearing.

3. Hormonal Changes

Hormonal shifts can also play a role in the formation of skin tags. Many women notice new skin tags during pregnancy, when hormone levels change significantly.

Hormones influence how skin cells grow and repair themselves. When these levels fluctuate, the skin may respond by forming small growths in areas prone to friction. These skin tags are usually harmless and may stop appearing once hormone levels stabilize.

4. Being Overweight

People who carry extra body weight may develop skin tags more frequently. This is partly because additional skin folds increase friction between skin surfaces.