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.

More friction means a higher chance of small skin growths forming. Areas like the neck, underarms, and inner thighs are particularly common locations for skin tags in people who are overweight.

Maintaining a healthy weight may reduce some of the conditions that contribute to their formation, though it does not always prevent them entirely.

5. Insulin Resistance
Some research suggests that skin tags may be associated with insulin resistance. Insulin resistance occurs when the body has difficulty using insulin effectively, which can sometimes be linked to metabolic conditions.

People who develop multiple skin tags—especially around the neck or underarms—may occasionally be advised by doctors to check their blood sugar levels. While skin tags themselves are not dangerous, they can sometimes appear more often in people with metabolic changes.

6. Genetics
Finally, genetics can play a significant role. If your parents or close relatives have skin tags, you may be more likely to develop them as well.

Some people simply have a genetic tendency toward these harmless skin growths. In these cases, skin tags may appear even without significant friction, weight changes, or hormonal shifts.

When to See a Dermatologist
Most skin tags are harmless and do not require treatment. However, it may be a good idea to consult a dermatologist if a growth changes color, grows quickly, becomes painful, or starts bleeding.

A medical professional can confirm whether the growth is a skin tag or another type of skin condition and recommend safe removal options if necessary.

In most cases, skin tags are simply a normal part of how skin changes over time. While they may appear suddenly, they are usually the result of everyday factors such as friction, hormones, and genetics. Understanding these causes can make them much less mysterious—and much less worrying.