Skin tags form when friction, hormones, and metabolic factors cause skin cells to overgrow in areas where skin rubs against itself or clothing. Nearly 46% of adults over 40 have at least one, making them one of the most common benign skin growths. They appear as small, soft pouches of skin hanging from a narrow stalk, and while they’re harmless, the reasons behind them reveal useful information about what’s happening inside your body.
Friction Is the Primary Trigger
The most direct cause of skin tags is repeated rubbing. Skin-on-skin contact or skin-on-clothing contact irritates the outer layer of skin over time, prompting a small overgrowth of tissue. That’s why skin tags cluster in very specific spots: the sides of the neck, the armpits, the groin, and the eyelids. These are all areas where skin naturally folds and rubs throughout the day.
Jewelry is a common culprit around the neck. Necklaces and chains create constant low-grade friction that can trigger new growths or enlarge existing ones. Bra straps, waistbands, and underwear elastic do the same in other areas. Once a skin tag forms, continued friction from clothing or skin folds can cause it to grow larger over time.
Insulin and Blood Sugar Play a Bigger Role Than Most People Realize
Friction explains where skin tags show up, but it doesn’t fully explain why some people get dozens while others get none. The answer often involves insulin. When your body produces excess insulin, a hallmark of insulin resistance and type 2 diabetes, that insulin activates growth-factor receptors on the surface of skin cells. Specifically, high insulin levels trigger receptors that tell both the outer skin cells (keratinocytes) and the connective tissue cells underneath (fibroblasts) to multiply faster than normal. This overgrowth is what produces the extra tissue that becomes a skin tag.
The connection is strong enough that skin tags are considered a visible marker for metabolic problems. A case-control study from Eastern India found that people with skin tags were over 11 times more likely to have metabolic syndrome, a cluster of conditions including insulin resistance, high blood pressure, high triglycerides, and low levels of protective cholesterol. The two metabolic factors most strongly linked to skin tags were a larger waist circumference and low HDL (“good”) cholesterol. If you’re noticing new skin tags appearing frequently, it may be worth having your blood sugar and cholesterol checked.
Hormonal Changes During Pregnancy
Many women notice skin tags appearing for the first time during pregnancy. Fluctuations in estrogen and progesterone stimulate skin cell growth, and the combination of hormonal shifts with the increased skin friction that comes from weight gain makes pregnancy a perfect storm for skin tag development. These tags often appear in the second and third trimesters and may stop growing after delivery, though they typically don’t disappear on their own.
Weight and Body Composition
Carrying extra weight increases skin tag risk through two separate pathways. First, more body mass means more skin folds, which means more friction in more places. Second, excess weight, particularly around the midsection, is closely tied to insulin resistance. So the mechanical trigger and the metabolic trigger reinforce each other. This is why weight loss sometimes slows or stops the appearance of new skin tags, even though it won’t shrink the ones already there.
Age and Genetics
Skin tags become increasingly common with age. They’re rare in children and young adults, and prevalence climbs steadily after 30, with the highest rates in people over 40. Part of this is simply accumulated exposure to friction and the metabolic changes that come with aging, but genetics also play a role. Skin tags tend to run in families, and if your parents developed them, you’re more likely to as well. In rare cases, widespread skin tag-like growths are associated with specific inherited genetic conditions, though this is uncommon.
A Possible Viral Connection
Some researchers have investigated whether certain strains of the human papillomavirus (HPV) contribute to skin tag formation. One study found HPV types 6 and 11 in 88% of skin tag samples, while another found them in 77% of samples. However, a separate study only detected the virus in about half of samples and found no clear relationship between HPV and skin tag development. The results are inconsistent enough that HPV is not considered a proven cause. It may be present in skin tags without actually driving their growth.
What Skin Tags Can Tell You About Your Health
Most skin tags are nothing more than a cosmetic nuisance. But their presence, especially in large numbers, can be a useful early signal. The link between skin tags and metabolic syndrome means that a sudden crop of new tags, particularly alongside weight gain around the waist, could point toward insulin resistance developing before blood sugar levels are high enough to trigger a diabetes diagnosis. In this sense, skin tags function as an external clue about internal metabolic health. People with diabetes, high blood pressure, or abnormal cholesterol levels develop skin tags at significantly higher rates than the general population.
Skin tags don’t become cancerous and don’t need to be removed for medical reasons. But if they’re irritated by clothing, catch on jewelry, or bother you cosmetically, a dermatologist can remove them quickly with freezing, a small snip, or a mild electrical current. They won’t grow back in the same spot, though new ones can form nearby if the underlying causes, friction, hormones, or insulin levels, remain unchanged.