Skin tags form when repeated friction causes the body to produce extra cells in the skin’s top layers. But friction alone doesn’t explain the full picture. Hormonal shifts, insulin levels, genetics, and possibly even certain viruses all play a role in why some people develop dozens of skin tags while others never get a single one.
How Friction Triggers Skin Tags
The most immediate cause is mechanical: skin rubbing against skin. That’s why skin tags cluster in predictable spots like the armpits, neck, eyelids, groin, under the breasts, and along the thighs. These are all areas where natural movement creates constant low-grade irritation. Jewelry and tight clothing can contribute too, adding another source of repeated rubbing.
When skin in these folds gets irritated over and over, the body responds by growing a small pouch of tissue. Structurally, a skin tag is a core of loosely arranged connective tissue covered by a layer of normal-looking skin. The elastic fibers inside tend to be thinner and fewer than in surrounding skin, which is why tags feel soft and often dangle on a narrow stalk. Larger ones can develop a center of fatty tissue.
The Insulin Connection
Friction explains where skin tags appear, but metabolic health often determines how many you get. The link between skin tags and insulin resistance is one of the strongest in dermatology. In one study from South India, 65% of people with skin tags met the criteria for metabolic syndrome, compared to 28% of people without them.
The mechanism works like this: when your body becomes resistant to insulin, it compensates by producing more of it. That excess insulin boosts levels of a growth signal called insulin-like growth factor 1, or IGF-1. IGF-1 directly stimulates two types of cells to multiply. Keratinocytes, the cells that form the outer layer of skin, start overproducing and thicken the surface. Fibroblasts, the cells that build connective tissue underneath, proliferate and lay down extra structural material. The result is a small mound of excess tissue that becomes a skin tag.
This is why skin tags are sometimes considered a visible marker of deeper metabolic problems. Studies have found significant associations between skin tags and high blood pressure, elevated fasting blood sugar, low HDL cholesterol, and even coronary artery disease. If you’ve noticed a sudden increase in skin tags, especially if you’re also carrying extra weight around your midsection, it can be worth mentioning to your doctor as a reason to check your blood sugar and cholesterol levels.
Why Pregnancy and Weight Gain Matter
Many people notice new skin tags during pregnancy, and the explanation involves more than just the physical changes in body shape. Pregnancy raises levels of a hormone called leptin, which is also elevated in obesity and diabetes. Leptin stimulates blood vessel growth and triggers cell multiplication in both keratinocytes and fibroblasts, the same two cell types involved in the insulin pathway. Research published in the Indian Journal of Dermatology found that leptin levels were actually higher in small, newly forming skin tags than in larger, more established ones, suggesting leptin is most active during the early growth phase.
Weight gain outside of pregnancy has a similar effect. Obesity increases both friction (more skin folds) and the metabolic drivers (higher insulin, more leptin) at the same time. That combination makes skin tags far more common in people with a higher body mass index.
Genetics and Family History
If your parents or siblings have skin tags, you’re more likely to develop them too. One study found a statistically significant association between having skin tags and having a family history of them. Researchers have identified specific genetic variants in a gene called CDH1 that appear more frequently in people with skin tags. This gene is involved in how skin cells stick together and communicate, and certain mutations in it may make the skin more prone to forming these growths. The genetic piece helps explain why some thin, metabolically healthy people still develop skin tags: their cells may simply be predisposed to respond more aggressively to minor friction or hormonal signals.
A Possible Viral Link
One of the more surprising findings in skin tag research involves human papillomavirus, or HPV. A study of 37 skin tag samples found HPV types 6 and 11 in nearly half of them (48.6%), while surrounding normal skin tested completely negative. An earlier study in European patients found HPV in 88% of skin tags tested. These are low-risk HPV strains, the same types associated with common warts rather than cancer. The presence of HPV doesn’t necessarily mean the virus causes skin tags, but it suggests the virus may be a contributing factor in some cases, potentially triggering the cell overgrowth that forms the tag.
What Skin Tags Can Tell You About Your Health
Skin tags themselves are harmless. They’re not cancerous and don’t become cancerous. But their presence, especially in large numbers, can signal metabolic changes worth paying attention to. People with multiple skin tags are significantly more likely to have insulin resistance, type 2 diabetes, high blood pressure, and unfavorable cholesterol levels. The more skin tags a person has, and the later in life they first appear, the more likely it is that multiple metabolic conditions are present at the same time.
A few skin tags in areas of high friction, like under a bra strap or along the neck where a necklace sits, are extremely common and rarely meaningful on their own. Roughly 30% of patients in hospital-based dermatology studies present with at least some skin tags. They become more frequent with age and are equally common in men and women. But a sudden crop of new tags, particularly if you’ve also gained weight or have a family history of diabetes, is worth treating as a useful signal rather than just a cosmetic annoyance.
Reducing Your Risk
Because skin tags grow from a combination of friction and internal metabolic signals, the most effective prevention targets both. Wearing clothing that doesn’t bunch or rub in skin folds helps reduce the mechanical trigger. Keeping skin dry in areas prone to moisture and friction, like the armpits and groin, also lowers the irritation that starts the process.
On the metabolic side, maintaining a healthy weight and stable blood sugar levels addresses the growth signals that drive skin tag formation. For people whose skin tags are linked to insulin resistance, improving insulin sensitivity through diet, exercise, or medical management often slows the appearance of new ones. Existing skin tags won’t shrink on their own, but the rate of new growth tends to decline when the underlying metabolic factors improve.