Skin tags form when the body produces extra cells in the skin’s top layers, creating small, soft growths that hang from the surface by a thin stalk. The process is driven by a combination of friction, hormonal signals, and metabolic factors that trigger overgrowth of both the outer skin cells and the connective tissue beneath them. Most skin tags are completely harmless, but understanding why they appear can reveal useful information about what’s happening inside your body.
Friction and Skin Folds
The most straightforward cause is mechanical: skin rubbing against skin. Skin tags cluster in areas where folds create constant contact. The neck, armpits, groin, under the breasts, and eyelids are the most common sites. This repeated irritation triggers local immune cells to release chemical signals that promote tissue growth. Over time, a small nub of skin pushes outward and forms the characteristic dangling shape.
This is why skin tags tend to grow larger if left alone in high-friction zones. Clothing, jewelry, and skin folds continue to irritate the growth, encouraging it to expand. Tight or synthetic fabrics can make the problem worse, and necklaces or chains around the neck are a frequent aggravator. Friction alone can explain why even lean, otherwise healthy people develop the occasional skin tag.
Insulin Resistance and Metabolic Health
The more revealing cause is metabolic. Skin tags have a strong, well-documented link to insulin resistance, the condition where your cells stop responding efficiently to insulin and your pancreas compensates by pumping out more of it. That excess insulin sets off a chain reaction: it raises levels of a growth-promoting hormone called IGF-1, which directly stimulates skin cells to multiply faster than normal and pushes connective tissue cells to produce extra collagen. At the same time, high IGF-1 suppresses a protein that normally keeps cell growth in check. The result is a small, benign overgrowth of skin.
Research from Eastern India comparing people with and without skin tags found striking metabolic differences. People with skin tags had significantly larger waist circumferences (averaging 108 cm versus 94 cm in controls), higher triglycerides, and lower levels of HDL (the protective form of cholesterol). After accounting for all variables, the two strongest independent predictors of skin tags were a large waist circumference and low HDL cholesterol. Average BMI in the skin tag group was about 29, compared to 26 in controls.
This connection is important because skin tags can serve as a visible, early signal that your metabolism is shifting. Multiple skin tags, especially appearing in clusters, may point toward insulin resistance, prediabetes, or metabolic syndrome before those conditions show up on routine blood work. If you’re noticing new skin tags and also carrying extra weight around your midsection, it’s worth having your blood sugar and lipid levels checked.
Hormonal Changes
Hormones play a direct role in skin tag development. Elevated estrogen and progesterone stimulate the same cell-growth pathways that insulin does, which is why pregnancy is one of the most common triggers. The combination of rising hormone levels and increased skin friction (as the body changes shape) makes the second and third trimesters a peak time for new skin tags. Many of these shrink or disappear after delivery as hormone levels normalize.
Growth hormone excess also promotes skin tags. People with acromegaly, a condition where the pituitary gland overproduces growth hormone, develop them at unusually high rates. This reinforces the broader pattern: any condition that floods the body with growth-promoting signals can push skin cells past their normal turnover rate and produce these benign outgrowths.
The Role of HPV
One surprising contributor is the human papillomavirus. A study using highly sensitive DNA detection methods found HPV types 6 and 11 in nearly 49% of skin tag samples. These are low-risk strains of HPV (not the types linked to cancer), but their presence in such a large proportion of skin tags suggests the virus may play a role in triggering the abnormal cell growth. HPV is extremely common in the general population, and this finding expands the known range of benign skin conditions the virus can influence. Not every skin tag contains HPV, so the virus is likely one contributing factor among several rather than a standalone cause.
Genetics and Family History
Some people are simply more prone to skin tags than others, regardless of weight or hormonal status. A genetic component exists, though it’s not as clearly mapped as other inherited skin conditions. Skin tags were originally described as a feature of a rare genetic syndrome called Birt-Hogg-Dubé, but they turned out to be so common in the general population that they aren’t useful for diagnosing that condition. Still, if your parents or siblings develop skin tags easily, you’re more likely to as well. This genetic predisposition probably relates to individual differences in how your skin cells respond to friction and growth signals.
What’s Actually Happening Inside a Skin Tag
Under a microscope, a skin tag shows a thickened outer layer of skin arranged in finger-like projections. Beneath that, the interior contains loosely packed collagen fibers, tiny blood vessels, and lymphatic channels. This structure explains why skin tags can sometimes bleed when snagged or twisted: they have their own blood supply, even though they’re small. The tissue itself is entirely benign. There’s no risk of a skin tag turning into skin cancer.
The growth process involves two cell types working in tandem. The outer skin cells (keratinocytes) multiply more than usual, while the connective tissue cells (fibroblasts) beneath them produce excess collagen and structural material. Both of these cell types are responsive to insulin, IGF-1, estrogen, and the growth factors released by friction-related irritation, which is why so many different causes can produce the same result.
Why Some People Get Many and Others Get None
Skin tag development is cumulative. Each individual cause raises your baseline risk a little, and they stack. A person who is genetically predisposed, carries extra abdominal weight, and wears a chain necklace daily is far more likely to develop multiple skin tags than someone with just one of those factors. Age also matters: skin tags become more common after 40, likely because insulin sensitivity, hormone levels, and cumulative sun and friction exposure all shift over time.
If you’re developing new skin tags and want to slow the process, the most actionable steps target the modifiable causes. Reducing friction with loose-fitting clothing, avoiding jewelry in affected areas, and maintaining a healthy waist circumference all lower the growth signals that drive skin tag formation. For people whose skin tags are linked to insulin resistance, improvements in metabolic health (through diet, exercise, or weight loss) can reduce both the number of new tags and the rate at which existing ones grow.