Skin tags form when several forces converge on the same patch of skin: repeated rubbing, metabolic signals driven by insulin resistance and obesity, genetic susceptibility, and hormonal changes. No single cause explains every skin tag. Friction tends to determine where they appear, while internal factors like blood sugar regulation and growth-factor signaling influence whether they appear at all. The interplay is what makes some people develop dozens of these small, fleshy growths and others never get a single one.
Friction and Where Skin Tags Show Up
The most visible clue to what drives skin tags is their location. They cluster in places where skin rubs against skin or clothing: the neck, armpits, under the breasts, eyelids, and the groin folds. This pattern has long pointed to mechanical friction as a trigger. One case report documented a patient who developed multiple skin tags arranged in a clear linear pattern along a friction line, strongly suggesting that repetitive rubbing played a direct role in their formation.1PubMed. Friction induced skin tags Tight necklines, bra straps, and belt lines are common culprits.
Friction alone, though, is not the whole story. Plenty of people experience chronic skin-on-skin rubbing without ever developing skin tags, and some individuals grow them in areas with minimal friction. Think of friction as the spark rather than the fuel. It creates the local irritation that, in someone whose metabolic and genetic background makes their skin cells more prone to overgrowth, tips the balance toward forming a tag.
Insulin Resistance and the Metabolic Engine
If friction explains where skin tags land, insulin resistance may be the most important explanation for why they form in the first place. When your body becomes less responsive to insulin, the pancreas compensates by pumping out more of it. That excess insulin drives up levels of a growth-promoting molecule called insulin-like growth factor 1, or IGF-1. In skin tissue, IGF-1 stimulates the outer layer of skin cells to multiply faster than normal, and it also suppresses the molecular brakes that would ordinarily keep that growth in check.2PubMed Central. The Correlation between Body Mass Index with the Occurrence of Skin Tag The result is a small mound of extra tissue that pushes outward from the skin surface.
Research on excised skin tags backs this up at the tissue level. When researchers stained skin tag samples for IGF-1 and compared them with normal skin, the tags showed significantly stronger IGF-1 activity in both the epidermis and deeper structures like fibroblasts and blood vessel cells.3PubMed Central. Role of insulin-like growth factor-1 in skin tags: a clinical, genetic and immunohistochemical study in a sample of Egyptian patients The same study found that certain gene variants affecting IGF-1 were more common in people with skin tags, hinting that your genetic makeup can amplify or dampen this growth-factor pathway.
The Link to Diabetes and Blood Sugar
Because insulin resistance is the metabolic precursor to type 2 diabetes, it follows that skin tags show up more often in people with diabetes or impaired glucose control. One case-control study found that people with skin tags had a much higher rate of diabetes than matched controls without tags, and that fasting blood sugar levels correlated positively with the total number of tags a person carried. People who had more than 30 skin tags were at particularly elevated risk: over half of that subgroup turned out to be diabetic.4PubMed. Skin tag as a cutaneous marker for impaired carbohydrate metabolism: a case-control study
Not every study finds the link to be this dramatic. A separate evaluation of over 500 people found that while skin tags were slightly more common in diabetic patients than non-diabetic ones, the difference was not statistically significant.5PubMed Central. A Clinical Evaluation of Skin Tags in Relation to Obesity, Type 2 Diabetis Mellitus, Age, and Sex This inconsistency likely reflects the fact that diabetes itself is not the cause; insulin resistance is. A person can have significant insulin resistance long before their blood sugar crosses the diagnostic threshold for diabetes. Skin tags may be acting as an early visible signal rather than appearing only after a diabetes diagnosis.
Obesity and Body Composition
Obesity overlaps heavily with both friction and insulin resistance, making it hard to tease apart its independent contribution. Heavier people have more skin folds, which means more friction. They also tend to have higher circulating insulin levels. Studies consistently find that people with skin tags have significantly higher body mass index and waist circumference compared with controls.6International Journal of Dermatology and Clinical Research. Metabolic Associations with Skin Tags But which matters more, the mechanical rubbing or the metabolic environment? Probably both at once. Weight loss reduces friction in skin folds and improves insulin sensitivity simultaneously, which may explain why some people notice their skin tags stop appearing after they lose weight, even though the old ones remain.
Genetic Susceptibility
Some families seem especially prone to skin tags regardless of weight or metabolic status. Dermatologists have long noted a familial clustering that suggests a heritable component. Genetic research is still early, but it has begun to identify specific variants that differ between people with and without tags. A study examining the CDH1 gene, which codes for a cell-adhesion protein involved in how skin cells stick together, found that certain genotype distributions at two locations in this gene were significantly different between skin tag patients and controls.7Meta Gene. Are the genetic variants/haplotypes of the CDH1 gene contribute to skin tags and internal malignancies in skin tag subjects? A pilot study Because CDH1 plays a role in cell-to-cell adhesion and growth regulation, variants that alter its function could make the skin more susceptible to the outward bulging that forms a tag.
Gene variants affecting IGF-1 activity add another genetic layer. As mentioned earlier, specific polymorphisms in the IGF-1 gene were more prevalent in Egyptian patients with skin tags, and those variants appeared to influence how much IGF-1 was produced locally in skin tissue.3PubMed Central. Role of insulin-like growth factor-1 in skin tags: a clinical, genetic and immunohistochemical study in a sample of Egyptian patients These findings are from relatively small studies in specific populations, so they should not be read as definitive. But the direction of the evidence is consistent: genetics influence skin tag risk, probably by modulating the growth-factor and adhesion pathways that allow tags to form under the right conditions.
Hormonal Changes and Endocrine Conditions
Pregnancy is one of the best-known triggers for new skin tags. During pregnancy, estrogen and progesterone levels surge, growth factors circulate at higher levels, and weight gain increases friction in skin folds. Many women notice new tags on the neck and under the arms during the second and third trimesters. These sometimes shrink or fall off after delivery, though not always.
On the more extreme end of hormonal influence, acromegaly offers a revealing natural experiment. Acromegaly involves chronically elevated growth hormone and, in turn, high IGF-1 levels. A study of patients with acromegaly found that skin tags were the single most common skin finding, present in over half of patients.8PubMed. Cutaneous findings in patients with acromegaly and its relationship with concomitant endocrinopathies That frequency is strikingly higher than in the general population and makes intuitive sense given the growth-factor mechanism described above. When your body is flooded with growth signals, skin cells respond by proliferating, and skin tags are one visible consequence.
Does HPV Play a Role?
A more surprising hypothesis is that human papillomavirus might contribute to some skin tags. One study tested 37 skin tag samples and detected low-risk HPV types 6 and 11 in nearly half of them, while the normal skin immediately surrounding the tags was negative for HPV DNA.9PubMed. Human papillomavirus and skin tags: Is there any association? HPV types 6 and 11 are the same strains that cause common genital warts, and their ability to stimulate skin cell growth could theoretically help initiate a tag.
But the evidence is genuinely contradictory. A separate study using the same type of molecular testing found no HPV of any subtype in skin tag samples, while two control samples from people without tags actually tested positive for high-risk HPV.10PubMed Central. An Association of Human Papillomaviruses Low Risk and High Risk Subtypes with Skin Tag The discrepancy could reflect differences in patient populations, sampling methods, or laboratory sensitivity. At this point, most dermatologists do not consider HPV a primary driver of skin tags. It may contribute in a subset of cases, but the bulk of the evidence points to metabolic and mechanical causes as far more important.
Growth Factor Activity in Active Tags
Whatever starts a skin tag, what keeps it growing involves epidermal growth factor receptors. Researchers comparing actively growing skin tags with dormant ones found that the growing tags showed elevated levels of these receptors, while non-growing tags had patterns indistinguishable from normal skin.11PubMed Central. Epidermal growth factor receptors in idiopathic and virally induced skin diseases This finding suggests that skin tags are not a one-time event but an ongoing growth process that can stall or restart. The growth factor receptor activity correlates positively with active cell proliferation. Once the growth signals quiet down, the tag stops enlarging and simply hangs there.
This may explain the common observation that skin tags often seem to appear suddenly and then remain the same size for years. They are not really sudden; they grow over days or weeks when local growth factors are elevated, then stop. The perception of “sudden” comes from the fact that a tiny tag goes unnoticed until it reaches a size large enough to catch on jewelry or clothing.
Skin Tags as Markers of Metabolic Syndrome
Because skin tags are linked to insulin resistance, obesity, and elevated blood pressure individually, researchers have asked whether they correlate with metabolic syndrome as a whole. The answer, from a case-control study in eastern India, was striking: the relative risk of having metabolic syndrome was roughly eleven times higher in people with skin tags than in matched controls. The same group had higher waist circumference, higher blood triglycerides, lower HDL cholesterol, and more diabetes.12PubMed Central. Association of Skin Tag with Metabolic Syndrome and its Components: A Case–control Study from Eastern India A separate group’s metabolic profiling found that overweight, abnormal lipids, high blood pressure, insulin resistance, and elevated inflammatory markers were all more common in people with skin tags, leading them to suggest skin tags could flag increased atherosclerosis and cardiovascular risk.13PubMed. The metabolic profile in patients with skin tags
The lipid picture is not entirely clean, though. While one study found significantly higher total cholesterol and LDL in skin tag patients compared with controls,14PubMed Central. Serum Leptin, Atherogenic Lipids and Glucose Levels in Patients with Skin Tags another found no meaningful link between skin tags and abnormal lipids in an Iranian population, concluding that tags may not reliably indicate dyslipidemia or cardiovascular disease in that group.15PubMed Central. A comparison study of lipid profile levels between skin tags affected people and normal population in Tehran, Iran Population differences, diet, and study design all play a role in these discrepancies. The broader trend still holds: if you suddenly develop many skin tags, particularly after age 40, it is worth mentioning to your doctor, not because the tags themselves are dangerous but because they may be pointing toward metabolic conditions that are.
Age, Sex, and Who Gets Them
Skin tags are rare in children and become progressively more common through middle age. A study of 750 unselected people found that 46 percent carried at least one skin tag, with risk increasing steadily with age until around 50, after which the rate of new cases plateaued.16Dermatologica. Skin Tags: Localization and Frequencies According to Sex and Age Men were slightly more likely to have them than women in that sample, though other studies have found no clear sex difference once weight and metabolic factors are accounted for.
A hospital-based study reported a mean age of onset around 27 years, but the range was enormous, from teenagers to octogenarians. When skin tags appeared alongside other health conditions, they tended to show up later in life, be more numerous, and be larger. Those associated with multiple comorbidities were darker in color and more often the broad-based “sessile” type rather than the thin-stalked kind.17Journal of the Egyptian Women’s Dermatologic Society. Prevalence, clinical criteria, and risk factors of skin tags: a hospital-based study This observation fits the broader pattern: skin tags that are numerous, large, or appear later in life are more likely to be associated with metabolic problems, while isolated tags in young adults are more often just a friction-and-genetics story.
What a Skin Tag Actually Looks Like Inside
Under a microscope, a skin tag is a pretty simple structure. It consists of an outer layer of epidermis covering a core of loose connective tissue, often containing small blood vessels and collagen fibers. Researchers who examined 30 skin tags found three main shapes: furrowed (the majority), bag-like, and filiform, which is the thin thread-like type. All of them showed a consistent feature that healthy skin lacked: the elastic fibers running through the connective tissue were thinner and fewer in number compared with surrounding normal skin.18International Journal of Pathology and Clinical Research. Reduced and Thinned Elastic Fibers in Skin Tag
That loss of elastic fibers probably matters mechanically. Elastic fibers give skin its snap-back quality, keeping it taut and resilient. When those fibers are degraded or scarce in a localized area, the tissue becomes softer and more pliable, making it easier for a small bump to stretch outward into a pedunculated tag rather than being held flat against the body surface. Whether the elastic fiber loss comes first and predisposes the area to tag formation, or whether the tag’s abnormal growth degrades the fibers over time, is something the research has not fully sorted out yet. Either way, it helps explain why skin tags feel soft and floppy rather than firm.
When Skin Tags Are Not Skin Tags
Worth mentioning is that not every soft bump hanging off your skin is actually a skin tag. Several other growths can look similar at a glance. Seborrheic keratoses, which are rough, waxy-surfaced growths common in older adults, sometimes dangle from a narrow base and mimic the profile of a tag. Neurofibromas, soft bumps that arise from nerve tissue, can appear in skin folds and be virtually indistinguishable from tags without a biopsy. Warts occasionally form on stalks, especially in moist areas. And in rare cases, what looks like a harmless tag can turn out to be a small melanoma or basal cell carcinoma growing in an unusual shape.
Most skin tags never need to be removed for medical reasons. If a growth is painful, bleeds without being caught or rubbed, changes color rapidly, or feels hard rather than soft, those are signs it may not be a simple tag and should be evaluated by a dermatologist. Otherwise, removal is a cosmetic choice. The tags themselves carry no malignant potential and do not “turn into” cancer. The real clinical value in paying attention to them lies in what they signal about your metabolic health rather than anything dangerous about the tags themselves.