Skin tags grow when a combination of friction, hormonal signals, and metabolic factors triggers an overgrowth of skin cells. Most skin tags stay small, between 1 and 5 mm, though they can occasionally reach 1 to 2 cm if irritation continues. Understanding what drives their growth can help you figure out why you’re getting them and whether they signal something worth paying attention to.
Friction Is the Most Direct Trigger
Skin tags almost always appear where skin rubs against skin or clothing. The neck, armpits, groin, and eyelids are the most common locations, all areas where folds of skin create constant low-grade irritation. This repeated mechanical friction is thought to stimulate the outer and deeper layers of skin to overproduce cells, eventually forming a small, soft growth on a narrow stalk.
Once a skin tag forms, ongoing friction can make it larger. Necklaces, tight collars, and restrictive or synthetic clothing all increase irritation around existing tags, sometimes causing them to bleed or itch. If you’ve noticed skin tags growing bigger over time, the simplest explanation is that something keeps rubbing against them. Avoiding tight jewelry around the neck and choosing looser, breathable fabrics can slow that process.
High Insulin Levels Drive Cell Overgrowth
The strongest metabolic link to skin tags is insulin resistance. When your body produces excess insulin to manage blood sugar, that extra insulin activates growth-factor receptors on two key cell types in your skin: the cells that form the outer surface (keratinocytes) and the structural cells deeper in the skin (fibroblasts). Insulin essentially mimics a growth signal, telling these cells to multiply faster than they normally would. The result is a small, benign overgrowth of tissue.
This connection is well documented. A study from eastern India found that the risk of having metabolic syndrome was more than 11 times higher in people with skin tags compared to people without them. People with skin tags in that study also had significantly higher cholesterol, higher triglycerides, and lower levels of HDL (the “good” cholesterol). Higher blood pressure was also more common in the skin tag group. None of this means a skin tag is dangerous on its own, but a sudden crop of new skin tags, especially in your 30s or 40s, can be a visible signal that your blood sugar and metabolic health deserve a closer look.
Body Weight and BMI
Obesity and skin tags are closely linked, and the relationship works through both of the mechanisms above. More body weight typically means more skin folds and more friction. It also increases the likelihood of insulin resistance.
Research comparing people with and without skin tags found that the average BMI in the skin tag group was 28.1 (overweight range) compared to 24.1 (normal range) in the control group. That’s a statistically significant gap. People in the overweight and obese BMI categories simply have a higher predisposition to developing skin tags, and losing weight often reduces the rate at which new ones appear.
Hormonal Changes During Pregnancy
Many women notice new skin tags during pregnancy, particularly in the second and third trimesters. Two factors converge: rising levels of estrogen and progesterone stimulate skin cell growth, and weight gain creates new areas of friction. Skin tags that appear during pregnancy sometimes shrink or fall off after delivery as hormone levels normalize, though not always.
Genetics Play a Role
Some people are simply more prone to skin tags than others, regardless of weight or metabolic health. Family history matters. There is even a rare inherited condition called Birt-Hogg-Dubé syndrome, caused by a mutation in the FLCN gene, that produces skin tags along with other skin and kidney findings. That syndrome is uncommon, but the broader point holds: if your parents had skin tags, you’re more likely to develop them too.
The HPV Connection
Several studies have found DNA from certain strains of human papillomavirus (HPV), specifically types 6 and 11, inside skin tag tissue. One study detected HPV DNA in 88% of skin tags tested; another found it in 77%. However, not all research has confirmed a direct cause-and-effect relationship. HPV types 6 and 11 are the same low-risk strains associated with common warts, not the high-risk strains linked to cancer. Whether the virus actively causes skin tags or is simply present in the tissue remains an open question.
How to Tell Skin Tags From Similar Growths
Skin tags are soft, skin-toned or slightly brown, and hang from the skin on a thin stalk. Their surface is usually smooth. That stalk is the easiest way to distinguish them from other common growths:
- Warts have a rough, scaly surface and sit flat or slightly raised on the skin. Filiform warts can look elongated and stalk-like, making them the hardest to tell apart from skin tags, but their texture is noticeably rougher.
- Moles are flat or dome-shaped, usually round or oval, and sit flush against the skin without a stalk. They often have darker pigmentation and may contain tiny hairs.
A skin tag that changes color, becomes painful without being snagged, or grows rapidly beyond a centimeter or so is worth having evaluated, since those features are unusual for a straightforward skin tag.
Why They Keep Coming Back
Removing a skin tag doesn’t prevent new ones from forming. The underlying drivers, whether friction, insulin resistance, hormonal shifts, or genetics, are still present. People who develop skin tags in one area often develop them in other friction-prone spots over time. Addressing the root causes, particularly maintaining a healthy weight and managing blood sugar, is the most effective way to reduce how many new tags appear. Wearing smooth, well-fitting clothing and minimizing jewelry in areas where tags tend to form can also help keep friction-related growth in check.