Skin tags under your armpits are almost certainly caused by skin rubbing against skin. The armpit is one of the most common locations for these small, soft growths because the skin there folds and creases with every arm movement. Nearly 46% of the general population develops skin tags at some point, and that number climbs to about 59% by age 70. They’re harmless, but their appearance in your armpits can tell you something useful about your body.
Why the Armpit Is a Hot Spot
Skin tags are small pouches of collagen and blood vessels wrapped in skin. They form in areas where skin repeatedly rubs against itself or against clothing. Your armpits check both boxes: the skin there folds tightly, and it’s in near-constant motion throughout the day. That repeated friction irritates the top layer of skin and triggers the underlying connective tissue to bunch up into a small, soft projection, usually attached by a thin stalk.
Other friction-prone areas like the neck, groin, under the breasts, and along the eyelids are similarly common sites. If you notice skin tags in your armpits, you may eventually notice them in these other spots too.
Weight, Insulin, and Skin Tags
Friction explains where skin tags form, but it doesn’t fully explain why some people get many of them while others get none. Body weight plays a measurable role. In one study comparing people with and without skin tags, those with skin tags had an average BMI of 28.1 (overweight range), compared to 24.1 (normal range) in the control group. Higher body weight creates deeper skin folds and more surface contact, which means more friction.
There’s also a metabolic connection that goes beyond friction alone. Multiple studies have found that people with numerous skin tags are at higher risk of type 2 diabetes. A 2007 study found the link was strong enough to recommend that doctors screen for diabetes when a patient presents with multiple skin tags, and a 2015 study reinforced that conclusion. The connection appears to involve insulin resistance, a condition where the body produces excess insulin because cells aren’t responding to it efficiently. Elevated insulin levels may stimulate skin cell growth in ways that promote tag formation, though the exact mechanism isn’t fully understood.
This doesn’t mean your skin tags are a diabetes diagnosis. But if you’re developing clusters of them, especially alongside other risk factors like weight gain, fatigue, or increased thirst, it’s worth mentioning to your doctor.
Other Factors That Increase Your Risk
Genetics matter. If your parents developed skin tags, you’re more likely to get them too. This inherited tendency can mean that even people at a healthy weight with no metabolic issues still develop them, particularly in high-friction zones like the armpits.
Age is another consistent factor. Skin tags rarely appear in children and become increasingly common from your 30s onward. Hormonal changes during pregnancy can also trigger them, likely due to a combination of weight fluctuation, increased blood volume, and shifts in growth factors. They sometimes resolve after delivery but often remain.
How to Tell It’s Actually a Skin Tag
A skin tag is soft, flesh-colored, and hangs from the skin by a narrow stalk. It moves freely when you touch it and doesn’t hurt unless something snags on it. They range from a couple of millimeters to about the size of a grape, though most stay small.
Warts look and feel different. They’re firm, rough, and have a grainy texture. They tend to appear on areas of broken skin rather than skin folds, and they’re caused by a virus, which skin tags are not. Moles are flat or slightly raised, have defined borders, and are rooted more deeply in the skin rather than dangling from a stalk. If a growth under your arm is hard, rough, changing color, painful, or bleeding on its own, it’s worth having a dermatologist look at it.
Removal Options
Skin tags don’t need to be removed for medical reasons. They’re benign and won’t become cancerous. But if they’re irritating, catching on clothing or jewelry, or simply bothering you cosmetically, removal is straightforward.
A dermatologist can remove skin tags in a brief office visit using one of a few methods: snipping them off with surgical scissors, freezing them with liquid nitrogen, or burning the base with a small electrical current. The procedure is quick and usually requires only local numbing. Most removal wounds heal within one to three weeks depending on size and method. If stitches are placed, they’re typically removed within 5 to 14 days, though dissolvable stitches disappear on their own. Laser removal is also an option, though it may cause temporary skin color changes in the treated area.
Home removal kits exist, but the armpit’s sensitive, hard-to-see location makes self-treatment tricky. Tying off a skin tag with thread or dental floss (a method called ligation) cuts off blood supply and causes it to fall off in a few days, but infection risk increases when you can’t clearly see what you’re doing or keep the area clean.
Can You Prevent New Ones?
You can reduce friction in your armpits by keeping the skin dry, wearing moisture-wicking fabrics, and applying a light powder or anti-chafing balm. Maintaining a healthy weight also reduces the depth of skin folds and may lower your overall risk. If insulin resistance is contributing, managing blood sugar through diet, exercise, or medication can slow the development of new tags.
That said, if you’re genetically predisposed and getting older, some skin tags are simply inevitable. Removing them doesn’t prevent new ones from forming in the same area, so the goal is reducing the conditions that encourage them rather than expecting to eliminate them entirely.