One large studyTrusted Source found that dozens of genetic factors may determine where you store fat. This study also found that fat accumulation and distribution in people with vulvas is more likely to be impacted by genetics than in people with penises.Losing weight by eating a nutritious diet and exercising can help reduce armpit fat. But studiesTrusted Source showTrusted Source that it’s hard to target or spot-reduce specific areas of the body.

Poor posture may not cause armpit fat, but can make it more apparent.

If you have a forward-rolling shoulder posture, standing up straight may help reduce the look of extra armpit skin.

  • Lose weight to help reduce armpit fat as well as fat stores throughout your body.
  • Build muscle mass in your chest wall and upper arms. Armpit fat can be resistant to exercise, including resistance or weight training specifically for that purpose. Building chest muscle mass and toning your upper arms can help tighten the area, reducing the look of armpit fat. Building muscle also burns calories, so it helps with weight loss.
  • Wear properly fitting undergarments. new bra can help reduce the appearance of armpit fat. Many people don’t realize they’re wearing tight undergarments that can push the skin and fat around the sides of your breast upward.