A number of factors, including weight fluctuation, age, and genetics can cause your upper arms to droop or sag.
You may have improved the underlying muscle tone of your upper arm, but exercise will not help the extra skin that has lost its elasticity, underlying weakened tissues or localized fat deposits. An arm lift can:
Reduce excess skin and fat between the underarm and the elbow.
Reshape your arm to result in smoother skin and contours.
Result in a more toned and proportionate appearance.