If you have flabby underarms, also called shopping bag arms, Mrs. Jiggles, or flappers, you can do a few exercises to tighten the skin. Keep in mind, however, that no feasible amount of exercise will get rid of fat if you don't watch your diet and nutrition. While experts say you can't necessarily target weight loss to a certain part of your body, you can tone muscles in particular areas with exercise.
Start off with some tricep extensions. Sit with your best posture on a bench or in a chair. Grab a dumbbell with both hands clasped around it. Raise the dumbbell over your head and then tuck your upper arms against your ears as you lower the dumbbell behind your head. Your elbows should point to the ceiling. Using your elbows as hinges, lift your arms straight up and then lower the dumbbell back down. Repeat eight times.
Add tricep kickbacks to your routine. Stand and place the dumbbell in one hand. Lean over and, with the other hand, brace your body's weight on the outer edge of the chair or bench. Bring the arm with the dumbbell straight back, parallel with the floor, with the palm facing the ceiling. Allow your elbow to act as a hinge and the upper arm to drop down. With controlled movements, bring your arm back up. Repeat eight times to both sides.
Try some tricep push-ups. Make sure your bench or chair is stable, as you will be working with your own body weight while you lean against the edge. Sit on the edge of the chair or bench and place you hands beside your hips, on the edge of the bench or chair. Your knees should be bent and your feet about two feet from the edge of the chair or bench. Push yourself off the edge of the bench or chair and slowly lower your upper body to the floor and then up, but do not sit down until your eight repetitions are completed. To add more of a challenge, extend your legs out straight.
Finish your workout with some tricep underarm tighteners. At first, try this without the weights. Stand with your arms straight out at your sides. Rotate your hands so that your thumbs point behind you, but be sure not to tense your shoulders. Draw your arms behind you so the thumbs point to one another and raise your arms as high as you can. Bend your knees slightly to protect your back and lean forward about 30 degrees. With a small movement (you should really feel this) bring your arms one or two inches closer and relax, closer and relax. Work up to 100 of these small movements.