The first thin arm recipe: 1. Take a dumbbell or a bottle filled with water (or sand) and straighten it from front to back. Remember to do this next to your ear. 2. Put it down slowly and repeat this action fifteen times. When you finish, your upper arm will feel sour. That's right. Do it forty-five times a day, separately. The second secret recipe of thin arm: the right arm is extended high, the left scapula bends backward, the left hand presses the joint of the right arm, touches the left scapula, then extends high, and changes sides. This action is done 20 times a day. If you feel sore from the beginning, it means you have moved to that part. The third measure of thin arms: 1. Stand with your hands straight forward and your feet shoulder width apart. 2. Draw a circle with both hands and draw a circle outward for 20 times. 3. Draw a circle inward 20 times. 4. Don't draw too big a circle, use the strength of your arm, not your palm. The fourth recipe for thin arms: 1. Stand up straight, spread your feet about shoulder width, spread your arms to both sides, and slowly turn forward. The point is to tighten the muscles on the upper arm. 2. Stand up straight, spread your feet about shoulder width, spread your arms to both sides, and turn around slowly. This is mainly to tighten the muscles of the arms and chest. Don't draw the circle too big, so as not to hurt the joints of your shoulders.