Choose your administration site - stomach (excluding a 2" radius around the navel), top or outer part of your thighs, or the back of your upper arms. Then use your thumb and forefinger to pinch up a fold of skin and hold steady as you make the injection into this fold of skin. Heparin should not be injected into a muscle, area close to a bone, in veins, or into the face or scalp. To avoid the risk of lipodystrophy, it is best to use a different site for each injection.