The breasts can be enlarged permanently by breast augmentation surgery to your desired size, depending of course on the available skin. The operation takes 2-3 hours, and the patient can go home the same day. Subsequently, breast-feeding is not affected, and ones personal life invariably improves significantly, as the breasts play an important role in your personal life. There are no side effects of breast augmentation, and it is the commonest cosmetic surgery procedure in women in the world.
Collagen, or any other injectable material is not useful for breast augmentation, and is not recommended. Collagen has many adverse effects, and has a tendency to migrate, and that can cause assymetry, which is very difficult to correct. The only injectable material, which can be used, is your own fat, but that also in small amounts, and not without problems. The shape and contour with breast implants is very pleasing, and as it has no side effects, is very commonly used all over the world with excellent results.