Fat lasts longer than gel and Botox injections. The important thing about fat injection is that fat is taken from the person's own body and injected into different areas of the body.Although this procedure requires a longer process than gel and Botox, it produces better results. Fat injections are always referred to as permanent fillers and have many fans due to the naturalness of the substances.The shelf life of fat after injection depends on various factors such as how the patient is cared for, how the doctor is injected, and the type of skin of the person, and all these factors make post-injection care more difficult for the patient.