context: Collagen injections give your skin a plumper, smoother appearance. Although collagen is the best known filler, there are many other substances doctors can use to plump up your skin, including fat from your own body and synthetic materials. Below you will find a detailed explanation of how collagen works, followed by a list of other injectable fillers your doctor may recommend. To understand collagen, you should first understand your skin. Skin consists of three layers: the epidermis, dermis, and subcutaneous tissue (hypodermis). The upper-most layer, known as the epidermis, controls the loss of water from cells and tissue. Without this protective barrier, the body would quickly dehydrate. Just below the epidermis lies the second layer, the dermis. The dermis, although it contains blood vessels, nerves, and hair follicles, is primarily made up of a protein called "collagen." This protein forms a network of fibers that provides a framework for the growth of cells and blood vessels. Because it is the primary component of the dermis, collagen acts as the support structure for the skin. The hypodermis is a layer of fat and connective tissue that contains larger blood vessels and nerves. It also hosts sweat glands, fat, and collagen cells. The hypodermis is responsible for conserving your body's heat and protecting your vital inner organs. In young skin, the collagen framework is intact and the skin remains moisturized and elastic. It's resilient to the many facial expressions we adopt, as well as everyday environmental exposure. But, over time, the support structure weakens and the skin loses its elasticity. The skin begins to lose its tone as the collagen support wears down. Every time you smile, frown, or squint, you put stress on the collagen in your skin. The effect of these facial expressions is cumulative and facial lines begin to appear. Collagen injections replenish the skin's natural collagen. The natural beauty of your skin is enhanced as the contour of the support structure is restored. Collagen should be injected into your skin only by a trained health care professional. Before getting a collagen injection, you will need a collagen skin test. A small amount of collagen is injected in the forearm and the area is monitored over the next month looking for any signs of an allergic reaction. If you don't have any indication of an allergy, your doctor can proceed with collagen treatments. You may receive a small injection of local anesthesia to numb the area being treated. There is a possibility of slight bruising, and you may experience puffiness, redness, and tenderness around the treated site. It's important to discuss with your doctor exactly what you can expect from each treatment. Together, you can prioritize which facial areas you wish to have treated and discuss how many treatments you may need and the estimated cost. It's important to know that one treatment probably will not remove every line on your face. Depending on the substance injected, you will need continued treatments to maintain the smoothing effect. That depends on which product you use. Just like natural collagen, collagen replacements begin to lose form and will eventually wear down. Treatment may require collagen injections two to four times a year to maintain the smoothing effects. You and your doctor will discuss your medical history and the areas you want treated with injectable fillers. Injections are not appropriate for certain lines and scars or when certain medical conditions are present. It is very important to discuss and understand what filler injections can do for you. If you and your doctor decide injections are appropriate, your doctor may start with a skin test in your forearm to determine if you are sensitive to the substance being used. You must watch the area very carefully over a four-week period. Most men and women tested show no reaction to the skin test. Collagen creams work only on the skin surface. A moisturizer with or without collagen cannot penetrate the skin and is not designed to be absorbed. No moisturizer can undo the cumulative effect of collagen loss. Creams primarily slow the rate of water loss from the skin and help keep the skin supple. These fillers work in different ways from collagen injections. Ask your doctor which is best for you. Radiesse Sculptra Juvederm, Juvederm Voluma, Juvederm Voluma XC, Juvederm Ultra, Juvederm Volbella XC, Juvederm Ultra Plus and Juvederm Ultra Plus XC Restylane, Restylane Lyft, Restylane Silk, Restylane Refyne, Restylane Defyne Belotero Balance Bellafill