Collagen Injections and Other Cosmetic Fillers

Medically Reviewed by Stephanie S. Gardner, MD on September 18, 2023
6 min read

Collagen and other injectable wrinkle fillers give your skin a plumper, smoother appearance. While collagen is one of the best-known fillers, it requires prior allergy testing and is rarely used today. There are many other more commonly used substances doctors may suggest to plump up your skin, including fat from your own body, hyaluronic acid, calcium hydroxyl apatite, and poly-L-lactic acid.

To understand collagen, you should first understand your skin.

Skin consists of three layers: the epidermis, dermis, and subcutaneous tissue (hypodermis). The uppermost 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 springs back, no matter what our facial expressions are. And it stands up to 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 adds up and facial lines begin to appear.

Collagen injections replenish the skin's natural collagen.  By supplementing your skin's collagen, injections help smooth facial lines and some types of scars. The natural beauty of your skin is increased as the contour of the support structure is restored. Collagen can come from cows (bovine), pigs (porcine), or human cells.

Collagen injections include the following brands: Bellafill, CosmoDerm, CosmoPlast, Zyderm, and Zyplast.

Collagen may be the most widely known filler, but there are many others that work differently from collagen injections. Among them are:

  • Botulinum toxin (Botox Cosmetic, Dysport, Jeuveau, Xeomin) is not an actual wrinkle filler. Instead, botulinum toxin is injected into facial muscles to immobilize the underlying cause of lines and wrinkles. Botulinum toxin may improve eyebrow furrows, crow's feet, and forehead creases.
  • Calcium hydroxylapatite (Radiesse) is a semipermanent wrinkle filler that's suspended in a water-based gel. It’s used to increase soft tissue. It improves the surface texture of your skin and stimulates your own collagen to enable the product to last longer.
  • Fat from your own thighs or abdomen can also be injected. There's no risk of an allergic reaction since it’s from your own body. Most people achieve semi-permanent results. Several injections may be required to get the most benefit.
  • Hyaluronic acid  (Belotero, Elevess, Juvederm, Prevelle Silk, Restylane, Restylane Lyft with Lidocaine, Revance) is a substance normally made by the body that gives your skin its volume and fullness. Hyaluronic acid injections fill the space between collagen and elastin fibers within the skin. That replenishes the natural volume lost with aging. There is always a risk of skin infection with injections, and you will need repeated treatments to maintain the result. Hyaluronic acid also attracts and binds water, which helps maintain fullness where it's injected. Some hyaluronic acid materials are thicker and can add significant volume and structure. Others are smoother and thinner and have the ability to flow more consistently.
  • Poly-L-lactic acid (Sculptra) is an injectable filler used to replace lost facial fat. This synthetic polymer has been used for many years in dissolvable stitches and bone screws. This product stimulates the body’s own collagen for better skin texture and a longer-lasting result.
  • Polymethylmethacrylate beads (PMMA microspheres - Bellafill) are tiny round, smooth plastic particles. Thousands of synthetic PMMA microspheres are embedded in cow collagen, which is gradually absorbed by your body and replaced by your own collagen. Since the beads are not readily reabsorbed, and your own collagen is stimulated to form around them, this filler can last for years. Injections are placed under skin folds and in hollows to re-volumize and improve skin tone and texture.

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. You should have realistic expectations about what the results may be. 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’s why it’s a good idea to discuss cost. Keep in mind that health insurance doesn't pay for cosmetic procedures. So be sure you're clear on what you'll need to pay for and what your payment options are.

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.

The “softer” hyaluronic acid fillers like Restylane, Restylane-L, and Juvederm Ultra XC last 3 to 9 months or longer depending on the product and where it is placed. Other fillers last longer:

  • Radiesse and Restylane Lyft last up to 1 year or longer.
  • Sculptra, Juvederm Voluma, and Juvederm Vollure last up to 1 1/2 years or longer.
  • Bellafill is a semi-permanent filler that can last years.

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 and make wrinkles disappear. Creams primarily slow the rate of water loss from the skin and help keep the skin supple.