The Science of Fillers
What exactly are hyaluronic acid fillers?
While there are many types of fillers on the market, hyaluronic acid (HA) fillers tend to be the most commonly used today. This is likely due to their safety of use and reversibility. HA is actually already naturally found in our bodies and provides hydration and rigidity or turgor to our skin cells and protects them from damage. This is one of the main reasons why HA has a good safety profile when injected into the skin.
The various fillers on the market differ in their properties and, as a result, differ in the way they respond once injected. Specifically, they respond differently to the surrounding muscles, skin, and gravity as they apply forces to the fillers such as shearing, compression, and stretch. These properties determine which fillers would be best suited for different areas of the face. Here is the science. These properties include G’ which is the filler’s ability to rebound to its original shape after injection or resist compression. A higher G’ generally correlates with a firmer gel and one that would be ideal for deeper injections to generate that “lifting” power such as in the cheeks. Voluma and Restylane Lyft are great examples of this. G” denotes it’s resistance to dynamic forces or it’s viscosity, sometimes also referred to as n*. Higher G” are thicker, while lower G” are thinner liquids. Gel cohesion refers the ability of the gel particles to “stick together” and remain intact as a gel after injection. The concentration of HA within the filler and how these particles are cross-linked together play a role it’s cohesivity and durability. Finally, the size of the particles themselves plays a role in the lifting power of the gel and its affinity to water or hydrophilicity determines the amount of swelling you might see following injection.
Too much science for you? While that may be true, these are all important factors that your doctor or injector must understand when using these products. This knowledge will help them use the best product for each concern that you might have. For instance, you would not use the same filler under the eye as you would in the cheeks. You would also not use the same filler in a superficial thin wrinkle as you would in the nasolabial folds for instance.
So many of our patients come in requesting one filler by name. Perhaps this is what their friend had injected or a commercial they saw. Regardless, it’s our job to ensure that we discuss each of your primary concerns and recommend the safest filler that will allow you to achieve your goals.