What Up G?
What’s Up with That G-prime Everyone’s Going On About?
As a client, you may have heard your injector casually tossing around the term “G-prime” when describing the choice of filler that they are recommending for you.
As a professional, you have probably been assailed by the term when being sold a particular brand of filler by a company representative. If your eyes are reflexively glazing over, please indulge me and keep reading — it’ll get more interesting.
Whatever your exposure to the term, you are probably a bit mystified by G’ (pronounced G-prime) and its relevance to Facial Rejuvenation. All commercially available fillers are viscous fluids that respect the laws of fluid dynamics.
While it may be gangsta’ to toss around the jargon, what exactly are the G-primes and what do they mean?
There are actually two terms incorporating the letter G when describing flow properties of fillers: G’ (G-Prime) and G” (G-Double-Prime). Both are used to describe the separate physical properties of viscosity and flow in fluid dynamics. In simple terms, they describe the energy stored in or energy required to affect change in laminar flow systems.
Since all fluids are compressible, G’ describes the amount of energy required to deform, or compress, a fluid. This is analogous to the amount of energy required to compress a spring. The stiffer the spring, the more energy it takes to compress it. In other words, the stiffer the spring — the higher it’s G’.
G” (G-double-prime) describes the amount of energy required to overcome the friction between layers in a fluid system. If it takes more energy to make the layers glide, then the fluid system is unlikely to flow absent the proper energy input. A higher G” means a less “flowy” fluid system. Jell-O will not flow unless heated and therefore has a higher G” than honey which flows easily at room temperature.
Now that we understand what the G is all about, we can properly match a filler, based on its physical properties, to the correct application in facial rejuvenation. For instance, if we want to create more projection and lift tissues, we would select a stiffer (high G’) and less flowing (high G”) filler such as Restylane LYFT or Merz Radiesse. If our goal is to correct dynamic wrinkles, we would select a softer (low G’) and higher flow (low G”) filler such as Prollenium Versa or Merz Belotero.
Your injector should have a thorough understanding of the properties of fillers and accordingly be able to recommend the ideal filler to achieve the desired aesthetic outcome in facial rejuvenation. Not all fillers are created equal just as all injectors are not.
Dr. Reddy is Board Certified in Plastic Surgery and has safely performed thousands of injections for facial rejuvenation. He was fortunate to study under the tutelage of the world renowned Dr. Arthur Swift while training in Plastic Surgery at McGill University, Montreal. If you are interested in non-invasive facial rejuvenation, schedule an appointment at RAI.
P. Pravin Reddy, MD is a Board Certified Plastic & Reconstructive Surgeon and a member of the American Society of Plastic Surgeons.