Hyaluronic Acid Fillers (Restylane / Juvederm)
The cosmetic physicians have been looking for an injectable substance to fill up or augment the soft tissue in the skin. The ideal substance should be non-toxic, does not cause allergic or inflammatory reactions, is stable after injection, will not lose easily but can be reabsorbed.
Different injectable cosmetic fillers have been used to replace the lost matrix volume by injecting into the dermis. There are many types, the earliest kind was probably collagen derived from animals. Now the most popular dermal filler is Hyaluronic Acid. There are many different brands including Restylane, Juvederm, and Hylaform.
Hyaluronic acid is a natural complex sugar formed by Glucosamine and Glucuronic acid. It is found in all living cells, and its basic structure is the same in different species. It retains water like a sponge, absorbing more than 1000 times its weight, and forms a highly concentrated gel material.
It is a major component of the dermis connective tissue matrix, along with collagen and elastin. Its property helps to attract hydration and maintain volume in the skin. If the collagen and elastin are the steels rods, then the hyaluronic acid and water in the dermal matrix is the cement concrete.
As we age, apart from the loss of collagen and elastin in the dermis, the support dermal matrix also loses its volume. As a result, the natural volume of youthful skin begins to diminish, and wrinkles and folds form.
It is very simple. After being injected into the dermis, it absorbs and retains water, and the expansion will enhance the volume. It is slowly broken down into carbon dioxide and water in the liver. Special preparations are needed to increase its stability and slow this down, so that the cosmetic effect will be longer lasting.
Common uses include:
There are different concentrations as well as particle sizes for applications in different areas. If injection is made in a deeper level of the dermis, then a larger particle size is chosen to avoid too early re-absorption.
Here are some examples of the treatments:
How Is It Done?
Because hyaluronic acid dermal fillers are non-animal-based, they can be administered without pre-testing. (Unlike bovine collagen, which is derived from animals, i.e. cow, and requires an allergy test.)
The volume of gel injected is actually very small, ranging from 0.4cc to 1.0cc. This is done using an ultra-fine needle. There is some pain but usually well tolerable and the doctor may apply a local anaesthetic cream on the area for an hour prior to the injection.
The result is immediately noticeable. Often the wrinkle or fold will be diminished by 50 - 80%, or more, depending on the severity and the amount of filler used. The result will usually last for 6 - 9 months. As the filler is slowly re-absorbed, the enhanced volume will shrink gradually. After that, it needs to be repeated again.
Hyaluronic acid dermal fillers are proven to deliver a longer-lasting effect than traditional bovine collagen.
After injection, the area may appear a little red and swollen, but this is usually very transient. Occasional it may cause a bruise, which will last for a few days. Those taking aspirin have a higher chance of a bruise.
There are reports of an immediate and a delayed type hypersensitivity reactions. This may be related to uses of products from lesser-known companies in some countries, and may be due to impurities during the preparation process. It is better stick to the more researched and approved products.