Injectable Hyaluronic Acid Filler

Hyaluronic acid is a preferred ingredient for dermal fillers because it is naturally occurring in the body and therefore poses fewer risks of negative reactions. However, the half-life of hyaluronic acid is notoriously short and a normal hyaluronic acid filler degrades quickly.4 To create longer-lasting HA fillers, pharmaceutical companies created more durable formulations by chemically cross-linking the HA filler strands. These new formulations of hyaluronic acid filler can last from six months to two years based on the formula, the amount injected, and location.⁵

There are two kinds of possible breakdown of HA filler that affect its durability; metabolic and mechanical. Metabolic breakdown refers to how quickly a patient’s body metabolizes or “breaks down” the hyaluronic acid filler. Mechanical breakdown of HA fillers is related to movement of the area and will differ depending on the individual’s unique movements (such as facial expressions) and habits (for example, massaging the skin too vigorously will break down injectable hyaluronic acid more quickly). Some areas of the face such as the smile lines and around the mouth, break down hyaluronic acid filler faster due to repetitive movement, which is why hyaluronic acid lip filler may need to be touched up after 6 months.⁶ Other areas, such as the under eye where there is little mechanical pressure due to the soft and thin nature of the skin, injectable hyaluronic acid may last up to several years. As with any cosmetic procedure, the results and longevity will vary from patient to patient.

Injectable hyaluronic acid has been in use in Europe since 1996, and hyaluronic acid filler procedures have grown rapidly in popularity since the first FDA-approved HA filler, Restylane®, came on the US market in 2003.⁷ Improvements in hyaluronic acid filler formulations have steadily decreased the occurrence of negative reactions and increased the possible applications for injectable hyaluronic acid.

Lowered taboos around procedures such as hyaluronic acid filler and increased exposure on social media of hyaluronic acid lip injections and other HA fillers contributes partly to a more casual approach to injectable hyaluronic acid. Unfortunately, a black market of bootlegged hyaluronic acid filler on the internet and non-credentialed injectors are ready to take advantage of these consumers and the results have not been positive and often dangerous. Any substance injected into the body represents a medical procedure and should be treated with that level of caution and due diligence. When considering an injectable hyaluronic acid procedure consult only with a board-certified dermatologist or plastic surgeon using reputable and tested hyaluronic acid filler.

The correct age to start hyaluronic acid filler, if at all, is a personal choice after discussion with a trusted professional. While all skin will begin to lose bone mass and collagen around the mid-twenties⁸, the speed and expression of visible aging of the skin is determined by personal genetics and lifestyle and will be different for everyone. In general, most patients interested in HA fillers begin hyaluronic acid filler injections between the ages of 40 and 54. However, HA fillers used in procedures such as lip augmentation are becoming increasingly popular with younger patients. Some medical professionals even recommend the use of hyaluronic acid fillers as a preventative, anti-aging procedure, while others prefer to begin after the first signs of aging. It’s important to note, however, that while hyaluronic acid fillers may improve the appearance of the skin, they do not halt the aging process.⁹ Consulting with an experienced clinician with thorough knowledge of facial anatomy will help determine if hyaluronic acid filler is the appropriate choice.

One of the great advantages of hyaluronic acid filler over other dermal fillers is the non-permanent nature of HA fillers. Permanent and semi-permanent fillers have more possible long-term side effects such as stretching out the skin causing pockets of sagging skin. But, a judicious amount of hyaluronic acid filler that is properly placed does not pose a risk of creating areas of sagging or stretched skin. A more common outcome is for injectable hyaluronic acid to correct sagging skin due to aging by replacing lost volume. As the body metabolizes the hyaluronic acid filler, the skin will simply return to its previous state, which may appear more loose to the patient that has become accustomed to fuller, plumper skin from the HA fillers.

Although rare, it is possible for hyaluronic acid filler to migrate or move. This generally happens within the first few days after receiving the injectable hyaluronic acid when, for whatever reason, the HA filler moves before it has bonded with the tissue at the site of injection. To prevent HA filler migration, the general recommendation is to avoid any firm manipulation of an area treated with hyaluronic acid filler for three days after placement of the HA filler.¹⁰ Many practitioners offering services such as microcurrent or massage-based facial treatments will recommend waiting two weeks after a hyaluronic acid filler to avoid any possible negative effects on injectable hyaluronic acid.

In other cases, a provider may massage the HA filler or instruct the patient to do so for distribution of the material, a common occurrence with hyaluronic acid lip injections.¹¹ It’s important to follow the advice of the injector thoroughly as each case is unique. Lumps that appear after receiving injectable hyaluronic acid may be due to swelling or possibly a small hematoma at the site of injection which will resolve within a few weeks. It’s best to alert your provider to any changes or uneven textures in the treated area. Should an issue arise with the hyaluronic acid filler it can usually be corrected easily with the use of an enzyme, hyaluronidase, which can dissolve the hyaluronic acid filler completely in 48 hours.

Depending upon the circumstances, an administering practitioner may recommend back-sleeping with the head slightly elevated for a period after receiving hyaluronic acid filler. Post-procedure instruction may differ depending upon the location, the amount of HA filler used, and the health of the skin. ¹²As always, it’s important to follow the recommendations of the professional administering the treatment.

Properly placed hyaluronic acid filler poses small risk for negative side effects. But even in the best conditions, some patients may have an allergic response to injectable hyaluronic acid. In these cases, there are various treatment options depending upon the reaction. These interventions may include the use of steroids or an enzyme that dissolves the HA filler.^13,14
Although rare, possible side effects include:
Red, swollen, bruised skin
Itchy skin
Lumpy skin
Infection at the site of injection
Pain
Bleeding
Prolonged firmness
An abscess or nodule
Localized tissue death (necrosis)
Haemorrhage of the eyes
Double vision or loss of vision

Any of these symptoms should be reported to the provider immediately. Mild side effects are most common after hyaluronic acid lip filler, but are generally not serious.^15,16

Injectable hyaluronic acid is one type of temporary dermal filler used to correct imperfections and restore fullness. Other types of dermal filler that are also absorbed by the body over time, include the mineral calcium hydroxylapatite and the biodegradable, synthetic material poly-L-lactic. 17 Hyaluronic acid filler consists of hyaluronic acid (HA), a sugar molecule produced naturally in the body that attracts water and expands. This is the mechanism by which the injectable hyaluronic acid fills a deep space or line in the skin. It is a clear, gel-like substance and, depending on how the hyaluronic acid filler is engineered, it can be firm or elastic, depending on the desired application. The first HA product FDA approved for use in the face was Restalyne™ in 2003. ¹⁸

Animal-derived hyaluronic acid filler was the standard for some time, but it is expensive to process and presents risks of an immune response to accessory proteins bound to the HA filler. Innovations in production led to the manufacture of hyaluronic acid filler via large-scale bacterial fermentation with genetically modified strains. Most injectable hyaluronic acid in use today are from similar non-animal sources. The costs associated with producing bacteria-derived hyaluronic acid filler are lower and the process presents greater flexibility for creating products with higher molecular weight and complex cross-linking. These properties allow for hyaluronic acid fillers that are capable of providing more structural support and are slower to degrade. This variance is responsible for the diverse hyaluronic acid fillers on the market today, expanding the possibilities of injectable hyaluronic filler for cosmetic purposes. ¹⁹

Hyaluronic acid filler procedures are not available for a patient with active acne lesions or any infection (including herpes) in the treatment area. Patients with autoimmune disorders (or undergoing immunosuppressive therapy), blood-clotting problems, uncontrolled/untreated diabetes, or an allergy to any components of injectable hyaluronic acid are not candidates for HA fillers.

Pregnancy and breast-feeding patients should consult with their clinician when deciding whether or not to proceed with hyaluronic acid filler. Although there are no studies on the effects of injectable hyaluronic acid whilst pregnant or breast-feeding, many professionals advise against it out of an abundance of caution. However, some patients may choose to pursue treatment with injectable hyaluronic acid while pregnant and/or breastfeeding.

An emerging precaution highlights the connection between dental work and the risk of infection in an area treated with dermal fillers. Although more studies are needed, it is generally recommended to have any dental work completed before undergoing a dermal filler procedure.²⁰

Hyaluronic acid filler is administered by injection with a needle, so isn’t a completely pain-free procedure. However, most HA fillers are formulated with lidocaine, a numbing agent, that is activated immediately to reduce any patient discomfort. Some practitioners also administer an anesthetic gel before administering the injectable hyaluronic acid to maximize patient comfort.

One of the benefits of injectable hyaluronic acid is an immediate result, with improvements seen over the next few days as the hyaluronic acid filler settles in the tissues and begins being absorbed by the body. The final results of HA fillers is achieved after about one week and should last from 6 months to a year or more, depending on the formulation and placement of the hyaluronic acid filler. In general, a hyaluronic acid filler that has been engineered to be firmer will last longer than hyaluronic fillers designed for flexibility.

Most patients won’t experience any pain after having dermal fillers. But some people may find they have a little bit of soreness and/or mild bruising at the site of injection. If pain, bruising or swelling does occur, it may be alleviated with the use of an ice pack. As with any cosmetic procedure, it’s important to consult with the practitioner and report any uncomfortable or unusual side effects after treatment.