Hyaluronic Acid Dermal Fillers: Facts, Benefits, Risks, and What You Should Know
As we age, areas of hollow develop in our faces due to muscle and fat atrophy as well as gravity-driven downward slippage. Replenishing volume throughout specific areas of the face can restore some of our youthful vitality.
Most things injected into the face for volume restoration can be removed only with surgery to cut them out or with time, waiting years for the material to degrade.
The hyaluronic acids (HA) are the exception. They can be dissolved in minutes, breaking down into rapidly absorbed, non-toxic carbon dioxide and water.
The erasability of the HA was first revealed by our practice and has been arguably one of the main factors catapulting these fillers to the top of the cosmetic market.
Most commonly, the reason to dissolve HA is that the result was not exactly what was desired. However, the true value is the ability to resolve complications that may require intervention within minutes to avoid permanent problems.
What’s Actually Being Injected
Hyaluronic acid is a glycosaminoglycan, chemically speaking, a long “sugar” chain that grabs water and holds onto it, giving it the ability to produce volume expansion.
Your body already makes HA. It’s in your skin, your cartilage, the fluid in your joints, and the vitreous jelly in the back of your eye, which is why no allergy testing is needed. Your natural HA is constantly being cycled, created and broken down, lasting only days. If injectable dermal fillers behaved that way, nobody would bother.
To make commercial HA last longer, the sugars chains are “crosslinked,” chemically bonded into a stable gel that resists being broken down. They still break down into CO2 and water, but much more slowly, typically lasting a year or longer.
“I Had Filler” Says Almost Nothing
There are several filler products that are not HA, and these behave very differently, have their own durations of effect and unique sets of potential complications.
Knowing that you had treatment with HA, but not knowing which one is also somewhat problematic, since there are currently over two dozen injectable HAs available in the U.S., including the Restylane, Juvéderm, and RHA families, and equally as many more available overseas. Different HA products have different characteristics, which allows them to perform differently in different parts of the face and different parts of the body.
What Makes One HA Different from Another
The science used to characterize the behavior and properties of the different HA gels is called rheology, and the analysis can be a little daunting. Here are some of the more commonly used descriptive terms.
| Term | What it describes | What it means in the face |
|---|---|---|
| Crosslinking density | How tightly the HA chains are bonded together | Drives how long an HA lasts |
| G prime | How stiff the gel is and how well it holds shape under pressure | High G prime sits deep over bone, holds structure, and defines firm ridges like a jaw line or nasal ridge. Low G prime is more malleable and is typically used more superficially in fine facial lines. |
| Cohesivity | How well the gel stays together as one piece rather than dispersing | Affects how the product behaves once placed |
| Hydrophilicity | How well a gel pulls in water and holds on to it | Creates volumetric expansion |
Although there are clear differences among the fillers, several different fillers may perform well in a particular job in a particular part of the face, and the choice may come down to where else can that filler be used in the face to save on the cost of buying several different products.
“Which filler” should be a clinical question rather than an arbitrary brand preference.
What the HAs Do Well
Volume. That’s the honest, short answer. Volume loss or life-long deficiency in these areas are all frequent targets:
- Midface and cheek bones
- Nasolabial folds and lips
- Ear lobes and temples
- Brows and chin
- Under eye hollows
Reshaping and “straightening” the nose brings HA use to a different level. HAs work the day they are injected. There’s no real downtime past bruising and swelling, and unlike the botulinum toxins, you can see the result before you leave.
Then there’s reversibility, which separates the HAs from every other filler class. Hyaluronidase degrades hyaluronic acid within minutes, allowing alteration to things you don’t like and most importantly, offering an “antidote” for any complication. Hyaluronidase selectively, permanently removes the injected HA, while allowing your natural HA to reform as it always does.
What HAs Don’t Do
- They don’t tighten skin.
- They don’t remove skin.
- They don’t truly lift tissue that has descended, although they can sort of create that impression. If you put your hand up beneath your shirt and push away from your body, you will see the bottom edge of your shirt rise, but it takes a lot of distance between your body and your shirt to make that happen.
- They do nothing for pigment. A dark area caused by skin pigmentation with melanin, or by vessels showing through thin skin, stays dark after a perfectly placed treatment.
- They’re temporary. Usually, the right HA used in the right place should last at least a year, and sometimes as long as a decade or longer. Aging is a progressive process, and a permanent solution slapped on a changing problem will eventually fail. The HA solutions can change as our faces do.
If your complaint is loose lower eyelid skin or fat pushing forward, adding volume underneath may be helpful, but it might not. An experienced injector should be able to make reasonable assessments and predictions.
Worth establishing which kind of dark circles you have beneath your eyes, before someone bills you for a treatment only designed to remove shadow.
The Risks
The risks are real and unfortunately often buried in a quickly initialed consent form without the serious conversation they deserve.
Vascular occlusion
Anything injected into the face that is thicker than water carries a risk of interrupting blood flow either through vessel compression or the introduction of material directly into a small artery creating a floating cork, or embolus. What follows may range from segmental temporarily dark, dusky skin to delayed skin/muscle tissue death to even rarely reported permanent blindness if the filler makes its way into the ophthalmic artery.
Certain zones come up again and again in the literature – the glabella between the eyebrows, the nasal dorsum, the nasolabial region, and the area around the eye, but injections anywhere in the face may have problems as the material injected in one place travels to another.
The warning signs are obvious and immediate. Pain out of proportion to what’s being done. Skin blanching white and then becoming mottled or dusky. Any change in vision at all.
None of that is a wait-and-see situation and should be apparent immediately; however, if symptoms develop after you’ve left an office, an urgent call to the injector is warranted. In some cases, minutes make all the difference.
Although bruising most often is benign, deep bruising might merit a phone call and an emailed photograph to the injector.
Any practice injecting HA filler should keep the antidote hyaluronidase on hand and have a protocol for using it, especially in the event of vision loss. It is completely reasonable for you to ask if they have fresh hyaluronidase immediately available and to ask to see their written crisis protocol. In the chaos of an extremely rare and terrifying event, nobody wants to rely on vague memory.
The good news is that the HA fillers are the only ones that do have an immediate solution, if one is needed. The other fillers don’t.
Lumps that show up late
Firm nodules can appear weeks or months afterward, and they’re a different animal from the lump you feel on day two. Early lumps are usually due to a deep bruise or thick placement that is only recognizable as the filler pulls in water. These are all typically correctable with deep massage or hyaluronidase. Delayed inflammatory nodules, however, may involve a bacterial biofilm or your immune system reacting, and sorting them out can mean antibiotics, steroids, and/or hyaluronidase dissolution.
The Tyndall effect
HAs sitting too shallow under thin skin scatters light and may appear bluish or grey. The lower lid is the classic spot, because the skin there is the thinnest anywhere on your body. Different HAs have different predilections for creating a Tyndall effect, and choosing another HA or using hyaluronidase can resolve the problem.
The ordinary stuff
Bruising, swelling, tenderness, redness, temporary asymmetry are all normal and most often resolve on their own. Swelling around the eye after tear trough treatment can run longer than elsewhere due to the thinness of the tissue where “everything shows,” the highly vascular nature of the tissue, and the particular pattern of lymphatic drainage.
What to Sort Out Before Anyone Injects You
- Know who’s holding the syringe. Who’s holding the syringe often matters much more than what’s in it. The area around the eye isn’t a place to be someone’s learning curve. You’re entitled to ask what training and experience they have, how often they treat this specific area, and what happens if a vessel gets occluded. An injector who finds these questions irritating or offensive has already answered one of them.
- Say what you’re taking. Anticoagulants, antiplatelet drugs (especially “baby” aspirin), and supplements including fish oil, vitamin E and ginkgo among others, all raise bruising risk. Don’t stop a prescribed medication on your own. That’s a conversation with whomever prescribed it.
- Mention old filler, all of it. Filler placed years ago may still be sitting there, and it may alter how additional new products behave.
- Know that some situations are a no. Active infection at the site, known hypersensitivity to a component. Allergy to Yellowjacket venom, because it contains hyaluronidase, which is the antidote in the event of a serious complication. In general, the HA fillers aren’t used in pregnancy or while breastfeeding, because the safety data doesn’t exist.
- Don’t judge it at 48 hours. Swelling misrepresents the result early, and people request corrections to swelling all the time. Wait at least two days or until the bruising is gone to determine the effect.
Talk to Someone Who Treats the Area Every Day
Filler around the eye isn’t the same conversation as filler anywhere else in the face. Thin skin showing everything, vascular anatomy that connects to places you’d rather it didn’t, and a higher complication profile merit seeking out someone with considerable experience.
Ask any injector the same five things before you begin:
- What’s their training?
- How often do they treat the area around the eye?
- How many years have they been doing so?
- Do they have hyaluronidase immediately available?
- What would they do in the event of an emergent crisis?
If you would like to have that conversation with us, call for a consultation.
Frequently Asked Questions
How long does hyaluronic acid filler last?
Commonly cited at roughly 6 to 18 months, but the right filler in the right place should last about a year, sometimes as long as a decade. Different people degrade HAs at different rates. Filler in the lips may not last as long, because mobile areas break filler down faster and typically thinner fillers are used in the lips to avoid irregular lumps.
Can HA be removed if I don’t like it?
Yes. Hyaluronidase dissolves it. Our practice is the one that discovered this solution. This is the real advantage HA holds over filler classes that can’t be reversed, and it’s worth factoring in if you’re nervous about a first treatment.
Will filler fix my under-eye bags?
Depends on the size of the “fat bag,” the projection of the cheek, the depth of the hollow beneath the eyes, and the character of the skin. An examination by an experienced injector will provide the best answer for each individual.
Is filler safe around the eyes?
It can be highly effective, but remains one of the higher risk zones in the face, because of the high vascularity around the eyes. This is an area where who injects you matters disproportionately.
What are the signs something has gone wrong?
Pain that seems out of proportion. Skin blanching, or going dusky and mottled. Any vision change. Those mean contacting your injector immediately rather than waiting, because the treatment window for a vascular event may be measured in minutes, not hours or days.
Does it hurt?
Less than people expect, generally. Most HA products include lidocaine, and topical numbing is standard. Bruising bothers patients more than the injection itself, particularly around the eye.
The Bottom Line
Hyaluronic acid fillers restore lost volume, work the day they’re injected, and, unlike every other filler class, can be dissolved in minutes if something isn’t right. They don’t tighten, remove, or truly lift skin, and around the eye the risks are real. The product matters, but who’s holding the syringe matters more.
Considering filler around the eyes? Talk with an oculoplastic surgeon who treats the area every day.
