Hyaluronic acid fillers can be dissolved with hyaluronidase. Collagen biostimulators cannot — which is one reason the two are discussed as genuinely different treatments rather than interchangeable ones.
Overview
Only where volume has genuinely gone
Where volume has genuinely been lost, replacing it works. Where it has not, filler is the wrong tool and usually makes things worse.
Hyaluronic acid fillers restore volume immediately and predictably, and they are reversible — dissolvable with hyaluronidase if the result is not what either of us wanted. Those two properties make them the safest injectable in aesthetic medicine when they are used for the right indication.
The right indication is loss of structure: fat compartments that have deflated, bone that has receded, a fold that exists because the tissue above it has nothing to sit on. Used there, a small, well-placed volume changes a face quietly.
Used to chase a line that is actually a skin quality problem, or to add projection a face never had, filler produces the look that has made the word slightly embarrassing. We would rather under-treat and see you again than be part of that.
At a glance
- Treatment time30–45 minutes
- AnaestheticTopical; lidocaine is contained in most products
- DowntimeSwelling for 1–3 days; bruising possible for a week
- SessionsOne, with review at 2–4 weeks
- ResultsImmediate; typically last 9–18 months by product and site
- Combines withWrinkle-relaxing injections, bio-stimulation, subcision
How it works
Replace structure, not surface
Hyaluronic acid is a naturally occurring molecule that binds water. In filler form it is crosslinked to control how firm it is and how long it persists, and different products are engineered for different planes: a firm gel deep on bone behaves entirely differently to a soft one placed in the dermis.
It is also not quite as inert as it is usually described. Biopsy studies in human skin show that a crosslinked gel physically stretches the collagen-producing cells of the dermis, which switches them back into an active state; new collagen appears around the gel from about four weeks and continues to accumulate for at least a year. The mechanism is mechanical rather than chemical — fibroblasts do not bind hyaluronic acid, they respond to being pulled. What has never been studied is the state of skin once a filler has completely degraded, so we are careful in both directions: it is not true that the skin is left exactly as it was, and it is not true that filler permanently alters the face.
Placement is planned in layers. Support goes deep, refinement goes superficial, and the total volume is kept as small as the result allows.
In scar work, a soft hyaluronic acid can be used after subcision to support a released scar floor — but not in the same session as tumescent anaesthesia, which would simply carry it away.
Indications
Suited to
- Mid-face volume loss and flattening
- Deep nasolabial folds and marionette lines
- Temple hollowing
- Jawline and chin definition where structure is genuinely lacking
- Lip hydration and shape, treated conservatively
- Tear trough hollowing in selected patients
- Supporting a scar floor after subcision
- Skin quality complaints — crepiness, texture, dullness — which volume does not fix
- A face that has not lost volume but wants more of it
- Previous permanent filler at the same site
- Active autoimmune or granulomatous disease
- Imminent dental work or vaccination, which are associated with delayed reactions and are worth timing around
- Body dysmorphic features, where no amount of product is the right answer
In the clinic
Step by step
Assessment
The face is assessed in three dimensions, at rest and in movement, and the pattern of loss identified. Sometimes the conclusion is that filler is not what you need.
Planning and consent
Product, plane and volume are agreed, along with the honest risks — including the rare vascular ones.
Injection
Needle or cannula depending on the site. Most products contain lidocaine, and treatment is comfortable.
Immediately after
Swelling for one to three days; bruising is possible for a week. Avoid heat, alcohol and heavy exercise for 24 hours.
Review at two to four weeks
Assessment once swelling has fully settled, and a small refinement if needed.
Recovery
Downtime, honestly
The same day
Swelling, and in the lips a great deal of it. What you see on the day is not the result and should not be judged as one.
Days one to three
Peak swelling and any bruising. Firm areas are normal and usually settle without intervention.
Days seven to fourteen
The gel has integrated and the swelling has gone. This is the first honest look at the outcome, and the point at which anything is adjusted.
Months six to eighteen
The visible effect fades at a rate that depends on the product, the plane and how mobile the area is. Mobile areas such as the chin clear faster than the deep midface.
Worth knowing
Imaging studies have found gel still present long after the visible effect has gone — more than two years in the lateral face in one documented case. That is an argument for treating less often rather than more, and for assuming nothing about what is already there.
Risks
What can go wrong
Expected
Swelling and bruising for two to seven days, longer in the lips. Temporary firmness.
Uncommon
Visible lumps or asymmetry, almost always correctable. Delayed inflammatory nodules appearing more than a month afterwards, at an average rate across products of a little over one per cent — often triggered by an intercurrent viral illness, a vaccination or dental work. The cause remains genuinely disputed.
Rare but serious
Vascular occlusion. If the gel enters an artery it can block the blood supply to skin, or travel backwards into the vessels supplying the eye. Published cases of visual loss now number in the hundreds; the nose, forehead and glabella account for the great majority, and hyaluronic acid is the product involved in about four in five.
One thing is worth saying plainly, because it is usually said the other way round. Filler is reversible, and hyaluronidase is a real safety advantage against lumps and against a result you dislike. It is not a reliable rescue for a vascular event: in the largest review of visual loss, no treatment — hyaluronidase included — was significantly associated with recovery of sight. The safety story is prevention: anatomy, plane, aspiration, slow low-pressure injection, cannulae where they are appropriate, and declining the highest-risk sites when the indication is marginal.
Evidence
What the evidence shows
Strong, including on the risksInjectable filler is the only intervention for acne scarring that the Cochrane review graded at moderate certainty — most of the rest of that field is rated low or very low. The caveat matters, and we would rather state it: that finding rests on a single trial of a polymethylmethacrylate-collagen product, not of hyaluronic acid.
The dermal-remodelling evidence is good: randomised and placebo-controlled in human skin, with the mechanism specified down to the signalling pathway. Its main caveat is that the biopsy studies were done on forearm and buttock skin in people over seventy, which is a reasonable but real extrapolation to a forty-five-year-old’s midface.
The risk evidence is better than for almost anything else here, because serious events get published. That is why the numbers on this page are specific rather than reassuring.
If you are travelling
Flying the same day is fine. Flying to an event the next day is not — allow two weeks between treatment and anything you want to look your best for.
A top-up, where one is needed, is at two to four weeks. For international patients we would rather treat conservatively and review on photographs than treat generously because you are only here once.
If anything concerns you after you have travelled home — particularly pain out of proportion, blanching or mottling of the skin — contact us immediately and seek care locally the same day. That is the one complication where hours matter.
Questions
Good to know
If your question is not here, ask it in the enquiry form — Dr. Henningsen answers these personally.
Ask a question- Is it reversible?
- How long do they last?
Typically nine to eighteen months depending on the product, the site and how much you move that part of your face.
- What are the serious risks?
Vascular occlusion — filler entering or compressing a blood vessel — is the one that matters. It is rare, and it is why filler should be placed by a doctor who knows the anatomy and keeps hyaluronidase in the room.
- Can filler treat acne scars?
Indirectly and temporarily. A hyaluronic acid can lift a depressed scar, but it does not address the tethering that created it. Subcision plus a biostimulator is the durable version of that idea.
Consultation
Ready to talk about your skin?
Consultations with Dr. Henningsen are arranged individually. Tell us what you would like to change and we will come back to you with the options, the honest downtime and the realistic result.