Dermal fillers, explained for patients

What a dermal filler is

A dermal filler is a gel implanted under the skin with a needle or a cannula to add volume, restore a contour or soften a fold. It is not a drug and it is not a muscle relaxant. In the United States, the FDA regulates dermal fillers as medical device implants, and its approval of each one is based on controlled clinical study of the product in the face or hand ^{(source, verified Nov 2026)}. That approval is specific: each product is approved for certain areas, at certain depths, in adults of a certain age. approved fillers are intended for adults aged 22 and older ^{(source, verified Nov 2026)}.

What the approvals cover is narrower than what patients often assume. absorbable fillers are approved for moderate to severe facial wrinkles and skin folds such as nasolabial folds and perioral lines, for adding volume to the lips, cheeks, chin and the back of the hand, for restoring facial fat loss in people with HIV, and for correcting contour deficiencies such as acne scars ^{(source, verified Nov 2026)}. On the other side of the line, no filler is approved for injection into the glabella (between the brows), the nose, the area around the eyes, the forehead or the neck, and none is approved for body contouring ^{(source, verified Nov 2026)}. Treatment in those areas is off-label. That is legal and common when a prescriber judges it appropriate, but it should be named as off-label in the consultation, and the risks of those areas are different, as the filler safety guide explains.

This guide is the general reference. The dermal fillers treatment page describes how Tanya plans a visit; the filler safety guide owns complications in depth.

The main materials

Fillers are grouped by what they are made of, because the material decides how the gel behaves, how long it lasts and whether it can be reversed.

Hyaluronic acid. A sugar the body already makes, found in skin and cartilage. Filler-grade hyaluronic acid is usually produced by bacterial fermentation, then cross-linked so the body breaks it down more slowly than its own. This is the largest group, and the one that can be dissolved with hyaluronidase. Juvéderm, Restylane and RHA are brand families of hyaluronic acid filler. On this site, “filler” means hyaluronic acid filler unless another material is named.

Calcium hydroxylapatite. A mineral found in teeth and bone, suspended in a gel. It adds support at once and, as the gel carrier is absorbed, the particles stimulate the body to lay down collagen around them. It shows on X-rays, which is worth telling a dentist or radiologist. Radiesse is the brand. It cannot be dissolved with hyaluronidase.

Poly-L-lactic acid. A biodegradable synthetic material, long used in dissolvable sutures, injected as a suspension. It adds little volume on the day; its effect comes from collagen the body builds over a series of sessions. Sculptra is the brand. It cannot be dissolved with hyaluronidase. The site groups calcium hydroxylapatite and poly-L-lactic acid as biostimulators.

Non-absorbable fillers. The FDA has approved one material that the body does not absorb, polymethylmethacrylate beads suspended in collagen. non-absorbable fillers are approved only for nasolabial folds and cheek acne scars ^{(source, verified Nov 2026)}. A result that cannot be reversed is a different kind of decision, and this site does not cover those products further.

How hyaluronic acid fillers differ from one another

Two syringes of hyaluronic acid filler can behave very differently. A product’s labeling and the rheology literature describe the differences in three main terms. The explanations below follow an overview published in Facial Plastic Surgery.

Cross-linking. Hyaluronic acid on its own is a liquid that the body clears in days. Cross-linking bonds the chains into a gel. More cross-linking makes the gel firmer and more resistant to the enzymes that break it down, so it lasts longer; less cross-linking makes a softer gel that integrates into fine tissue more easily.

Concentration. The amount of hyaluronic acid per millilitre of gel. Within one manufacturer’s technology, a higher concentration generally means a firmer gel that draws in more water and lasts longer. Concentration alone does not predict firmness across different technologies, which is why two products with the same concentration can feel quite different.

G prime. The term injectors use most. G prime (written G′) is a laboratory measure of how strongly a gel springs back when it is pushed on, in plain words its firmness. A high G prime gel resists deformation and holds a shape, which suits deep placement for structure in the cheek, chin or jawline. A low G prime gel yields and spreads, which suits lips and fine lines where a firm gel would be felt or seen. The overview is careful to note that G prime is a proxy for lift, not a direct measure of it, and that values from different laboratories are hard to compare. A related property, cohesivity, describes how well the gel holds together under pressure; it depends on both concentration and cross-linking, and there is no standard way to measure it.

As an example of what labeling says: Juvéderm Voluma XC is a cross-linked hyaluronic acid gel at a concentration of 20 mg/mL with 0.3 percent lidocaine, approved for deep injection for cheek augmentation to correct age-related volume loss in the midface in adults over 21 ^{(source, verified Nov 2026)}. Other members of the same family are formulated softer for lips and fine lines. Which product suits which area is a planning decision made at the consultation, not a feature a patient needs to choose from a list.

What fillers can and cannot do

Fillers restore or add volume, define a contour and soften a crease or fold. They can fill a hollow cheek, add structure to a chin or jawline, define or add fullness to lips, and soften the fold from the nose to the mouth corner.

What they cannot do matters as much. A filler does not lift tissue that has descended; it can restore support beneath it, which may change how the surface looks, but it is not a facelift. The American Society of Plastic Surgeons’ patient guidance says plainly that for some people surgery is the better approach and that minimally invasive treatments cannot achieve the same results. A filler does not change skin quality: texture, pores, pigment and fine crepe are skin problems, not volume problems. A filler does not relax a muscle, so a line made by expression is a neuromodulator question (neuromodulators, explained). And a filler is temporary: the result needs maintenance, and the FDA notes that using fillers together with neuromodulators such as Botox, and long-term repeated use, have not been studied in controlled trials ^{(source, verified Nov 2026)}.

What a treatment visit involves

The outline below is general. The dermal fillers treatment page describes how Tanya runs a visit.

Consultation. What bothers you, what you want it to look like, your medical history, allergies, medicines and supplements, past treatments, and whether the thing you came in about is the thing that would make the difference. Volume loss in one area changes how a neighboring area looks, so the first recommendation is sometimes not the area you asked about.

Good Faith Exam. Tanya practices under a delegating prescriber, and new patients have a Good Faith Exam before treatment. A prescriber reviews your history and examines you, in person or by live video, before an order for treatment is written. How that works, and why.

The plan. Which areas, which product, how much, at what depth, in what order, and over how many visits. A good plan says what will not be treated and why.

Consent and photographs. Written consent covers the product, the areas, the expected effects and the risks, including off-label areas if any are planned. Standardized photographs are taken before treatment so that the result, and any problem, can be compared against a baseline.

The injection. The skin is cleaned and marked. Filler is placed with a needle or a cannula, in small amounts, with the injector watching the skin as she goes. Many products contain lidocaine; a topical anesthetic may also be used. The injection part of a visit is usually the shortest part.

Aftercare and follow-up. Written aftercare on what to expect, what to avoid, and what to call about. Swelling and bruising are expected (how long lip filler swelling lasts). A follow-up once swelling has settled is where the result is judged and any adjustment discussed.

How long results last

Duration depends on the material, the specific product, the area, how much was placed and how deep, and the person. The ranges by material are in the Numbers callout above. For a single product, the FDA’s own review of the approval study gives the clearest picture of what “up to two years” means in practice: in the pivotal cheek study, 86 percent of treated subjects were still responders at 6 months, 85 percent at 12 months and 67 percent at 24 months, after a mean injection volume of 6.8 mL ^{(source, verified Nov 2026)}. Two things follow. A majority of people still had a measurable result at two years, and a third did not. And the volume used in that study was large by everyday standards; a smaller treatment is not expected to last as long.

Lips and other mobile areas are generally treated with softer gels and are expected to last toward the shorter end of the hyaluronic acid range. Deep, firm gels on bone last toward the longer end. Tanya will say at the consultation what is reasonable to expect for the plan proposed, with the labeling as the reference.

Risks, in brief

Every filler injection carries risk. The filler safety guide covers each of these in depth and explains how a careful injector lowers the risk; this section is the summary.

Expected. Swelling, bruising, tenderness, redness and firmness at the injection sites. In the cheek study behind one product’s approval, 98 percent of subjects reported a local treatment site response such as tenderness, swelling, firmness, lumps or bruising, mostly mild or moderate, with a duration of 2 to 4 weeks and a median time to complete resolution of 6 days ^{(source, verified Nov 2026)}. In lips, swelling was reported by 74.3 percent of participants in a pooled analysis of lip filler studies, and these events mostly resolved without treatment within a few weeks ^{(source, verified Nov 2026)}.

Uncommon. Lumps that can be felt, which are usually gel that has not settled or swelling around it. In the same cheek study, a lump or mass at the treatment site was recorded as an adverse event in 18.9 percent of subjects and firmness in 14.1 percent ^{(source, verified Nov 2026)}. True granulomas, the body walling off the material, are different and rare: true foreign-body granulomas are rare, with an estimated incidence between 0.01 and 1 percent ^{(source, verified Nov 2026)}. Also uncommon: the Tyndall effect, a bluish tint when hyaluronic acid filler sits too close to the surface; migration, gel moving from where it was placed, most often in mobile areas such as the lips; infection; and late swelling triggered by illness, vaccination or dental work. The American Society of Plastic Surgeons’ guidance adds asymmetry and under- or over-correction to the list, and notes that severe complications are uncommon.

Serious and rare. Filler injected into an artery, or pressing on one, cuts off the blood supply to the skin that artery feeds. This is a vascular occlusion. Unrecognized, it can cause tissue death and scarring; if the filler reaches the arteries that also supply the eye, it can cause vision loss. The FDA calls unintended injection into a blood vessel the most concerning risk of fillers. In a published survey, a survey of 370 dermatologists covering about 1.7 million syringes found about one vascular occlusion per 6,410 one-milliliter syringes injected with a needle and about one per 40,882 injected with a cannula ^{(source, verified Nov 2026)}. For sight, a review identified 60 published cases of vision loss after hyaluronic acid filler across 29 articles, most often after injections in the nose, the glabella and the forehead ^{(source, verified Nov 2026)}. Those sites are the ones no filler is approved for. What a vascular occlusion is, and the warning signs is written for anyone who has had filler. Any change in vision during or after a facial injection is an emergency.

Reversal with hyaluronidase

Hyaluronidase is an enzyme that breaks down hyaluronic acid. Injected into hyaluronic acid filler, it dissolves the gel over hours. It is used electively, to soften or remove a result, and urgently, to clear a blocked vessel. It does not act on calcium hydroxylapatite, poly-L-lactic acid or non-absorbable fillers, which is a reason to ask what is in the syringe before it goes in.

Two things to know. in the United States, using hyaluronidase to dissolve cross-linked hyaluronic acid filler is an off-label use, and patients should be told so as part of consent ^{(source, verified Nov 2026)}. And after elective dissolving, the guideline recommends waiting a minimum of two weeks after dissolving before new filler is placed in the same area ^{(source, verified Nov 2026)}. The filler safety guide has a dedicated article on what happens when filler is dissolved with hyaluronidase.

Who is not a candidate

Fillers are deferred or declined for some people, and this is what the Good Faith Exam screens for. the FDA advises against fillers for anyone with a bleeding disorder, severe allergies or a history of anaphylaxis, says treatment should be delayed while skin is inflamed or infected, and notes that safety has not been established in pregnancy, while breastfeeding, under age 22, or in people prone to keloid or hypertrophic scars ^{(source, verified Nov 2026)}. Product labeling adds its own contraindications; the Voluma labeling, for example, excludes people with a history of allergy to lidocaine or to the bacterial proteins the gel may contain in trace amounts.

Beyond the labels, an injector should be cautious with someone who has had a previous reaction to any filler, anyone with a non-absorbable or unknown product already in the area, anyone with an autoimmune condition that flares with inflammation, and anyone whose expectations a filler cannot meet. Recent dental work is a reason to postpone, because of the infection risk. “Not now” is a legitimate outcome of a consultation.

Questions to ask at a consultation

• Which product is proposed for each area, and what is it made of? Can it be dissolved?
• Is any part of the plan off-label, and what are the particular risks of that area?
• Who is the delegating prescriber, and how is the Good Faith Exam arranged for a new patient?
• How much is proposed, and could the plan be split across more than one visit?
• Is hyaluronidase in the room, and what is the plan if a vessel is blocked?
• What should I expect in the first two weeks, what should I avoid, and what should I call about the same day?
• Who do I call after hours?
• When is the follow-up, and what happens if I want less, or more?

Clear, unhurried answers are a good sign. An injector who cannot name the product or the prescriber is describing a shortcut.

Articles in this guide

Articles in this section, each on one area and the questions patients ask about it:

• What does cheek filler do, and how is it placed?
• What should I expect from a first lip filler appointment?
• What can jawline and chin filler change, and what can it not? (planned)

Until they are written, the filler safety guide and its articles on vascular occlusion and lip filler swelling cover the questions that come up most.