"Filler" is one of the most searched words in cosmetic medicine — and one of the most misunderstood. Patients often arrive at the clinic asking for "filler" as if it were a single product. In reality, dermal fillers are a family of injectable materials with very different compositions, behaviours, lifespans and ideal uses. Choosing among them is a medical decision, not a menu order.
This article walks through the main categories used in evidence-based practice today, what each does well, and how a dermatologist decides which one belongs in which area of the face.
Hyaluronic acid (HA) fillers — the modern workhorse
Hyaluronic acid is a sugar molecule your skin already produces naturally; it holds water and gives young skin its plumpness. HA fillers (brands you may know include Restylane, Teosyal and Juvéderm) are smooth gels of stabilised hyaluronic acid injected to restore lost volume, refine contours such as the lips, chin and jawline, and soften deeper folds.
- Immediate result: volume is visible right after the session, with final settling over about two weeks.
- Temporary and biodegradable: the body gradually breaks the gel down, typically over 6–18 months depending on the product, the area and the individual.
- Reversible: uniquely among fillers, HA can be dissolved with an enzyme called hyaluronidase if ever needed — an important safety property.
- Tunable: HA gels come in different firmness levels ("rheology"). A soft gel suits lips; a firmer gel supports a cheekbone or jawline. Matching gel to anatomy is where medical training shows.
Calcium hydroxylapatite (CaHA) — volume plus collagen stimulation
Calcium hydroxylapatite (best known as Radiesse) is a thicker filler made of microscopic calcium-based spheres — the same mineral family found naturally in bone — suspended in a gel. It does two jobs: it lifts and volumises immediately, and over the following months it stimulates your own collagen production around the injected area.
- Well suited to deeper structural work: jawline definition, temples, hands and marked volume loss.
- Results typically last in the range of 12–18 months, varying by person and area.
- Not reversible with hyaluronidase — so precise placement by an experienced injector matters even more.
Poly-L-lactic acid (PLLA) — the gradual collagen builder
Poly-L-lactic acid (Sculptra) sits at the boundary between "filler" and "bio-stimulator". Rather than adding volume directly, it works by prompting your skin to build its own collagen over a series of sessions. The change appears gradually across weeks to months — which is exactly why many patients like it: no sudden change, just skin that slowly looks firmer and better supported.
Because PLLA is covered in depth in our article on collagen bio-stimulators, the short version here: it is a strategy for overall facial support and skin quality, not for shaping a specific line or lip.
What about permanent fillers?
Permanent or semi-permanent materials (such as PMMA or liquid silicone) still circulate in some markets. In our practice — and in the view of most academic dermatology — they are best avoided for facial aesthetics. The face keeps changing with age; a permanent implant does not. Complications, when they occur, are harder to treat and can appear years later. The modern standard is biodegradable, adjustable, and reversible where possible.
- HA fillers: immediate, temporary, reversible — the most versatile category.
- CaHA (Radiesse): immediate volume plus collagen stimulation; suited to structural areas.
- PLLA (Sculptra): gradual, collagen-driven improvement over months.
- Permanent fillers: generally avoided in evidence-based practice.
- Product choice follows anatomy and goal — decided in consultation, not before it.
How the choice is actually made
In consultation, the assessment comes before any product name: skin quality, bone structure, fat compartments, previous treatments and your medical history. Then the goal is defined — restore, refine, or support — and only then is a material and dose selected. Two patients asking for "cheek filler" may leave with two entirely different plans, and that is precisely the point.