What Are Dermal Fillers —
and How Do They Work?

Most people think fillers lift the face. They don’t. Dermal fillers are injectable substances placed beneath the skin to restore volume, smooth lines, or refine facial contours. Lifting is what devices do — Ultherapy, Thermage. Fillers add substance where the face has lost it, or define structure where it was always subtle.

The most widely used are hyaluronic acid (HA) based — a substance naturally present in the body. HA fillers attract water, creating volume that feels soft and natural. They’re also reversible: a medical enzyme called hyaluronidase dissolves them rapidly if adjustment is needed. That reversibility is why HA fillers are the global standard, not a preference.

Korean face filler practice differs from much of the Western market in one key way: the emphasis is on structural harmony rather than volume addition. The goal isn’t to look filled — it’s to restore what was there. That distinction drives product selection, injection depth, and the amount used per area.

Filler Types —
What’s Actually Used in Korea

Not all fillers are the same substance. The major categories differ in how they work, how long they last, and what they’re best suited for. These are the main brands used at Yaan Clinic — all FDA and KFDA cleared.

Yaan Clinic also offers Skin Plus-Hyal — a semi-permanent HA-based filler lasting approximately 3 years while remaining dissolvable. For patients who want longer duration without committing to a permanent product. Full guide at Post 04: Skin Plus-Hyal →

Treatment Areas —
What Fillers Solve Where

Fillers are versatile — but not universal. Each area has different structural requirements, preferred products, and realistic outcome expectations. The table below reflects what’s actually achievable, not the best-case scenario.

For a detailed comparison of which filler works best for each specific concern, see Post 02: Which Filler for Which Area? →

Safety Protocol —
What Professional Clinics Do Differently

• 1

  Infrared vascular mapping

  Before injection in any high-risk zone (nose, glabella, nasolabial folds), the vein finder maps blood vessel location in real time. The injection plan is adjusted around what’s visible — not assumed from anatomy alone.

• 2

  Micro-cannula technique

  Rounded-tip cannulas are used instead of sharp needles for most treatment areas. The rounded tip glides through tissue rather than cutting — significantly reducing bruising, swelling, and the risk of accidental vascular penetration.

• 3

  Authenticated products only

  Only genuine FDA and KFDA-cleared fillers are used at Yaan Clinic — all from verified distributors. Counterfeit or grey-market fillers are a real issue in the Korean aesthetic market. Patients can request product authentication documentation.

• 4

  Reversibility confirmation

  For HA fillers: hyaluronidase is available on-site for immediate use if adjustment is needed. Patients are informed of this before treatment. Dissolving HA filler when needed — not waiting — is standard protocol, not an exception.

What to Expect —
The Realistic Picture

Filler results are immediate but not final. Swelling from the injection itself peaks at 24–48 hours, then resolves over 1–2 weeks. The shape you see immediately after treatment isn’t the final result — wait 2 weeks before judging.

• Results timeline

  Immediate: visible volume change. Day 1–3: peak swelling — result looks slightly more than intended. Week 1–2: swelling resolves, filler integrates with tissue. Week 2+: final result. Most patients feel confident going out immediately but know the real result comes two weeks later.

• How long results last

  Lips: 6–9 months (high movement area). Cheeks and jawline: 12–18 months. Temples and nose: 12–18 months. Nasolabial folds: 12 months. Radiesse areas: 12–24 months. Skin Plus-Hyal: approximately 3 years. Individual metabolism affects duration — faster metabolizers break down filler sooner.

• What fillers can’t do

  Fillers restore volume and define contours — they don’t tighten skin or lift structural tissue. For sagging jawline or laxity, lifting devices (Ultherapy Prime, Thermage FLX) address what fillers cannot. Many patients combine both: filler for volume, lifting for structure. See the full comparison at Post 02 →

Frequently Asked
Questions

What are the most popular dermal fillers used for facial rejuvenation?

The most widely used are hyaluronic acid fillers — Restylane and Juvederm — and calcium hydroxylapatite (Radiesse). HA fillers work immediately, last 12–18 months, and are reversible. Radiesse stimulates collagen and lasts longer. At Yaan Clinic, Dr. Wontak Choi is a certified Key Doctor for both Restylane and Radiesse — among the highest clinical designations globally for these products.

What is the difference between temporary and permanent facial fillers?

Temporary fillers (HA, Radiesse) are absorbed by the body over 12–24 months and can be dissolved or adjusted. Permanent fillers can’t be removed without surgery. Most specialists recommend temporary fillers because facial structure changes over time. Skin Plus-Hyal is a semi-permanent option lasting 3 years that remains dissolvable — the best of both approaches.

Which hyaluronic acid fillers have the longest-lasting effects?

Longevity depends more on treatment area than product. High-movement areas (lips) break down filler faster — 6–9 months. Low-movement areas (cheeks, temples) last 12–18 months. Restylane Lyft and Juvederm Voluma are formulated for deeper placement and longer duration. Skin Plus-Hyal lasts approximately 3 years while remaining dissolvable.

What are the most effective fillers for under-eye hollow correction?

Tear trough correction requires a soft, low-viscosity HA filler placed precisely in the groove — technically one of the most demanding filler zones. Too superficial causes bluish discoloration (Tyndall effect); too deep misses the target. At Yaan Clinic, infrared vascular mapping is used before injection and micro-cannulas minimize bruising in this sensitive area.

Can dermal fillers be removed if I don’t like the results?

HA fillers dissolve rapidly with hyaluronidase — a medical enzyme injected at the clinic. Results of dissolving are visible within 24–48 hours. Radiesse is not dissolvable but naturally absorbed over time. Skin Plus-Hyal, despite lasting 3 years, remains dissolvable throughout. At Yaan Clinic, hyaluronidase is kept on-site for immediate use if adjustment is needed.