Types of Fillers: How Do They Differ by Ingredient? A Complete Guide to HA, CaHA, PLLA, and PCL

Fillers are classified according to their primary ingredient into hyaluronic acid (HA), calcium hydroxylapatite (CaHA), poly-L-lactic acid (PLLA), polycaprolactone (PCL), polymethyl methacrylate (PMMA), and autologous fat. Each type has a different mechanism of action and longevity. Among these, hyaluronic acid fillers are the most common choice, accounting for 80–90% of the global market, and they are the only fillers that can be dissolved and reversed using an enzyme called hyaluronidase.

Therefore, if you are considering fillers for the first time, rather than asking "Which product lasts the longest?", you should first ask, "Which ingredient is right for my treatment area and situation?" A longer-lasting filler is not necessarily a better filler. Below, we break down the differences between each ingredient one by one.

🧬 What Are Fillers, and Why Are There So Many Types?

Dermal fillers are an invasive medical procedure injected beneath the skin to restore lost volume or smooth wrinkles. It is important to note first that this is not a topical cosmetic, but an act of introducing material into tissue using a needle or cannula.

The global dermal filler market is projected to reach approximately $5.05 billion in 2025 and grow to $9.3 billion by 2034 (a CAGR of 7.21%). Due to high demand, ingredients and formulations have continually diversified, providing a wider range of choices.

The reason there are so many types is simple: fillers that instantly fill volume and fillers that stimulate collagen production over time have fundamentally different mechanisms of action. The former takes shape immediately, while the latter gradually restores volume.

📌 Key Takeaway: Fillers are invasive medical procedures with varying mechanisms of action and longevities depending on their ingredients, largely divided into immediate volumizing types and collagen-stimulating types.

💉 Comparing Types of Fillers by Ingredient at a Glance

The duration and characteristics by ingredient are summarized below. The figures are reference ranges and may vary depending on the individual, treatment area, and formulation.

Hyaluronic Acid (HA) — The Most Common and Reversible

Because HA is a component naturally present in our skin, it has high biocompatibility and is widely used across delicate areas like the lips and under-eyes to areas requiring structural support like the bridge of the nose and the chin. The viscoelasticity of the formulation is controlled through cross-linking technology; tighter cross-linking results in a firmer, longer-lasting product.

The greatest advantage is that if an issue occurs, it can be dissolved and corrected with hyaluronidase. For this reason, recommending HA first to first-time patients is the consensus across almost all clinical practices.

CaHA — Structural Support Resembling Bone Minerals

CaHA is formulated to be similar to hydroxyapatite, a bone component, providing excellent structural support. It provides an immediate volumizing effect upon injection while simultaneously offering a dual effect of inducing collagen biostimulation. A prominent product line is Radiesse.

PLLA — Collagen-Stimulating Type That Fills Gradually

Rather than filling volume directly on its own, PLLA works by stimulating fibroblasts to increase collagen. Sculptra and Juvelook are representative examples, and achieving desired results typically requires 2 to 4 or more repeated sessions. It is an ingredient that may disappoint those expecting immediate changes.

PCL — Choosing Longevity from 1 to 4 Years

With PCL (Ellansé), longevity can be selected from 1 up to 4 years depending on the formulation type (S/M/L/E). Because it also belongs to the collagen-stimulating family, results take shape gradually.

PMMA and Autologous Fat — Options Requiring Caution

Because PMMA is a semi-permanent to permanent material, it is virtually impossible to remove once injected. Thus, it is an ingredient that must be approached with great care. Autologous fat grafting is a surgical procedure utilizing the patient's own fat, and according to literature, the survival rate varies widely at around 30–70%.

📌 Key Takeaway: HA is reversible and widely used; CaHA, PLLA, and PCL stimulate collagen; PMMA and autologous fat are difficult to remove and require caution.

⏳ Is a Longer-Lasting Filler Always Better?

Many people say, "If I'm getting it done, I'd rather choose one that lasts a long time," but there is a pitfall here. The longer the duration, the harder it is to reverse if a problem arises.

While HA can be dissolved, CaHA, PLLA, PCL, and PMMA cannot be enzymatically broken down. This means that if it settles into an awkward position or side effects occur, one often has to wait for natural absorption. This is why for irreversible options, practitioner expertise and accurate anatomical assessment become even more critical.

Additionally, if filler accumulates through repeated procedures, the face can appear unnaturally heavy—the so-called overfilling issue. Onlif pursues a clear philosophy: without altering your natural expression, subtly refining only the sunken areas. A good procedure is about injecting the appropriate amount, not injecting a lot.

📌 Key Takeaway: Long-lasting fillers are difficult to correct and carry accumulation risks, so choices should be guided by 'natural results and safety' rather than 'longevity.'

🎯 Which Filler Is Right for Each Area?

Each facial area requires a different viscosity and softness. Here is a general guideline:

• Lips and Under-Eyes (Tear Troughs): Soft HA is suitable. Superficial injection can lead to the Tyndall effect, where the product looks bluish through the skin, making depth control crucial.

• Nasolabial Folds: Medium-viscosity HA is used to restore natural volume.

• Chin and Nose Bridge: Require structural support, so high-viscosity HA or CaHA is considered.

• Cheeks and Zygomatic Area: Areas requiring volume restoration across a wider surface.

At Onlif, we also handle treatments requiring delicate control, such as lip fillers and nasolabial fold fillers. Even with the same HA filler, the formulation and depth must be tailored to the area to achieve natural results.

For reference, nose filler is a non-surgical option to refine contours, but it is a high-risk area dense with blood vessels. There are limitations if the goal is to significantly alter the underlying shape, so it is advisable to clarify your goals first and coordinate them during your consultation.

📌 Key Takeaway: Soft HA is suitable for the lips and under-eyes, while high-viscosity HA or CaHA is appropriate for the chin and nose bridge; adjusting depth and formulation by area determines natural results.

⚠️ Side Effects and Safety to Keep in Mind

The most serious risk to watch for with fillers is vascular occlusion. Although rare, it is a severe complication that can lead to skin necrosis or vision impairment, and the nose, glabella, forehead, periorbital area, and nasolabial region are high-risk zones. If symptoms such as severe pain, skin blanching or turning purplish, or visual disturbances appear after the procedure, you must contact a medical facility immediately. Timely response within the golden window is essential.

In a 2020 survey of 254 domestic medical professionals, 42% ranked 'safety' as the top consideration for filler procedures, surpassing 'efficacy.' This demonstrates that clinical practitioners prioritize safety above all else.

This is why the practitioner's anatomical understanding and skill level are critical. Onlif operates under a physician specialty system, rooted in the belief that "no single doctor can excel at everything." It is a structure where physicians take charge of the specific treatments they perform best.

Always verify product authenticity as well. In Korea, fillers must be approved by the Ministry of Food and Drug Safety (MFDS), and many formulations include lidocaine to reduce pain during the procedure.

📌 Key Takeaway: Vascular occlusion is rare but severe, demanding extra caution in high-risk areas; MFDS-approved products and experienced practitioners are central to safety.

🔄 Fillers and Botox Are Different Procedures

These two are often confused, but they are completely different. Fillers restore volume to sunken areas, while botulinum toxin (Botox) relaxes muscle movement. Botox is used for dynamic expression lines, and fillers are used for hollowed volume.

Therefore, the two are frequently combined. However, the appropriate areas, sequence, and dosage vary depending on individual condition, so they should be determined through a consultation rather than self-assessed.

Beyond fillers and Botox, non-surgical approaches for skin laxity include thread lifts, ultrasound HIFU, and radiofrequency (RF). Even if an area appears 'sunken,' the solution differs depending on whether the cause is volume loss or decreased elasticity. Fillers are not always the answer.

📌 Key Takeaway: Fillers restore volume while Botox inhibits muscle movement; for sagging and loss of elasticity, other non-surgical options like lifting or HIFU may be more appropriate.

❓ Frequently Asked Questions (FAQ)

If I am getting fillers for the first time, which type is safest to start with?

Hyaluronic acid (HA) fillers are often recommended first because they can be adjusted and reversed. If you are dissatisfied with the outcome or an issue occurs, the burden is low because they can be dissolved with hyaluronidase.

Can fillers be dissolved? Which fillers can be dissolved?

Only HA fillers can be dissolved using the enzyme hyaluronidase. CaHA, PLLA, PCL, and PMMA cannot be dissolved enzymatically, so one must wait for natural absorption or consider other interventions.

Is a longer-lasting filler always better?

Not necessarily. The longer the duration, the harder it is to correct or remove, making complications or awkward positioning difficult to manage. Natural results and safety are far more important criteria.

What should I be particularly careful about with under-eye fillers?

Because the skin is thin, superficial injection can cause the Tyndall effect, creating a bluish tint. This area requires delicate technique to place a soft formulation at the appropriate depth.

Are there any medications I should stop taking before a filler procedure?

Anticoagulants, aspirin, and omega-3 supplements can increase the risk of bruising and bleeding, so it is best to disclose them in advance. Please share any medications you are taking and your overall health status during your consultation.

When do bruising and swelling typically subside?

Swelling usually subsides within 3 to 7 days, and bruising generally resolves within 1 to 2 weeks. Because the final result is best evaluated around 2 weeks post-procedure, we recommend receiving treatment at least 2 weeks, and preferably 3 to 4 weeks, before important events.

Things to Check Before Choosing a Clinic for Fillers

Even for the same procedure, results and recovery vary depending on where, by whom, and how it is performed. Asking the following questions during your consultation will help guide your decision:

• Does the clinic perform this procedure frequently? — Every clinic has different core specialties. Check whether they regularly perform filler treatments.

• Can you verify the products and equipment used? — Inquire whether you can confirm the product name and authenticity (such as import approval status and package unsealing verification) during your consultation.

• Do they explain the cost breakdown? — Rather than just hearing a total price, you need an explanation of which product is used, how much is injected, and across what areas to make an informed judgment.

• Do they design the treatment considering the entire face? — Even for the same procedure, injection sites and volume vary based on facial shape, skin condition, and bilateral asymmetry.

• Do they explain adverse reactions and recovery beforehand? — A clinic that discusses potential side effects and management strategies alongside expected outcomes is preferable over one that only promises positive changes.

• Is there a clear follow-up process after the procedure? — Check whether follow-up check-in timelines, contact methods in case of abnormalities, and criteria for return visits are clearly established.

How Onlif Clinic Approaches Fillers

• We assign dedicated specialists — Believing that no single physician can master every procedure, Onlif assigns dedicated doctors tailored to specific treatment areas.

• We verify products and equipment together during consultation — We guide you through the products used and our unsealing verification process during your consultation.

• Costs are explained with full details after assessment — Because treatment areas, dosages, and coverage vary per person, we provide a transparent breakdown of what is required and how much it costs.

• We design treatments around overall facial harmony — Viewing the face through the three pillars of texture, balance, and youthfulness, we plan treatments to refine areas that obscure your innate expression rather than altering your facial structure.

• We discuss potential adverse reactions and recovery first — Along with expected improvements, we explain individual variations, potential side effects, and management protocols prior to treatment.

• We monitor your post-procedure progress together — If follow-up evaluation is needed during recovery, we provide guidance on revisits and dedicated communication channels.

If you are considering fillers, it is best to first understand what is achievable and what is limited given your current condition. An accurate assessment and treatment plan can only be made through an in-person consultation. Visit Gangnam Onlif Clinic for a personalized consultation.