Key points
- Fillers differ not just by brand but by stiffness (G′), cohesivity and water uptake, which determine how much a gel lifts, spreads or swells.
- Thick skin, strong muscles or areas under constant pressure compress and reshape the gel, so the same gel gives different results on different faces.
- Location matters a great deal. A 2026 study found that at 12 weeks about 10% of the volume remained in the lips, compared with about 60% in the cheeks.
- A well-known brand placed in the wrong layer or used in the wrong area gives a worse result than an ordinary product that is well chosen and correctly placed.
1. Every gel has its own “personality”
A 2022 review in the International Journal of Molecular Sciences summarised the key properties that determine how a filler behaves in the skin:1
| Property | What it means | Effect in the face |
|---|---|---|
| G′ (stiffness) | How well the gel recovers its shape when compressed | High = good lift, suited to deep layers · Low = soft, suited to superficial layers |
| Cohesivity | How well the gel holds together as a single mass | High = holds its shape as a bolus · Low = spreads smoothly through the tissue |
| Water uptake (swelling) | How much more the gel expands after injection | High = may look overfilled or puffy at first |
| Degree of cross-linking | How tightly the hyaluronic acid chains are linked | High = firmer, longer-lasting, absorbs less water |
The authors also point out that even fillers with the same indication can differ several-fold in these values from brand to brand, and there is still no standardised measurement that allows fair comparison across brands.1 A 2024 laboratory study comparing 8 fillers likewise found that differences in manufacturing technology led to clear differences in swelling, cohesivity and particle size.2
2. Every person's tissue is different
Gel does not simply float in the face. It is compressed, stretched and moved by muscles every day. A 2024 paper in Polymers explains:
- In areas with thick skin and dense tissue, such as the chin or jawline, constant pressure flattens the gel, so a gel with good elasticity and shape recovery is needed.3
- In areas with ligaments and taut skin, such as the nasolabial folds or the tip of the chin, a gel that relies on cohesivity alone is a poor fit, because it looks soft, sags and does not spring back.3
- In areas under little pressure, such as the upper cheek, a highly cohesive gel holds its shape well.3
People with thin skin, thick skin, strong facial-expression muscles or a different bone structure therefore need different gels, even when the problems look similar.
The belief that “exercising a lot or having a fast metabolism makes filler disappear faster” is not yet backed by clear evidence. Factors with stronger evidence are the type of gel, the area treated and how much that area moves.
3. Location changes the result more than you might think
Khan and colleagues, publishing in Aesthetic Surgery Journal Open Forum in 2026, tracked volume after filler injection. For the face as a whole, 97% remained at 2 weeks, 77% at 4 weeks and 57% at 12 weeks. Individual areas differed widely: at 12 weeks the cheeks still retained about 60%, while the lips retained only about 10%.4
The lips move constantly as we talk, eat and smile, so visible volume falls faster than in the cheeks, which move less. These figures explain why the same person may feel that lip filler fades quickly while cheek filler is still there.
Note: volume measured from the outside is not the same as the gel still present in the face. MRI studies have detected gel for more than 2 years.5 This means some of the gel remains, but it has spread or flattened so that it no longer gives the same shape. Read more in Filler lasts longer than you think.
4. The layer and the injection technique
The same gel placed in different layers gives a different shape and a different degree of naturalness. A firm gel placed too superficially may feel lumpy or look full when you smile; a soft gel placed deep may not give enough lift. The G′ range commonly used in the face is roughly 100–500 Pa, depending on the area.3 In addition, the amount per injection point, the injection speed and the choice of needle or cannula all change how the gel spreads.
This is the heart of layered injection. Read more in our article on the 5 layers of facial anatomy.
5. How it looks and what the numbers say don't always match
The same Khan study found that satisfaction with facial appearance and the perception of looking younger remained significantly higher than the measured volume at 4 and 12 weeks.4 Put simply, a face that looks more balanced does not depend on volume alone, so topping up to be “as full as on day one” is not always the right goal.
How we choose fillers at Vinfinity
- Start from the problem and the layer, not the brand. We assess whether the issue lies in the bone structure, the deep fat, the superficial fat or the skin.
- Look at each person's actual tissue: skin thickness, muscle strength and how much the area moves.
- Match the gel properties to the job: stiffness, cohesivity and water uptake, which sometimes means using more than one type in the same face.
- Use less, then review. We assess the result after the swelling settles, at about 2 weeks, before deciding whether to add more.
- Record every treatment: gel type, volume and location, so the next plan can be more precise.
See filler prices and services on our Dermal Filler in Udon Thani and Prices pages.
References
- Fundarò SP, Salti G, Malgapo DMH, Innocenti S. The Rheology and Physicochemical Characteristics of Hyaluronic Acid Fillers: Their Clinical Implications. International Journal of Molecular Sciences. 2022;23(18):10518. doi:10.3390/ijms231810518
- Enright KM, Weiner SF, Durairaj KK, Gilardino MS, Nikolis A. Evaluation of the Hydrophilic, Cohesive, and Physical Properties of Eight Hyaluronic Acid Fillers: Clinical Implications of Gel Differentiation. Clinical, Cosmetic and Investigational Dermatology. 2024;17:89–101. doaj.org
- Yi KH, et al. Rheological Characteristics of Hyaluronic Acid Fillers as Viscoelastic Substances. Polymers. 2024;16(16):2386. doi:10.3390/polym16162386
- Khan S, Habarth-Morales TE, Voytik M, Davis H, Broach RB, Percec I. Short- and Long-Term Patient Perceptions Relative to Hyaluronic Acid Filler Volume Retention. Aesthetic Surgery Journal Open Forum. 2026. doi:10.1093/asjof/ojag030
- Master M, Azizeddin A, Master V. Hyaluronic Acid Filler Longevity in the Mid-face: A Review of 33 Magnetic Resonance Imaging Studies. Plastic and Reconstructive Surgery Global Open. 2024;12(7):e5934. doi:10.1097/GOX.0000000000005934
This article is for general education and is not personal medical advice. Always consult a doctor before deciding on any treatment.