# *Cross-linking.*

> What cross-linking means for hyaluronic acid fillers, why it determines firmness and durability, and how the choice of gel depends on the area.

- Source: https://www.vivaderm.de/lexicon-vernetzung-en.html
- Language: en
- Publisher: VIVA DERM, Privatpraxis für ästhetische Medizin, Rosastraße 6a, 45130 Essen, Germany, +49 1520 8367711
- Responsible physician: Katayoun Mostaghimi (Fachärztin für Allgemeinmedizin)
- Updated: 2026-10-05

Chemical linking of the hyaluronic acid chains. The stronger the cross-linking, the firmer and longer-lasting the gel.

## A closer look.

Natural hyaluronic acid is broken down in the body within one to two days. For a filler to last months, the long sugar chains are linked to each other with a cross-linker (usually BDDE). The resulting gel is more stable against enzymes and mechanical stress – and, depending on the degree of cross-linking, soft, medium or firm.

Firm, strongly cross-linked gels suit areas where structure is needed: chin, cheekbone, jawline. Soft, lightly cross-linked gels suit mobile or thin areas such as lips and tear trough. Non-cross-linked hyaluronic acid is used as a skin booster for hydration but lasts only a few weeks.

Cross-linking also affects dissolving: strongly cross-linked gels need more hyaluronidase or a second session. In licensed products the residual cross-linker is strictly limited; reactions to it are rare.

This lexicon entry is general information and does not replace the medical consultation required under German law (§ 630e BGB).

## At a glance.

- **Cross-linker:** usually BDDE
- **Soft gels:** lips, tear trough
- **Firm gels:** chin, cheeks, jawline
- **Non-cross-linked:** skin boosters

## Frequently asked questions.

**Is stronger cross-linking always better?**

No. A firm gel in the lips looks unnatural, a soft one on the chin disappears quickly. The fit to the area counts.

**Is the cross-linker dangerous?**

In licensed products the residual amount is minimal and strictly tested; intolerances are very rare.

## Related pages.

- [Hyaluronic acid](https://www.vivaderm.de/lexicon-hyaluronsaeure-en.html) – Lexicon
- [Chin with hyaluronic acid](https://www.vivaderm.de/hyaluron-chin-en.html) – Firm gel
- [Lips](https://www.vivaderm.de/lips-en.html) – Soft gel

## Sources

- [NHS: Dermal fillers – patient information](https://www.nhs.uk/conditions/cosmetic-procedures/non-surgical-cosmetic-procedures/dermal-fillers/)
- [MPDG – German medical devices act (fillers are medical devices)](https://www.gesetze-im-internet.de/mpdg/)
- [BfArM – Federal Institute for Drugs and Medical Devices](https://www.bfarm.de/)
- [DGPRÄC – German Society of Plastic, Reconstructive and Aesthetic Surgeons](https://www.dgpraec.de/)
- [§ 630e BGB – duty to inform before treatment (German Civil Code)](https://www.gesetze-im-internet.de/bgb/__630e.html)
- [DGBT – German Society for Aesthetic Botulinum Toxin Therapy](https://www.dgbt.de/)
- [AWMF – German clinical practice guidelines](https://www.awmf.org/)

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This page is general information and does not replace medical consultation and informed consent (§ 630e BGB). No guarantee of results. Prices are guide prices per GOÄ. Quoting with attribution (VIVA DERM, Essen) is expressly permitted.