# Expression *lines.*

> Expression lines explained: how they arise from muscle activity, difference to static lines, the mirror test, treatment with botulinum toxin and limits.

- Source: https://www.vivaderm.de/lexicon-mimische-falten-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

Lines created by repeated muscle movement – frown lines, forehead lines, crow's feet. The domain of botulinum toxin.

## A closer look.

Expression (dynamic) lines form where a muscle folds the skin into the same crease for years: when frowning, squinting or smiling. At first they disappear as soon as the muscle relaxes; over time the skin 'remembers' the line because collagen and elastin fatigue at that spot.

The simple test: relax the face completely and look in the mirror. If the line disappears, it is dynamic – here botulinum toxin works by resting the muscle for months. If it stays, it is (also) static and needs volume or skin quality.

Typical dynamic areas are glabella, forehead, crow's feet, bunny lines and the chin crease. Treated early, the dynamic line is prevented from becoming static; that is the core of so-called prevention – sensible only once the line starts to remain at rest.

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

## At a glance.

- **Cause:** muscle movement
- **Test:** disappears when relaxed
- **Treatment:** botulinum toxin
- **Areas:** glabella, forehead, eyes, nose, chin

## Frequently asked questions.

**Are expression lines treated with hyaluronic acid?**

Usually not; hyaluronic acid is broken down quickly if the muscle keeps working. Botulinum toxin first, then volume if needed.

**Do they disappear permanently?**

No. Once the effect wears off, movement returns; regular treatment prevents deepening.

## Related pages.

- [Botulinum toxin](https://www.vivaderm.de/botox-en.html) – Treatment
- [Static lines](https://www.vivaderm.de/lexicon-statische-falten-en.html) – Lexicon
- [Botox or filler?](https://www.vivaderm.de/guide-botox-or-filler-en.html) – Guide

## Sources

- [NHS: Botox injections – patient information](https://www.nhs.uk/conditions/cosmetic-procedures/non-surgical-cosmetic-procedures/botox-injections/)
- [DGBT – German Society for Aesthetic Botulinum Toxin Therapy](https://www.dgbt.de/)
- [BfArM – Federal Institute for Drugs and Medical Devices](https://www.bfarm.de/)
- [European Medicines Agency (EMA)](https://www.ema.europa.eu/)
- [§ 630e BGB – duty to inform before treatment (German Civil Code)](https://www.gesetze-im-internet.de/bgb/__630e.html)
- [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.