> For the complete documentation index, see [llms.txt](https://docs.saas.haut.ai/haut.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.saas.haut.ai/haut.ai/haut.ai-features/algorithms/face-skin-analysis-3-0/lines/glabellar-lines.md).

# Glabellar Lines

What the Glabellar Lines parameter measures between the eyebrows, why frown lines form, and how to read the grades it returns.

## About Parameter

Glabellar lines, often called frown lines, are the small vertical wrinkles that appear between your eyebrows. They form when the muscles that pull your eyebrows together move repeatedly — for example, when you frown or concentrate. At first, these lines show up only during facial expressions, but over time, they can become visible even when your face is relaxed.

## Features

1. Works with 1 and 3 side facial images.
2. Evaluates severity (grade) of glabellar lines
3. Separates and segments deep and fine lines

## Output

1. Grade from 1 to 5.
2. Vector mask for deep lines.
3. Vector mask for fines lines.
4. Vector mask containing both deep lines and fine lines.
5. Algorithm-assigned skin condition tag (Great, Good, Average, Poor).
6. Amount of lines.
7. Amount of deep lines.
8. Amount of fine lines.
9. Length of lines relative to length of the forehead.
10. Length of deep lines relative to length of the forehead.
11. Length of fine lines relative to length of the forehead.

Note: When a single line has varying severity (containing both deep and fine sections), it is categorized as a one deep line rather than a fine line.

## Grades Description

Severity assessment based on the depth of the most prominent wrinkle

<table><thead><tr><th width="120.4296875">Grade value</th><th width="484.68359375">Description</th><th>Tags</th></tr></thead><tbody><tr><td>1</td><td>No visible wrinkles</td><td>Great</td></tr><tr><td>2</td><td>Fine, shallow wrinkle that is barely noticeable</td><td>Good</td></tr><tr><td>3</td><td>Prominent wrinkle that is deeper and wider with a visible base</td><td>Average</td></tr><tr><td>4</td><td>Deep, clearly defined wrinkle with raised borders on both sides (slightly or moderately pronounced)</td><td>Poor</td></tr><tr><td>5</td><td>Deep wrinkle with prominent raised borders, creating the impression of "carved" skin in this area</td><td>Poor</td></tr></tbody></table>

## Algorithm API

{% hint style="warning" %}
API access is available only for <mark style="color:purple;">**Professional**</mark> plan clients
{% endhint %}

See [Glabellar Lines Parameter Result Scheme](/haut.ai/developers/saas-api-overview/api-for-face-skin-analysis-3.0/lines/glabellar-lines.md).

***

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---

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