In short. A high-movement area creases along the same lines thousands of times a day. Why that makes perioral lines different from a fold caused by lost volume.
Key points
- Look at your upper lip in a mirror, then purse your lips firmly as though about to whistle.
- The lines that appear and deepen with the movement are the ones this muscle produces.
- The ones that are still visible when the lips are relaxed have something set in the skin as well, and that part will not be changed by addressing the muscle.
The muscle that rings the mouth is a circle of tissue that closes the lips and shapes almost every sound a person makes. It contracts constantly, and each contraction folds the skin above and below the lip along the same radial lines. That combination of frequency and repetition is why lines appear here early.
How often the skin is folded
Speaking, eating, drinking, kissing, whistling, smiling and thinking all involve this muscle. Some of those actions happen hundreds of times a day, and the skin above the lip is folded in the same places every time.
Why the lines run the way they do
The muscle is a ring, so its fibres run around the mouth rather than across it. Skin folds perpendicular to the direction of the muscle, so the resulting lines radiate outwards from the mouth and read as vertical lines above the upper lip. Lines that run in another direction, or that form a fine mesh rather than distinct creases, are usually about hydration or sun instead.
The demonstration takes five seconds
Look at your upper lip in a mirror, then purse your lips firmly as though about to whistle. The lines that appear and deepen with the movement are the ones this muscle produces. The ones that are still visible when the lips are relaxed have something set in the skin as well, and that part will not be changed by addressing the muscle.
Why a movement line behaves differently
A line produced entirely by muscle is reduced when the movement is reduced. A line that is set in the skin is not. Most mouths past a certain age have both in the same crease, which is why the honest expectation after treating the muscle is a softening rather than a disappearance.
Why this muscle is treated carefully
It is not only an expressive muscle. It closes the lips, it shapes speech, and it helps keep food and drink where they belong. Treating the area aggressively in pursuit of smoother skin risks changing those functions, which is why the approach here is conservative.
What this contributor does not explain
It does not explain a blurred lip border, a mouth that looks smaller or flatter than it used to, or a shadow beside a corner that has turned down. Those have other causes, and reducing movement addresses a contributor that may not be the one producing the appearance that bothers the patient.
When a change around the mouth is not a line
- A one-sided change, or numbness, tingling or loss of sensation in the lip or chin.
- A sore, ulcer or crust that has not healed within a few weeks, or that bleeds.
- Sudden deep fissuring with swelling and soreness, or a recurring blister in the same place.
How lost volume changes the way the mouth folds is set out in Volume Loss and the Lip Border. How the contributors are separated at an examination is described in How Perioral Lines Are Assessed.
Frequently asked questions
Why do these lines appear earlier than lines elsewhere on my face?
Because the muscle around the mouth is among the most used in the face. It contracts with every word, sip, kiss and expression, so the skin is folded along the same radial lines far more often than the skin on the cheek or the temple. Frequency of folding matters, and this area folds more than almost anywhere else.
Are the lines always vertical?
The lines produced by this muscle run radially, radiating outwards from the mouth, which is why they read as vertical above the upper lip. Lines that run in a different direction, or a fine mesh rather than distinct creases, are more likely to be about hydration or sun damage than about the muscle, and they respond to different things.
Does relaxing the muscle affect how I speak or eat?
It can, which is why the area is treated conservatively. The muscle has several jobs beyond making expressions: it closes the lips, it shapes sounds, and it helps control food and drink in the mouth. A cautious approach reduces the movement that causes the lines while leaving those functions as they were, and it is why this area is not treated the way the forehead is.
Risks & Limitations
- Perioral lines have several contributors and none of the options erases them. Relaxing the muscle reduces movement, adding volume changes how the mouth folds, and resurfacing softens what is set in the skin. All of it needs maintaining.
- The lip border is a high-movement area with thin tissue and very little padding beneath it, so material placed there behaves differently from elsewhere in the face and the result depends on technique and on experience rather than on volume.
- Injectables carry risks that depend on the area treated and on the person placing them, including asymmetry, nodules and, rarely, vascular problems. Resurfacing carries downtime and a risk of pigment change that is greater in deeper skin tones.
- An active sore, an unhealed lesion, an infection or inflamed cracked corners are reasons to defer treatment, because injecting or resurfacing through them risks a problem being missed or made worse.
When to Seek Care
- A sore, ulcer or crust on the lip that has not healed within a few weeks, or that bleeds or recurs — have it examined.
- A change confined to one side of the lip, or numbness or altered sensation in the lip or chin — seek medical assessment first.
- Sudden deep fissuring with swelling and soreness, or a lip that has become swollen and stayed swollen — seek medical assessment.
- After any treatment: severe pain, blanching or mottled skin, a spreading dusky discolouration, or worsening swelling — seek urgent care.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.