In short. Most faces have a dominant side. When the deeper column is a lifelong habit pattern, and when a difference between the two sides needs investigating instead.
Key points
- The purpose of treating an asymmetric frown is to reduce the folding on the side that does more work, not to make the two sides equal.
- A plan that keeps the person’s own pattern produces a face that looks like them, with less creasing.
Almost nobody has a symmetrical glabella. One column is usually deeper, one brow usually sits a little higher, and the difference is most often a record of which side of the face does more work. The question worth asking is not whether the two sides match, but whether the difference has always been there.
Why one side usually works harder
Facial expression is not symmetrical. Most people have a dominant side that carries more of a squint and a frown, and the muscle on that side is used more often and can become bulkier. Sleeping on one side, chewing on one side and holding the head at an angle at a screen all add to the pattern.
The difference that is part of a face
A difference that has been present for as long as the person can remember, that appears in old photographs and that matches the asymmetry of the rest of the face is a feature of that face. It is worth knowing before treatment, because the aim is not to make the two sides identical. A face treated to perfect symmetry reads as wrong.
Treat the face, not the mirror image
The purpose of treating an asymmetric frown is to reduce the folding on the side that does more work, not to make the two sides equal. A plan that keeps the person’s own pattern produces a face that looks like them, with less creasing.
The difference that needs investigating first
A difference that is new is a different matter. A crease that has developed on one side over weeks or months, a brow that has dropped on one side, a lid that no longer closes fully, numbness or weakness of the face all point away from the skin and towards the nerve that supplies the muscles of the face. Those findings need a doctor rather than an aesthetic assessment, and sooner rather than later.
Treating an asymmetry honestly
Where the difference is long-standing and ordinary, the aim is a face that moves and rests the way it always has, with less folding on the side that works harder. Where the difference is new, the treatment question waits until the cause is known. The one plan that is never right is a plan that treats both sides as though they were the same.
Asymmetry that needs a doctor
- A difference that has developed over weeks or months rather than being present for years.
- A brow or an eyelid that has dropped on one side, or an eye that no longer closes fully.
- Weakness, numbness or a change in vision on one side, which needs urgent assessment.
How the two sides are compared in an examination is described in how frown lines are assessed. The anatomy that makes the creases vertical is set out in why frown lines are vertical, and what the brow does when the muscles are quiet is covered in the brow position trade-off.
Frequently asked questions
Is it normal for one glabellar line to be deeper than the other?
It is the usual finding. Facial expression is not symmetrical, most people have a dominant side that carries more of a squint and a frown, and the muscle on that side is used more often and can become bulkier. A difference that has been there for years and that matches the rest of the face is a feature of that face rather than a problem in it.
Should treatment aim to make the two sides match exactly?
No, and aiming there does not produce the better result. A face treated to perfect symmetry reads as wrong, because no face is symmetrical to begin with and the muscles are not working equally either. The aim is to reduce the folding on the side that does more work while keeping the person's own pattern intact.
What would make a one-sided change worth investigating?
Its timing. A difference that has developed over weeks or months, rather than being present for years, belongs with a doctor. So does a difference that comes with a brow or lid that has dropped, with weakness or numbness on one side of the face, or with any change in vision. Those findings point away from the skin and need assessing before anything cosmetic is considered.
Risks & Limitations
- Relaxing the corrugator and the procerus also lifts the medial brow, and in a brow that already sits high that lift can become the complaint rather than the result.
- A drooping eyelid, double vision, or difficulty swallowing, speaking or breathing after an injection needs emergency care rather than a wait-and-see approach.
- Resurfacing carries a risk of pigment change and, rarely, of scarring, and its result is judged weeks after the last session rather than on the following morning.
- No rung removes a crease that is established in the skin. A line that is visible at rest usually softens, and any statement that promises more should be treated with suspicion.
When to Seek Care
- Difficulty breathing, chest pain, or difficulty swallowing or speaking after an injection needs emergency care immediately.
- A drooping eyelid, double vision, or an eye that will not close fully after treatment.
- Weakness or numbness on one side of the face, or a brow that has dropped on one side.
- A crease that has appeared or deepened over weeks rather than years, or any change in vision on one side.
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.