Facial asymmetry: what can be treated, and what should be left alone

It starts in development

The two halves of your face grow from separate populations of cells, driven by the same genes acting independently on each side. Perfect symmetry would be the anomaly rather than the norm. Studies that set out to measure facial symmetry find measurable deviation in essentially every face examined, and the amount most people carry sits comfortably inside what anyone would call normal.

It is worth holding onto that, because the mirroring trick that makes asymmetry so visible is a distortion. Doubling one half of your face produces something no human being has ever looked like, then invites you to compare yourself to it.

And it increases with age, fairly predictably

Bone resorbs unevenly. Fat pads descend at different rates on each side. Decades of chewing on a preferred side, sleeping on a preferred side and expressing more strongly on one side all leave their mark on the tissue.

Someone who has always slept on their right side often has a flatter right cheek by fifty. That is not a defect that appeared — it is a difference that became visible. Which is also why a small correction earlier tends to work better than a large one later.

The practical point is that a small asymmetry is not evidence that something has gone wrong. It is evidence that you have a face.

Almost every disappointing outcome in this area comes from treating the wrong cause. The four behave completely differently, they are distinguishable in a five-minute assessment, and only two of them respond well to injectables.

Why the distinction is not academic

A muscular asymmetry treated as though it were volume loss gets filler added to a side that did not need it, and the difference is preserved at a larger size. A skeletal asymmetry sold as fully correctable produces a patient who keeps returning for more product chasing a result that was never available.

Both are common. Both are assessment failures rather than product failures, and both are avoidable in the first appointment.

This is the most important section on the page, and it applies to a small number of readers who need it urgently.

• SUDDEN facial droop, especially with arm weakness or slurred speech — call 999. That combination is the FAST test for stroke and it does not wait for an appointment.
• Asymmetry appearing over hours to days, usually one-sided, often with the eye on that side not closing fully — a GP or urgent care the SAME DAY. This is more likely a facial palsy such as Bell's palsy, treatment works considerably better started early, and an eye that cannot close is at real risk.
• Progressive asymmetry, or asymmetry with pain, numbness or a lump — a GP, before anything cosmetic.

The asymmetry this page is about is the kind you have had for years, that has crept up gradually with age, or that you noticed in a photograph and have not been able to stop seeing since.

It depends entirely on which of the four causes is behind it, and that is a five-minute assessment rather than a guess from a photograph.

If it is muscle

One masseter being stronger and bulkier than the other is common, and it is the most satisfying version of this problem to treat. Relaxing the stronger side reduces its bulk over two to three months and the jaw reads more even from the front. The change is gradual and it holds better with repeat treatment.

If it is bone

Where the mandible itself sits differently, filler along the weaker side improves how the jawline reads and will not make the two sides match. That is worth hearing before you spend rather than after.

The mistake to avoid

Treating both sides equally because it feels fairer. Symmetrical dosing on an asymmetric jaw preserves the asymmetry at a larger size, and it is the most common way this treatment disappoints people.

Extremely common, and usually a mixture of two things: a genuinely different vermilion shape on each side, and a muscular pull that lifts one corner more when you smile.

Telling the two apart takes ten seconds

Look at your lips at rest, then smiling. Uneven at rest and even when smiling is a shape problem, and shape responds to filler — deliberately more on one side than the other. Even at rest and uneven when smiling is muscular, and adding filler to it will not help.

The trap

Chasing the last few percent of evenness with more product. Tissue can only accommodate so much before it stops holding shape and starts holding pressure, and pressure is what pushes filler upward past the border — which is migration.

Every millilitre added in pursuit of perfect symmetry raises that risk, and the last few percent is the part nobody else can see anyway.

Brows and eyes

This is where a small change reads largest, because the brows frame everything above the nose. A brow sitting lower on one side is often muscular — the depressors on that side pulling harder — and relaxing them selectively can lift it a few millimetres. A few millimetres is a great deal on a brow.

An under-eye looking hollower on one side is frequently not a volume difference at all, but a shadow cast by the orbital rim, or pigmentation. All three look identical in a bathroom mirror and need completely different treatments. This is the single most over-treated area in aesthetics and it is worth an assessment before it is worth a syringe.

Chin

Usually skeletal. Filler placed to the deficient side improves projection and can bring the chin point visually closer to centre, and it is often the treatment that changes a profile most for the least product. It will not straighten the bone, and a plan promising that is not one to buy.

The question nobody answers, and the one worth asking before you book anything.

A plan that does not tell you which row you are in is not a plan. If nobody has said out loud which part of what bothers you is treatable and which part is not, you have not had an assessment.

1. Looking at you still and moving, from the front and in profile, and asking you to smile, raise your brows and clench — because a difference that only appears on movement is muscular and one present at rest usually is not.
2. Asking how long it has been there. Longstanding and gradual points one way; recent points to the red flags above and changes the appointment entirely.
3. Photographs in consistent lighting, which matter more here than anywhere else — a phone camera held close reliably invents asymmetry that is not there.
4. A plan that is explicit about which part is treatable, which part is skeletal and is not, and roughly how much of the difference is going to change.

Correcting asymmetry is harder than adding volume, it takes more assessment, and it is the work where the gap between a careful injector and a fast one shows most clearly. It is also the work where the temptation to keep going is strongest, because there is always a little more that could be evened out.

The trap worth naming

Once someone starts photographing their own face looking for asymmetry, they will find it — and finding it makes it more visible to them and to nobody else. Several people a year would be better served by being told that what they are describing is within normal variation than by being sold a plan to fix it. That is a conversation rather than a treatment, and it is free.

And some asymmetry is worth keeping

Correcting it can cost you something you would miss. A smile that pulls slightly to one side is often the thing people who love you would name first if asked to describe your face.