Key takeaways
- Smile lines are normal anatomy. Even children have them when they smile.
- They often deepen because the cheek above has lost volume or support, not because the line itself is "empty".
- Filling the fold directly can help, but overfilling flattens the face and looks unnatural.
- Rapid weight loss commonly deepens these folds.
- Leaving them alone is a perfectly reasonable choice.
Why do smile lines get deeper?
People come in, point to these lines and ask me to "fill them up". I understand. But I ask them to look in a mirror held below their face, then lie back.
See, what happens is, the nasolabial fold is where the cheek meets the upper lip area. When you are young, the cheek is full and sits high, and the fold is soft. With age, the cheek fat shrinks and slides a little, the bone underneath remodels, and the skin loses firmness. The weight of the cheek then sits on the fold, and the fold looks deeper.
So the line is often a symptom of what is happening above it. That is very important to understand, because it changes the treatment.
Rapid weight loss can do the same thing quickly. Dermatology Times describes deeper nasolabial folds, drooping cheeks and hollowing after medicine-assisted weight loss, from loss of supporting fat.
What are my options?
| Approach | What it does | Suits | Watch out for |
|---|---|---|---|
| Leave them | Nothing | Anyone who is not bothered | Nothing, except sunscreen still matters |
| Support the cheek | Small amounts of hyaluronic acid filler placed higher, in the cheek | Folds deepened by cheek volume loss | Too much makes the cheek look heavy |
| Fill the fold | Hyaluronic acid filler placed along the line | Deep creases with good cheek support | Overfilling, a "puffy" mid-face, serious vascular risk |
| Tighten the skin | HIFU or radio frequency to firm skin over months | Mild laxity | Gradual, modest change |
| Thread lift | Lifts and supports soft tissue | Selected mild cases | Temporary |
All of these are available at our centres. Often the plan is a combination of small steps rather than one large one.
Filling the fold: when is it right?
The US FDA lists nasolabial folds among the approved uses for absorbable, temporary fillers. Mayo Clinic notes hyaluronic acid fillers usually need one to three sessions and repeating after some months.
Normally I fill the fold directly when: - The cheek support is reasonable - The crease is deep enough to catch shadows - The person wants a subtle softening, not erasure
I do not try to make the fold disappear. A face with no smile lines at all looks strange when it smiles. Basically, the aim is a softer shadow.
Supporting the cheek instead
When the cheek has flattened, a small amount of support in the cheek can lift the tissue a little and soften the fold more naturally than filling the line. I explain this more in cheek and jawline fillers. The trap is going too far. Many "overfilled" faces come from repeatedly filling folds and cheeks, a little more every time, until the mid-face is heavy. I wrote about this in why some faces look overdone.
What are the risks of fillers here?
The area around the nose and mouth has important blood vessels. The US FDA lists accidental injection into a blood vessel as the most serious filler risk. It can block blood flow and cause skin damage, and rarely vision problems or stroke. Common effects are bruising, swelling, redness and tenderness, which usually settle.
What I tell people: - Choose a qualified doctor who knows facial anatomy. - Ask which product is being used and how much. It should be written down. - Never buy filler online or let anyone inject you at home or a salon. The FDA warns against both. - Seek urgent care for severe pain, skin turning white, grey or blue, or any change in vision after treatment.
Hyaluronic acid fillers can be dissolved with an enzyme if needed, which is one reason I use them over fillers that cannot be reversed.
What about tightening instead of filling?
For mild softening of the lower face, energy-based treatments such as HIFU and radio frequency can firm skin gradually by stimulating collagen. A 2026 review of microfocused ultrasound found the evidence supports it for mild to moderate laxity. They will not fill a deep fold, but they can help the skin around it. See HIFU vs radio frequency.
When should I leave them alone?
More often than people think. If your smile lines are only visible when you smile, or they match your age and you do not mind them, leave them. If you are in the middle of losing weight, wait until your weight is stable before deciding. And if someone suggests filling them at every visit, ask why.
I would rather tell you to wait than do a treatment you do not need. A smile line that matches your age is part of your face, and many people look better with it softened a little, or not at all, than erased.
How we approach this at Dr Tvacha
At a face assessment within the Long Game Anti-ageing Plan, I look at your face upright, smiling and lying back, to judge whether the fold, the cheek or the skin is the real issue. We decide the endgame first: what you want your face to look like in five years. Any injectable product and dose is written down and the fee is quoted before treatment.
Frequently asked questions
Are smile lines a sign of ageing?
Not only. Everyone has a nasolabial fold, and children show it when they smile. It deepens with age as cheek support and skin firmness reduce, and with weight loss. So a visible line is normal anatomy, while a deep shadow at rest is more an ageing change. Whether to treat it depends on how much it bothers you.
How long does filler in smile lines last?
It depends on the product, the amount, and how active the area is. Mayo Clinic notes hyaluronic acid fillers usually need repeating after some months, and many people need one to three sessions initially. The area around the mouth moves a lot, which can shorten how long the result lasts. I review results and plan maintenance rather than promising a fixed time.
Can smile lines be treated without fillers?
Yes, partly. Skin tightening with HIFU or radio frequency, a thread lift in selected cases, and good skincare with sunscreen and a retinoid can improve the skin around the fold. They will not fill a deep crease. For many people, softening the skin is enough. Some choose to leave the lines alone, which is perfectly reasonable.
Why do some people's smile lines look overfilled?
Usually because the fold was filled repeatedly, a little more each time, without addressing the cheek above, or because too much product was used. The mid-face then looks heavy and the smile looks unnatural. Restraint, treating the cause and reviewing in photographs help avoid this. Hyaluronic acid fillers can be dissolved if needed.
Does weight loss make smile lines worse?
It often does. When you lose weight, especially quickly, you also lose facial fat that supports the cheeks, so the folds look deeper. Reviews of GLP-1 weight loss describe deeper nasolabial folds and hollowing. I usually suggest waiting until your weight is stable before treating, so the plan matches your final face.
Written by
Dr Amit KarkhanisAesthetic Physician · MBBS, Dip. Dermatology (UK) · Reg. No. 2001/02/1124Founder of Dr Tvacha, practising in Thane since 2005. Leads the weight loss and hair programmes.
Sources
- Dermal fillers (soft tissue fillers) (US FDA)
- Wrinkles: diagnosis and treatment (Mayo Clinic)
- Aesthetic implications of GLP-1 agonists (Dermatology Times)
- Microfocused ultrasound in aesthetic medicine: an update and critical review (Journal of Cosmetic and Regenerative Medicine, 2026)
This article is for general education and does not replace a consultation. Medicines and treatments are prescribed only after a doctor's assessment. Last reviewed 25 October 2026.