Which line is which, and what causes it?
Three things get called lines around the mouth, and they are different. The first is the fine vertical line on the upper lip, called a lipstick line or smoker's line, where colour can bleed into the crease. The second is a change in the lip itself: thinner, flatter, with less visible red. The third is the fold running down from the corner of the mouth, the marionette line.
A 2021 review of perioral ageing lists the contributors: sun exposure, bone resorption, repeated contraction of the muscles around the mouth, gravity, changes in the skin and unhealthy habits. The signs it describes include fine lip wrinkling, a flatter upper lip, downturned corners, marionette lines and reduced visible lip. Several causes can sit together, which is why the same remedy does not suit every mouth.
Smoking has data behind it. A cross-sectional study of 143 people aged 21 to 91 built a model of perioral wrinkle severity that included age, gender and years of smoking. It was a small, mostly Caucasian sample and it shows association, so it cannot give a figure for any one person.
What can low-dose toxin do for vertical lip lines?
Vertical lines deepen because the ring of muscle around the mouth contracts every time lips purse. Botulinum toxin (anti-wrinkle injections, often called Botox) relaxes that muscle a little. In a 2012 dose-ranging trial, 60 women received either 7.5 or 12.0 units across four sites. Lines were reduced through week 16 at the lower dose and week 20 at the higher, and responder rates at week 12 were 77% and 36%. The authors concluded that the lower dose looked adequate for up to 16 weeks, and that adverse events were mostly mild to moderate and rose with dose.
The risk is specific to this area. Weakening the muscle that closes the lips can cause trouble pronouncing certain words, drinking through a straw, spitting, whistling or eating with a spoon, according to a 2025 review, which adds that it may not suit people who sing or speak professionally. The effect is temporary, but it lasts as long as the treatment does. A weak or uneven smile is the related concern when toxin spreads beyond the target, and the side effects page sets out what to tell a doctor early.
Can hyaluronic acid filler soften lip lines and add lip volume?
Soft hyaluronic acid filler (a gel that holds water) is the option with randomised evidence for the lines themselves. In a 2015 rater-blinded trial of 136 people aged 35 or older with moderate to severe perioral lines, two different hyaluronic acid fillers were compared. At month 6, 87% in one group and 72% in the other had improved by at least one point on a four-point scale, and no unexpected adverse events occurred. The trial compared products with each other and does not make either one a recommendation.
Filler also adds volume to a lip that has thinned. The trade-off is that too much gel or the wrong depth gives a heavy, unnatural mouth. Swelling, bruising and the rarer risks are covered in the lip filler article, including what dissolving filler involves.
What about marionette lines?
These behave differently. A marionette line is the edge of a shadow formed where support beneath the skin has softened or descended, and the downturned corner pulls it further. Easing the surface line alone changes little. The longer explanation of why folds are a support problem is in which wrinkle treatment fits which line.
Where the problem is lost volume across the lower face, filler placed for support is the usual conversation, sometimes with toxin to the muscle that pulls the corner down. Both carry the lower-face cautions above, and a doctor may reasonably decide that nothing should be done.
What do skin treatments, sun protection and stopping smoking add?
Lines that are partly skin quality respond to treatments that work on the skin rather than the muscle. The 2021 review places mild chemical peels in the range of options, which runs from muscle-relaxing injections to surgery. Other resurfacing and microneedling techniques are used for these lines too, and radiofrequency microneedling is not offered here, for the reasons set out in why this clinic does not offer RF microneedling. No outcome figures for those techniques were verified for this article, so none are quoted. The chemical peel article explains depths and who they suit.
Sun protection and stopping smoking do not remove lines, but they remove two of the contributors named above. Daily protection that covers UVA is explained in the sunscreen article. Prescription retinoids are a common skin-care step, but no perioral study was read for this article, so their effect on lip lines is not claimed.
What can none of these do?
None stops ageing or reverses bone loss. None makes a mouth that moves look the way it does in a photograph, and every one carries a cost: toxin the function risk, filler the swelling and volume risk, skin treatments downtime. Choosing between them starts with which line it is, then with whether any treatment is better than none.
