DAO Botox: Understanding Your Options for a Natural-Looking Smile

“DAO Botox” usually refers to botulinum toxin treatment of the depressor anguli oris, a muscle involved in pulling the corners of the mouth downward. The aim is to reduce that pull in selected people. It does not mean every downturned mouth needs an injection, or that treatment can guarantee a particular smile.

This guide explains the term, the limits of the evidence and questions to discuss with a qualified clinician. The information here is general education; a qualified clinician needs to assess your concerns, health history and exact treatment options.

What does DAO Botox mean?

The DAO is one part of the moving lower face. It works near muscles that control the lower lip, so the concern is more specific than simply “lifting the face.” An anatomical study of 45 cadavers found partial overlap between the DAO and the depressor labii inferioris, a lower-lip muscle. That relationship helps explain why preserving movement matters.

Botox Cosmetic is the brand name for onabotulinumtoxinA. DAO treatment is off-label: the current US label does not list DAO treatment or downturned mouth corners among its approved indications. Approval for another facial or neck area does not establish approval for the DAO. Botox Cosmetic prescribing information, section 1.

Ask which exact product is proposed. Other botulinum toxin brands are not interchangeable with Botox Cosmetic, and their potency units cannot be compared or converted. Prescribing information, section 5.1.

Start with the mouth-corner concern

Describe what you notice before choosing a procedure: a downward pull during expression, a resting shape you have always had, a fold beside the mouth or a change in lower-face contour. Bring examples of your usual expression and explain which change concerns you.

Ask the clinician to assess whether DAO movement is relevant and what else needs consideration. A photograph or a social-media before-and-after cannot determine that for you. Our chin and jawline anatomy guide introduces the broader lower-face discussion; this article focuses on mouth-corner movement.

Keep nearby treatments distinct. A lip flip addresses a different upper-lip question. Masseter treatment concerns a chewing muscle. Neither is the same as assessing the DAO, and this guide does not establish a jowl-lifting or whole-face treatment plan.

What does the research show?

A small randomized, placebo-controlled study enrolled 20 adults aged 18–65: ten received onabotulinumtoxinA and ten received saline. The treated group showed improvement in DAO contraction scores at weeks four and twelve compared with baseline; the placebo group did not show a significant change between visits. The study also assessed appearance using a global improvement scale. 2023 DAO clinical trial.

That is relevant evidence for a possible benefit, with clear limits. Ten treated participants and a particular study technique do not establish that everyone will respond, that complications cannot occur or that another product will give the same result. The study does not justify a guaranteed amount of lift.

Be careful with timing claims. Improvement at a twelve-week study visit does not promise a twelve-week result for every person or tell you exactly when your own result would start or end. Ask how and when the clinician would assess your response instead of borrowing a forehead-treatment timeline. The trial report is the basis for these study observations.

Protecting smile and lower-lip movement

A useful discussion includes how your mouth moves while smiling, speaking and using the lower lip. The DAO/DLI overlap study explains how unintended involvement of a neighboring muscle can change facial animation. Anatomy research identifies a concern; it does not supply a personal complication rate. DAO and lower-lip anatomy study.

Discuss unwanted smile asymmetry or lower-lip weakness explicitly, including whom to contact and how a problem would be evaluated. A “natural-looking” goal should include comfortable movement and a result you understand, rather than only a still photograph.

Botox Cosmetic is contraindicated with injection-site infection or relevant toxin/ingredient allergy. Disclose neuromuscular conditions, swallowing or breathing difficulties, medicines, previous toxin treatments, pregnancy plans and breastfeeding. Prescribing information and Medication Guide.

Its boxed warning describes toxin effects spreading beyond the injection area. Seek immediate medical attention for difficulty swallowing, speaking or breathing after treatment. These can be serious. Boxed warning and Medication Guide.

Questions to ask before deciding

1. What is causing the mouth-corner appearance I notice, and how much is related to DAO movement?
2. Which exact product are you proposing, and what does its off-label use mean for this plan?
3. What change is realistic, and what is unlikely to change?
4. How will we document my usual smile, lower-lip movement and any existing asymmetry?
5. What risks apply to my health history, and what is the plan if movement changes unexpectedly?
6. When would you assess the result, and what does follow-up include?
7. What is the total cost, and what are the alternatives, including choosing no treatment?

Take these questions to a qualified clinician before deciding. You can also browse Calista’s Neurotoxin Guides for related education. Confirm a clinic’s exact service and product availability directly before arranging a treatment visit.