DAO (Depressor Anguli Oris) Botox: How I explain it to patients
DAO Botox safely relaxes the small muscle that pulls your mouth corners down, subtly lifting them for a less “sad” or tired look with low risk when placed precisely. 1, 2
What it does
- The DAO pulls the mouth corners downward; tiny doses of botulinum toxin A weaken it, allowing elevators to lift the corner slightly (a “mouth-corner lift”) and soften marionette-line tension. Expect a natural, not “frozen,” change. 1
What you’ll notice and when
- Onset: 3–7 days; peak around 2 weeks; lasts about 3–4 months. Small lift in the corner of the mouth and a less downturned, less displeased resting expression. 1
- Evidence note: Lower (more inferior) DAO injection points lift more effectively than higher points, and adding select platysma points can further improve corner position in some cases, with minimal added risk. 3
How we inject (precise and safe)
- One intramuscular point per side, just lateral to the marionette line/labiomandibular fold, kept within a “safe zone” to avoid the depressor labii inferioris (which would drop the lower lip if hit). Typical total dose ≈ 5–6 units split across both sides. 1
- Ultrasound guidance improves accuracy because DAO position varies among people; it helps avoid neighboring muscles and improves predictability. I recommend it. 4, 2
Benefits for morbidity, mortality, and quality of life
- Primary benefit is quality of life: softens a displeased look that can affect social interactions and self-perception; trials show objective mouth-corner elevation and higher satisfaction when optimal sites (lower DAO, ± platysma) are used. 3
- No mortality or major morbidity impact in healthy cosmetic patients when performed correctly; safety hinges on precise placement. 1
Risks and how we minimize them
- Most common: temporary weakness where treated; potential asymmetry, smile changes, or mild speech/chew changes if toxin spreads.
- Key pitfall: Hitting the depressor labii inferioris can cause lower-lip inversion/asymmetry. We avoid this by staying lateral to the marionette line, using low doses, and favoring lower DAO targeting; ultrasound further reduces this risk. 1, 4, 2
- Severe botulism-like effects are extraordinarily rare with cosmetic dosing; systemic toxicity guidance exists for iatrogenic botulism, but this pertains to high-dose therapeutic/accidental exposures, not standard cosmetic DAO treatment. 5
What to expect on the day
- Few tiny injections; minimal discomfort; no anesthesia needed. Small bumps or bruises can occur and resolve quickly. Avoid rubbing the area, strenuous exercise, or face-down massage for 4–6 hours.
When we might add the neck (platysma)
- If the corner downturn is partly from neck bands/jawline pull, adding small platysma doses can enhance the lift and satisfaction without notable extra side effects. 3
Setting expectations
- Lift is subtle but noticeable in photos and at rest. Some patients perceive the change as modest; retreatment every 3–4 months maintains results. 6
Why precision matters most