How Many Units of Dysport for Crow's Feet? How Providers Plan Treatment

There is no FDA-labeled number of Dysport units for crow's feet: Dysport's U.S. cosmetic approval covers the frown lines between the eyebrows, so using it for the lines at the outer corners of the eyes is off-label, and any dose is a clinical judgment made after an in-person examination. This guide explains what that means, why unit counts you see online can mislead, and what a careful plan for crow's feet takes into account.

Is Dysport approved for crow's feet?

Dysport (abobotulinumtoxinA) is a prescription botulinum toxin. Its FDA prescribing information lists one cosmetic use: the temporary improvement in the appearance of moderate to severe glabellar lines, the vertical frown lines between the eyebrows, in adults younger than 65. For that use, the label gives specific dosage and injection instructions. The label does not include crow's feet, which clinicians call lateral canthal lines.

The FDA explains that once a drug is approved, health care providers generally may prescribe it for an unapproved use when they judge it medically appropriate for a patient. That is what "off-label" means. It also means the FDA has not reviewed Dysport's benefits, risks or dosing specifically for crow's feet, so there is no labeled dose to quote.

A different botulinum toxin product, Botox Cosmetic (onabotulinumtoxinA), does have FDA approval and a labeled dose for moderate to severe lateral canthal lines in adults. That approval belongs to that product only and does not transfer to Dysport.

Why can't a Botox crow's feet dose be converted into Dysport units?

Each botulinum toxin product measures its units with its own test. The Dysport label states that its units are specific to its preparation and assay method, and that they cannot be compared to or converted into units of any other botulinum toxin product. MedlinePlus makes the same point for patients: one brand or type of botulinum toxin cannot be substituted for another.

So a forum post that names a number for "Dysport in crow's feet," or a chart that multiplies a Botox dose by a fixed ratio, is not a reliable guide for your face. A higher unit number on a Dysport plan does not mean more treatment than a lower number with another brand, and the reverse is also true.

Are your crow's feet dynamic or static wrinkles, and why does it matter?

Crow's feet are the fine lines that form at the outer corners of the eyes. The American Society for Dermatologic Surgery (ASDS) says they are primarily caused by sun exposure, and that smoking can contribute. ASDS describes two main types:

• Dynamic wrinkles are produced by the underlying facial muscles. Smiling, squinting and frowning activate them.
• Static wrinkles are present all the time, even during sleep. They build up over years of squinting, frowning and sun damage.

The difference shapes the plan. ASDS explains that neuromodulators such as Botox, Dysport and Xeomin relax the underlying muscle, and that they are usually the preferred option when crow's feet are dynamic. Lines that stay visible when your face is relaxed may not respond fully to a muscle relaxer alone. ASDS also lists chemical peels and laser resurfacing as options for crow's feet. Ask which approach fits your skin concern and what risks it carries. Ask your provider which type your lines are before you talk about units.

What does a provider look at when planning crow's feet treatment?

Crow's feet form where the muscle that circles the eye contracts when you smile or squint. A planning visit is likely to cover:

• Your treatment goals. ASDS describes the visit before treatment as the time to discuss expectations, potential risks and outcomes. Say what you hope to soften and what you want to keep, such as natural movement when you smile.
• How the muscle moves. How far the lines fan out, and whether they extend toward the cheek or lower eyelid, affects where and how many injection points are considered.
• Symmetry. Many people squint or smile more on one side. Differences that already exist should be noted before treatment.
• Eyelids, dry eyes and past procedures. For its approved frown-line use, the Dysport label advises caution in people with surgically altered facial anatomy, marked facial asymmetry or drooping eyelids, and notes that dry eye has been reported with that use.
• Other treatment areas. If frown lines or other facial wrinkles are treated at the same visit, each area adds to the total dose for that session.

Because this is off-label use, your clinician should be able to explain how they choose the dose and injection sites for you, why they recommend Dysport rather than a product approved for this area, and what they would do if the result is uneven. ASDS notes that the effect of neuromodulators on crow's feet typically lasts about three months, so it also helps to talk about whether and how often you would want repeat treatment.

Who may need extra caution?

According to its label, Dysport should not be used in people with a known allergy to any botulinum toxin product, to cow's milk protein, or to any ingredient in the product, or when there is an infection at the planned injection site. The label calls for close monitoring of people with neuromuscular disorders such as myasthenia gravis, and notes that people who already have swallowing or breathing problems may be more susceptible to those complications.

MedlinePlus also asks patients to tell their doctor about any history of eye surgery. The label reports no adequate studies of Dysport in pregnant women, so tell your provider if you are pregnant, planning a pregnancy or breastfeeding, and share a full list of your medicines and supplements.

What side effects should you report to your provider?

In the frown-line trials described in the Dysport label, reported reactions included injection site pain, eyelid swelling, a drooping eyelid, nausea, and nose and sinus symptoms. For crow's feet treatment with neuromodulators in general, ASDS lists soreness, mild bruising, temporary weakness of surrounding muscles and headache. ASDS also advises not rubbing treated areas, because that could move the medicine to another area.

Call your provider about a drooping eyelid or brow, uneven results, bruising or swelling that is not settling, or eyes that feel dry, irritated or sensitive to light. The label asks patients to report dry-eye symptoms so they can be assessed.

When do symptoms need emergency care?

All botulinum toxin products, including Dysport, carry a boxed warning that their effects may spread beyond the injection area. The Dysport Medication Guide tells patients to get medical help right away for problems swallowing, speaking or breathing, or for signs that the effect has spread, such as weakness all over the body, double or blurred vision, drooping eyelids along with other symptoms, a hoarse voice, slurred speech or loss of bladder control. These problems can appear hours to weeks after an injection. Call 911 for any trouble breathing or swallowing.

Questions to ask about a crow's feet plan

• Is the product you recommend approved by the FDA for crow's feet? If not, why do you prefer it?
• How will you choose my dose and injection points, and will you record them for future visits?
• Are my lines mostly from movement, mostly present at rest, or both? Would another treatment help more?
• Do my eyelids, dry eyes, past surgery or medicines change your plan?
• Which side effects should I expect, and which should prompt a call or emergency care?
• What happens if the result is uneven?

Prepare with our botulinum toxin consultation safety questions, learn about facial aesthetics at Anew Laser MD, or use the contact page to ask whether Dysport is offered at your location. Individual results vary.

Independent sources

• FDA: Dysport (abobotulinumtoxinA) prescribing information and Medication Guide, revised 09/2023
• FDA: Botox Cosmetic (onabotulinumtoxinA) prescribing information, 2024
• FDA: Understanding unapproved use of approved drugs "off label"
• MedlinePlus: AbobotulinumtoxinA injection
• American Society for Dermatologic Surgery: Neuromodulators for crow's feet
• American Society for Dermatologic Surgery: Crow's feet, dynamic and static lines