Botox vs Dysport: onset, duration, diffusion, cost, and which patient fits which product

Botox and Dysport are the two most widely used botulinum toxin A products in aesthetic medicine. They share the same mechanism — blocking acetylcholine release at the neuromuscular junction to temporarily weaken targeted muscles — and the same active 150 kDa neurotoxin. But they are not interchangeable. Differences in formulation, unit-dosing convention, diffusion behavior, onset speed, and cost structure mean the right choice depends on the treatment area, the patient's priorities, and the injector's experience with each product.

This comparison covers what each FDA label says, what the clinical evidence supports, where the unit-conversion debate stands, and what patients should ask before choosing.

What each product is

Botox (onabotulinumtoxinA) is manufactured by Allergan, now part of AbbVie. It was the first botulinum toxin A product approved in the United States for cosmetic use, receiving FDA approval for glabellar lines in 2002. Beyond aesthetics, Botox holds FDA approvals for chronic migraine, hyperhidrosis, overactive bladder, upper limb spasticity, cervical dystonia, and strabismus/blepharospasm. It uses a 900 kDa complex with human serum albumin as a stabilizer and requires refrigeration at 2–8°C. Per the FDA prescribing information, the labeled dose for glabellar lines is 20 Units divided into five injections of 4 Units each.

Dysport (abobotulinumtoxinA) is manufactured by Ipsen and distributed in the U.S. by Galderma. It received FDA approval for glabellar lines in 2009, with additional approvals for cervical dystonia, upper limb spasticity in adults, and lower limb spasticity in pediatric patients. Dysport uses a smaller complex size (approximately 500–900 kDa depending on measurement method), contains human serum albumin, and also requires refrigeration. Per the FDA prescribing information, the labeled dose for glabellar lines is 50 Units divided into five injections of 10 Units each.

The active toxin molecule is the same 150 kDa botulinum toxin type A in both products. The behavioral differences arise from the complexing proteins, excipient ratios, and the proprietary unit assays — which are product-specific and not interchangeable.

The unit conversion problem

This is the most clinically important and most commonly misunderstood distinction.

Botox Units and Dysport Units measure different things. Each product's potency is determined by its own proprietary mouse bioassay. A "unit" of Botox is not the same as a "unit" of Dysport. Both FDA labels state explicitly that their units are not interchangeable with any other botulinum toxin product.

The most commonly cited conversion ratio is approximately 1:2.5 to 1:3 (Botox:Dysport). This means 20 Units of Botox for the glabellar region is roughly equivalent to 50–60 Units of Dysport for the same area.

However, the conversion ratio has been debated in the literature for over two decades:

A 2016 review in Toxins analyzing conversion studies concluded that ratios of 1:4 or higher may lead to excessive Dysport dosing with more adverse events, while 1:3 or lower tends toward clinical equivalence.

In practice: most experienced injectors use a Botox-to-Dysport conversion of approximately 1:2.5 to 1:3 and adjust based on individual patient response. Patients should not do their own conversion arithmetic.

Onset: Dysport is faster

Dysport's smaller complex size is associated with faster tissue diffusion, which translates to a slightly faster onset of effect.

Dysport: Many patients begin to notice softening of treated lines within 2–3 days after injection. Peak effect typically occurs at 7–14 days.

Botox: Initial onset is typically reported at 3–5 days for most patients, with peak effect at 7–14 days. Some patients, particularly those new to neuromodulators, may not notice visible changes until closer to the 10–14 day mark.

The difference in initial onset is measured in days, not weeks. For most patients it is not clinically significant. However, for patients treating for a specific event (a wedding, a photoshoot) with a tight timeline, Dysport's earlier onset may be advantageous.

Duration: essentially equivalent

Both products have a labeled cosmetic duration of approximately 3–4 months for glabellar lines. In clinical practice:

• Most patients return for retreatment at 3–4 month intervals with either product.
• Some patients report slightly shorter duration with Dysport compared to Botox, but this is inconsistent across studies and may reflect dosing differences rather than true product-level variation.
• Individual metabolism, muscle mass, treatment area, and injection technique affect duration more than the choice between these two products.

Unlike Daxxify — which has demonstrated 6-month duration in clinical trials — neither Botox nor Dysport makes a claim beyond 4 months. Patients expecting longer duration from either product will need to adjust expectations or consider Daxxify instead (see our Daxxify vs Botox comparison).

Diffusion: Dysport spreads more

Diffusion — how far the toxin travels from the injection site — is where the two products diverge most noticeably in practice.

Dysport has a documented tendency toward wider diffusion from each injection point. This is a double-edged property:

• Advantage: Wider spread can cover larger treatment areas with fewer injection points. A full forehead treatment may require fewer sticks with Dysport than with Botox. Some patients and providers report a softer, more natural-feeling result, particularly in broad areas.
• Disadvantage: Wider spread increases the risk of unintended muscle involvement. The most common concern is eyelid ptosis (drooping) when treating the forehead or glabellar region, because the toxin can diffuse into the levator palpebrae muscle. This risk is technique-dependent and mitigated by experienced injectors.

Botox tends to remain more localized at the injection site, offering more precision. This is advantageous for:

• Small, high-stakes areas (brow shaping, lip flips)
• Areas where unintended spread would be problematic (masseter treatment, periorbital region)
• Patients concerned about ptosis or asymmetry

The diffusion difference is not absolute. Injection technique, dilution volume, and injection depth all influence spread, and an experienced injector can compensate for either product's diffusion characteristics.

FDA-approved indications

Botox has a substantially broader FDA indication base, particularly in the cosmetic space. Botox is the only botulinum toxin A product FDA-approved for crow's feet and forehead lines. When Dysport is used for these areas, it is off-label — which is legal, common, and clinically routine, but patients should be informed.

For therapeutic uses beyond aesthetics (migraine, hyperhidrosis, bladder), Botox is often the only option with regulatory backing. Dysport's therapeutic approvals are narrower.

Cost comparison

Neither product is generic, and pricing varies significantly by geography, provider credentials, and practice type. The following ranges reflect 2026 U.S. averages from multiple provider databases.

The per-unit price difference is misleading without the conversion context. Because Dysport uses more units per treatment area (approximately 2.5–3× more), the total per-session cost ends up similar. At the national average, a glabellar treatment costs roughly the same with either product.

Metro-level pricing (2026, median at established practices):

Botox also has the Allē loyalty program (formerly Brilliant Distinctions by Allergan), which returns approximately $20 in points per treatment. Over four treatments per year, that is roughly $80 back — a modest but real rebate that Dysport's Aspire Rewards program matches at similar levels.

Side effect profiles

Side effect profiles are broadly similar, as expected for products sharing the same active molecule and mechanism. Per the FDA labels:

Botox (glabellar lines, clinical trial data):

• Headache: reported in clinical trials
• Eyelid ptosis: reported
• Facial pain: reported
• Injection site reactions (bruising, redness, pain): common

Dysport (glabellar lines, clinical trial data):

• Headache: commonly reported
• Eyelid ptosis: reported
• Nasopharyngitis: reported
• Injection site reactions: common

Both carry the class-wide FDA boxed warning for potential distant spread of toxin effects, including dysphagia, dysphonia, and breathing difficulties. These events are rare at cosmetic doses but can be life-threatening. The boxed warning applies to all botulinum toxin products regardless of manufacturer.

Dysport's wider diffusion profile may theoretically increase the risk of unintended effects in adjacent muscles (particularly ptosis), but this has not been consistently demonstrated in controlled trials and is highly technique-dependent.

Which product for which facial area

The diffusion difference between Botox and Dysport makes each product better suited to specific treatment areas:

This area-by-area logic is consistent across experienced injectors, but it is not absolute. A highly skilled injector can use either product in any area by adjusting injection depth, dilution volume, and placement.

Who is each product best for?

Botox may be a better fit for patients who:

• Want the most extensively studied botulinum toxin A product, with the broadest FDA-approved indication base
• Are treating areas where precision matters more than speed (brow shaping, lip flip, masseter reduction)
• Have therapeutic needs beyond aesthetics (chronic migraine, hyperhidrosis) and want a single product for all injections
• Are concerned about wider diffusion and potential ptosis
• Want FDA-approved treatment for crow's feet or forehead lines, not off-label use

Dysport may be a better fit for patients who:

• Want the fastest possible onset (2–3 days vs 3–5 days)
• Are treating large areas (full forehead) where wider diffusion is efficient and fewer injection points are an advantage
• Prefer a softer, more spread effect rather than a localized one
• Are new to neuromodulators and want a lower per-session price point (though total cost is similar)
• Have used Botox before and felt results were too localized or created a "heavy" feeling

Neither product is right for patients who:

• Have known hypersensitivity to botulinum toxin type A or any product component (lactose in Dysport, albumin in both)
• Have an active infection at the planned injection site
• Are pregnant or breastfeeding (neither product has adequate data in these populations)
• Have a pre-existing neuromuscular disorder (myasthenia gravis, Lambert-Eaton syndrome, ALS) without specialist supervision
• Are taking aminoglycoside antibiotics or other agents that interfere with neuromuscular transmission

What to ask before choosing

1. Which product does the injector use most often? Injector experience outweighs product choice for most outcomes. A provider who has performed 1,000 Botox sessions will produce better results with Botox than with a product they have used 50 times — and vice versa.

2. Is the price per unit or per area? Per-area pricing obscures how much product is actually injected. Per-unit pricing is more transparent but requires trust in the stated count. Ask specifically.

3. What happens if I do not like the result? Both products last approximately the same time. If you are unhappy, you wait 3–4 months for either product to wear off. There is no "antidote" for neuromodulator results — only time.

4. Are you using this on-label or off-label? If your provider is using Dysport for crow's feet, forehead lines, masseter reduction, or any area beyond the glabellar lines, that is off-label. It is standard practice, but you should be told.

5. What is your plan for ptosis? Eyelid ptosis is the most common meaningful adverse event for both products. An experienced injector has a protocol — typically apraclonidine (Iopidine) eye drops, which stimulate Müller's muscle to temporarily lift the eyelid.

Sources

• Botox (onabotulinumtoxinA) prescribing information, FDA. accessdata.fda.gov/drugsatfda_docs/label/2024/103000s5392lbl.pdf
• Dysport (abobotulinumtoxinA) prescribing information, FDA. accessdata.fda.gov/drugsatfda_docs/label/2023/125274s125lbl.pdf
• Scaglione F. "Conversion Ratio between Botox®, Dysport®, and Xeomin® in Clinical Practice." Toxins (2016) 8(3):65. pmc.ncbi.nlm.nih.gov/articles/PMC4815744/
• Ranoux D et al. "Respective potencies of Botox and Dysport: a double-blind, randomised, crossover study in cervical dystonia." J Neurol Neurosurg Psychiatry (2002) 72:459–462.
• Yun JY et al. "Dysport and Botox at a ratio of 2.5:1 units in cervical dystonia: a double-blind, randomized study." Toxins (2023).
• Wohlfarth K et al. "Biological activity of two botulinum toxin type A complexes (Dysport and Botox) in volunteers: a double-blind, randomized, dose-ranging study." J Neurol (2008) 255:1932–1939.
• American Society of Plastic Surgeons, 2024 Procedural Statistics. plasticsurgery.org/documents/news/statistics/2024/plastic-surgery-statistics-report-2024.pdf
• FDA Boxed Warning for Botulinum Toxin Products. fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/fda-drug-safety-communication-fda-requires-boxed-warning-and-risk-evaluation-and-mitigation