Botox vs Dysport

Botox and Dysport are both TGA-approved botulinum toxin type A products, and both are clinically effective — but they are not identical, and in facial aesthetics the differences matter. Protein complex size, diffusion profile, unit dosing, and duration of effect all vary between the two formulations, and those variations have real consequences in a field where a millimetre of unwanted spread can cause ptosis, brow depression, or smile distortion.

The Same Active Molecule, Different Products

Both Botox (onabotulinumtoxinA, Allergan) and Dysport (abobotulinumtoxinA, Galderma) share the same active component: the 150 kDa botulinum neurotoxin type A molecule that cleaves SNAP-25 at the neuromuscular junction, preventing acetylcholine release and producing reversible chemodenervation.¹ The difference lies in how that active molecule is formulated and packaged.

Botox is complexed with haemagglutinin and non-haemagglutinin proteins into a larger molecular complex — approximately 900 kDa. Dysport, while also a complexed formulation, has a smaller protein complex and a different accessory protein profile.² These structural differences have downstream consequences for how the product behaves after injection.

Diffusion: The Most Clinically Significant Difference

Dysport diffuses more widely from the injection point than Botox. This is the single most clinically significant difference between the two products in facial aesthetics.

Comparative studies have consistently demonstrated greater spread of effect with Dysport relative to Botox at equivalent clinical doses.^3,4 For indications where wide coverage is desirable — such as hyperhidrosis of the axilla or treatment of large muscle groups — this broader diffusion profile can be useful. In the face, however, where muscles are small, closely packed, and anatomically interdependent, it is a significant risk factor for complications.

The glabellar complex, frontalis, and periorbital region are particularly unforgiving. The levator palpebrae superioris lies in close proximity to the corrugators; the frontalis inserts immediately above the brow; the orbicularis oculi borders the lower lid. In each of these areas, millimetres of additional spread can convert a good result into a complication.

Unit Dosing: Not Interchangeable

A common point of confusion for patients is the assumption that one unit of Dysport equals one unit of Botox. They do not. The two products use different unit assays based on their respective mouse lethality testing methods, meaning their units are not equivalent and cannot be directly substituted at a 1:1 ratio.⁵

The conversion ratio is approximately 2.5–3 Dysport units per 1 Botox unit, though this varies by anatomical site and clinical context. This has practical implications: patients who switch between products and compare unit counts are not comparing equivalent doses, and clinicians who do not account for this difference risk underdosing or overdosing.

Why I Use Botox at This Clinic

My preference for Botox is based on three converging factors: containment, familiarity, and the risk profile of my patient population.

First, the more contained diffusion profile of Botox is an advantage in facial aesthetics specifically. When treating the glabellar complex, crow's feet, frontalis, perioral lines, or masseters, I want the product to stay where I put it. The precision afforded by Botox's tighter spread profile reduces the margin for error and lowers the risk of the complications patients find most distressing — ptosis, brow heaviness, and asymmetry.

Second, my training background is hospital-based, and Botox has a deep literature base accumulated over decades across both therapeutic and cosmetic indications. The dosing parameters, anatomical protocols, and complication management data for Botox are extensive and well-characterised. This is not a limitation of Dysport — it is simply a reflection of where the evidence base is strongest and where my clinical familiarity runs deepest.

Third, my patient population frequently includes individuals with no prior treatment history, thin faces, and low frontalis reserve — characteristics that increase susceptibility to complications from diffusion-related spread. For these patients in particular, the contained profile of Botox is the more conservative and safer choice.

When Dysport May Be Preferred

It would be misleading to suggest that Botox is objectively superior in all circumstances. There are clinical scenarios where Dysport's broader diffusion profile is a genuine advantage — large-area hyperhidrosis treatment, certain therapeutic spasticity applications, or situations where a single injection point needs to cover a wider territory. In experienced hands with appropriate patient selection, Dysport produces excellent outcomes.

The decision of which product to use should reflect the clinical context, the anatomical site, the patient's history, and — critically — the injector's depth of familiarity with that product's behaviour. A clinician who knows Dysport well is better positioned to use it safely than one who uses it intermittently. The same principle applies to Botox.

Conclusion

Botox and Dysport are both effective, TGA-approved botulinum toxin type A products. Their differences — in diffusion profile, unit dosing, and protein complex — are real and clinically relevant, particularly in facial aesthetics where precision matters most. My choice of Botox reflects its more contained spread, the depth of its evidence base, and the patient population I treat. It is not a dismissal of Dysport, but a considered clinical preference grounded in the specific demands of aesthetic medicine.