Dysport vs Botox Units: Is There a Safe Conversion Ratio?

Dysport units and Botox units are not interchangeable. Dysport (abobotulinumtoxinA, Ipsen/Galderma) and Botox (onabotulinumtoxinA, Allergan/AbbVie) are each measured with their own manufacturer-specific assay, so a "Dysport to Botox conversion" is only a clinical estimate. Published estimates cluster around 2.5 to 3 Dysport units per Botox unit, but both labels forbid direct conversion.

Key Takeaways

• Both the Dysport and Botox Cosmetic U.S. labels state that their units cannot be compared to or converted into units of any other botulinum toxin product.
• Literature ratios vary widely; the best-structured review, limited to movement disorders, supports roughly 1:2.5 to 1:3 (Botox:Dysport) and discourages ratios above 1:3.
• Labeled glabellar-line doses differ: 20 Units for Botox Cosmetic and 50 Units for Dysport, each with its own injection scheme.
• Storage for unopened vials is the same on both labels: refrigerated at 2°C to 8°C.
• For distributors and clinics, the practical safeguards are authentic sourcing, cold-chain integrity and product-specific training.

Why Aren't Dysport and Botox Units Interchangeable?

Units are defined by each manufacturer's own potency assay and reference material, so a unit of one product does not represent the same biological activity as a unit of another.

The Dysport label states that its potency units "are not interchangeable with other preparations of botulinum toxin products" and that its units "cannot be compared to or converted into units of any other botulinum toxin products assessed with any other specific assay method." The Botox Cosmetic label uses parallel wording: it "is not equivalent to other preparations of botulinum toxin products." A 2010 review of glabellar-line treatment made the same point, noting that both products are measured in units of biologic activity but "the units are not transposable due to differences in assays used to determine the units."

In practice, this means the units on the vial are meaningful only inside that brand's own dosing framework: its labeled doses, dilution table and injection sites.

What Conversion Ratios Appear in the Literature?

Published ratios range from about 1:2.5 to 1:4 (Botox:Dysport) in controlled trials, and a broader 2010 review cited figures between 2:1 and 11:1 across the literature, which illustrates how unsettled the question is.

A 2016 systematic review of onabotulinumtoxinA and abobotulinumtoxinA dose conversion (Dashtipour et al., Movement Disorders Clinical Practice) searched PubMed, Cochrane and EMBASE and included four randomized studies, all in movement disorders. One study used 1:2.5, two used 1:3 and two used 1:4. The authors concluded that 1:2.5 to 1:3 gave comparable efficacy and safety, and that 1:4 "appears to yield an undesirable trade-off" with more adverse events. Importantly, the authors stress that results from movement disorders should not be assumed to transfer to other indications, and the review was partly funded by Ipsen.

The 2010 glabellar-line review reached a similar cautious view: randomized trials favored 3:1 over 4:1, but the authors warned that "the studies do not prove that a 3:1 dose ratio is equivalent clinically."

How Do the Labeled Glabellar Doses Compare?

The labeled glabellar-line dose is 20 Units for Botox Cosmetic and 50 Units for Dysport, but these are separate dosing systems, not a conversion rule.

Note that the Dysport label provides several dilution options with different concentrations per 0.1 mL, so the injected volume per site depends on the dilution chosen. A unit-for-unit swap or a volume-for-volume swap between brands can therefore produce a very different effective dose.

Do Dysport and Botox Differ in Spread, Onset and Duration?

The evidence is not conclusive. Diffusion appears to depend heavily on concentration, volume and technique rather than on the brand alone.

The 2010 review found that several studies reported no significant diffusion difference between Botox and Dysport, and that "the higher the concentration and the greater the volume, the greater the diffusion potential." Onset for botulinum toxin type A in glabellar lines was described generally as within three days to two weeks, with effects commonly lasting three to six months; the review did not give product-specific figures for these. The same review noted one comparison (Lowe et al.) reporting longer efficacy in the Botox arm at week 12. Because trial designs, doses and endpoints differ, treat head-to-head claims cautiously and rely on the product labeling and your own clinical experience.

What Should Clinics and Distributors Check When Handling Both Toxins?

Treat each brand as its own system: separate protocols, verified authentic product, and an unbroken cold chain from supplier to clinic.

• Brand-specific protocols. Keep dilution charts and injection maps per product; do not reuse one brand's chart for another.
• Authenticity. Verify packaging, lot and supply source before use. See our checklist for verifying authentic botulinum toxin. The Dysport carton carries a hologram, according to its label.
• Cold chain. Both labels require 2°C to 8°C for unopened vials. Request temperature documentation for shipments.
• Handling detail. For a worked example of a product-specific handling guide, see our Nabota dosage, dilution and storage guide, and for another Korean toxin profile see the Botulax 100U guide.
• Documentation. Record brand, lot, units and dilution at every session so any later brand change can be reviewed.

HolyPath lists Dysport 500 Units and Allergan Botox 100 Units, alongside Korean options such as Nabota 100 Units and Botulax 100 Units. Regulatory status differs by country, so confirm what is permitted in your jurisdiction before ordering.

Frequently Asked Questions

Is 1 unit of Botox equal to 1 unit of Dysport?

No. Botox Cosmetic and Dysport are each measured in units tied to a manufacturer-specific assay, and both U.S. labels state that their units cannot be compared to or converted into units of any other botulinum toxin product. Dose each product according to its own labeling and clinical judgment.

What is the Dysport to Botox conversion ratio?

There is no official ratio. Published estimates range widely; a systematic review of movement-disorder trials found 1:2.5 to 1:3 (Botox:Dysport) comparable, and discouraged ratios above 1:3. Because the manufacturers' labels prohibit conversion, any ratio is a clinical estimate, not a labeled equivalence.

Do Dysport and Botox spread differently?

Evidence is mixed. A 2010 review of glabellar-line studies reported that several studies found no significant difference in diffusion between the two, and that spread appears to depend more on concentration and injected volume than on complex size. Technique, dilution and placement remain the practitioner's responsibility.

How should unopened Botox and Dysport vials be stored?

Both U.S. labels direct that unopened vials be stored refrigerated at 2°C to 8°C (36°F to 46°F). The Dysport label adds that vials should be protected from light. Reconstituted product is labeled for refrigerated storage and use within 24 hours.

Can a clinic switch patients between toxin brands?

Clinics do switch, but each brand should be treated as a separate product with its own dose, dilution and onset profile. Practitioners typically document the product and lot used, start from the labeled dose of the new brand, and review the response at follow-up before adjusting.

Conclusion

There is no validated formula for converting Dysport to Botox. The sound approach is to dose each toxin from its own label, start conservatively when switching brands, and review the outcome at follow-up. Clinics and distributors comparing toxin portfolios can send a wholesale inquiry to HolyPath for product availability and documentation.

References

• DailyMed: DYSPORT (abobotulinumtoxinA) prescribing information, Galderma, revised 09/2023
• DailyMed: BOTOX Cosmetic (onabotulinumtoxinA) prescribing information, Allergan/AbbVie
• Dashtipour K, et al. OnabotulinumtoxinA and AbobotulinumtoxinA Dose Conversion: A Systematic Literature Review. Mov Disord Clin Pract, 2016
• Tremaine AM, McCullough JL. Botulinum toxin type A for the management of glabellar rhytids. Clin Cosmet Investig Dermatol, 2010;3:15-23

This article is for informational purposes for licensed medical professionals and distributors. It is not medical advice. Treatments should be performed only by qualified practitioners in accordance with local regulations.