There are several therapeutic products based on botulinum toxin, with two units of measure.

The majority of products are based on Botulinum toxin A.



Abobotulinum toxin (ababotA, ABO)

Obobotulinum toxin (onabotA, ONA)

Product Names

Azzalure, Dysport

Botox, Vistabel

Units of Activity




Both agents are different although they both involve Botulinum toxin A:

(1) methods of neurotoxin isolation

(2) methods of purification

(3) differences in neurotoxin-associated proteins (NAPS)

(4) differences in molecular weight complexes

(5) FDA approval for use


There is no direct conversion between the 2 toxins since they show a number of differences. Final dosing often depends on titrating effects after starting with an initial dose.


Determining the initial dose: 1 Botox unit for each 2.5 Speywood units, or 1 Speywood unit for each 0.4 Botox units.


Other botulinum toxins:

(1) Xeomin (toxin type A): dosing is equivalent to Botox

(2) Neurobloc (Botulinum toxin type B)

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