Often I am asked if Botox and Dysport are the same. Or, more commonly, a patient will prefer one over the other. The simple answer is that the active molecule is essentially the same and the protein that surrounds it is different.
For the most part, they work the same. Unfortunately, the units are different (how they are measured), so one unit of Botox is not the same as one unit of Dysport. In my opinion, the manufacturer of Dysport overstated their conversion–meaning that the recommended conversion was not strong enough. Therefore, I have found that one must use more than the original recommended amount.
In general, I often get better “deals” from one company at a given time, which I personally pass down to the patient. The two products do behave a little differently (how they spread), but for the most part I think the results are extremely close.