Botox vs Dysport

My long answer to the  “Botox vs Dysport” debate is the substance of this blog post.  It is not a discussion I love having, though you would not know that based on the frequency of how often I have it.  Botox and Dysport are both formulations of botulinum toxin type A.  For reference, the bacteria Clostridium botulinum makes eight different types of toxins (A, B, C1, C2, D, E, F, and G), and all of the FDA approved injectable formulations are based on the same type (botulinum toxin A).  The molecule naturally occurs as a protein-toxin complex, with a large carrier molecule and comparably smaller toxin molecule.
 

What is Botox?

Botox (onabotulinumtoxin A) is made by Allergan, and is supplied as a lyophilized (dried) form.  A vial of Botox contains a small amount of human serum albumin (a protein found in humans and other animals as well), sodium chloride (salt), and the neurotoxin complex, a protein-toxin complex with a mass of 900kD.  Botox is typically available in 100 unit and 50 unit vials.  The vials have to be refrigerated and stay that way until they are reconstituted with normal saline, and then injected.
 

What is Dysport?

Dysport (abobotulinumtoxin A) is made by Galderma, and is also supplied as a lyophilized powder.  A vial contains human serum albumin, lactose, and the neurotoxin complex with some of the carrier molecule cleaved, or cut, from the protein-toxin complex with a mass of 500-900kD. Why is there a range of values?  Well, the process of cutting the carrier protein involves using proteases, which are proteins that cut other proteins, and they leave a range of carrier molecules rather than a single size.  Does this matter?  It is hard to say.  Usually, a single vial of Dysport has 300 units, which in my practice, is equal to 100 units of Botox or Xeomin.  As opposed to Botox, Dysport does not have to be refrigerated (though I do anyway, because I figure it can’t hurt, and I just sleep better at night doing this).  I do not think refrigeration should be a large factor in the “Botox vs Dysport” debate.
 

Botox vs Dysport: Different Units

When I say they are “equal”, I mean that they produce an equivalent effect once injected.  To make the bookkeeping simpler, I refer to 3 units of Dysport as “1 unit”, so that all 3 of my injectable neuromodulators, Botox, Dysport, and Xeomin, have interchangeable units.  This does make price comparing a little confusing, as my Dysport appears to be 3 times as expensive as other people in town.  
 
I see this difference as semantics, and would rather have the simplicity of interchanging units, and also pass this simplicity on to my patients, rather than explaining, “last time you got 10 units of Botox, and since you wanted to try Dysport this time, it will be 30 units”.  Trust me, that is the beginning of a long conversation that takes several unnecessary minutes and only leads to more confusion.  If this actually impacted results or the treatment, I’d do it happily.  
 

Botox vs Dysport: Conclusions

If there is one takeaway from this blog post, it is that these two products, in my practice, are totally interchangeable.  I offer both so that if a patient was expecting their treatment to last longer and would like to try another product, then I have another to offer.  Is this good for business?  Not exactly.  The more of a single product that you buy, the better deal you get from the company that sells it.  I offer multiple products so that I can give my honest views on them.  
 
Assume, for a minute, that I only offer Botox.  If you come in asking for “Dysport”, then I have the task of trying to talk you into having Botox instead (a classic “bait and switch“).  I don’t like this for my patients.  Some have a preference for whatever reason, and being able to offer anything they ask for is my priority, even though we pay in terms of not being able to get bulk discounts.
 

Botox vs Dysport: The Proof

Should you take my word for it?  Absolutely not.  Don’t trust anybody.  Peer-reviewed medical literature, however, is something you can trust.  Let me make the job easier for you and show you some articles I reviewed about Botox head to head against Dysport.  The conclusion I draw from these is that the products are interchangeable and produce a comparable clinical effect when used at the dilution ratios (1:3) that we use.  
 
Furthermore, think about the amount of revenue that is generated from these drugs, with these injectables being some of the most common cosmetic procedures in the world, and the potential gain one of the companies would have to show that their product is superior to the other(s).  There is a strong motivation (billions of dollars per year) to prove that your product is the best by showing a difference in a double blinded head to head study.  If there is a difference.
 

Medical Literature Citations of Botox vs Dysport:

 
*One study (not named here) that found Botox to be better at all time points against Dysport was not included because the main author received more than $180,000 from Allergan in just one year.