If Increased Dilution/Fluid Can Cause Increased Temporary Welts with Botox, What's the Purpose of Excess Dilution?

The answers by Drs. Palmer and Case to my previous question make perfect sense, but given that increased dilution/fluid can cause increased (temporary) welts, what is the purpose of excess dilution?

Doctor Answers 6

Different volumes used to mix the botox

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Some doctors may want to use a lower concentration of Botox so it diffuses to a larger area based on the larger volume of liquid such as in the upper forehead. They may also find it more difficult to use the more concentrated form and deliver extremely small aliquots per injection.  Other doctors may prefer the precise placement of localized Botox so that they needn't  be as concerned about diffusion to neighboring structures. The other advantage of the less diluted form is that the temporary fluid bumps are much smaller and go away more quickly than when the larger volume of the less concentrated Botox is used.  Please remember that the important variable is the number of units of botox used and different doctors may use different numbers of units, but the same doctor would use  the same number of units regardless of which dilution and volume they use. 

Manhattan Dermatologic Surgeon
4.9 out of 5 stars 39 reviews

Diluting the Botox not necessarily ripping you off as long as paying per unit

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Some people will dilute Botox to a greater degree to treat areas where they want the toxin to diffuse more widely, such as the forehead, in hopes of getting a more even result.  As long as they are charging per unit Botox and not for the amount of fluid that each unit is diluted in, then they are not ripping off their patients.  A temporary side effect of using a greater dilution (such as 2cc per 100units of Botox as opposed to 1cc per 100 units) is that the larger amount of fluid will create more of a welt under the skin.  However, this should go away rather quickly.

Kathryn R. Shrift, MD (retired)
Minneapolis Dermatologic Surgeon

Overdiluting the Botox vial does NOT create "more units per vial" as some here say. That is a complete misunderstanding of math.

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I am confused about why two doctors here would say that "overdiluting" a vial of Botox, which either comes with 50 or 100 units, can create more "units per vial". This is mathematically untrue. It would simply mean that more liquid would be needed to carry a single unit into the skin, since the units are more spread out through more fluid. Legitimate treatment practices should not be able to make more money from a given vial by doing this, if they are honest about how many units they are using. This is why I feel that the practice of charging "per unit" and not "per volume injected" or "per area" usually is more reliable and fair.

A possible scientific reason to use more fluid to dilute a vial (which I do not do), is that more liquid in the initial injection may theoretically allow the given unit injected to spread further in the muscle tissue before attaching, to give a broader treatment area effect. This may actually be undesirable, depending on what is being done. So go only to an honest core specialty physician who can defend his/her practices in a way that make clear sense to you.

Jessica J. Krant, MD, MPH
New York Dermatologic Surgeon
4.7 out of 5 stars 41 reviews

Sadly, it's to make more money

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Dilution really should be done in the amount recommended by the manufacturer. However, some (less than honest) places, let's just say, will dilute the Botox more and offer savings to their patients on the price. This means that they can inject more units, but less effective units. A vial of Botox is either 50 or 100 units, when diluted properly. If a place puts excess solution in to dilute the Botox, they can get out 200 or more units, and say they are still injecting Botox because they are; however, the dilution amount is about 1/2 the effectiveness. It's all about saving the places money and giving people the allusion that they are getting great prices. In reality, what patients end up with is less effective treatments.

Botox Dilution

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There is no reason to dilute the Botox.  There are standard concentrations of Botox to use for various treatments.  Some people dilute the Botox more, but then it is less effective per given volume and also has an increased risk of spread.  


Good Luck.

Excess dilution of botox

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There is no real purpose in my opinion other than providing more volume with less units per volume which is less effective, but allows the potential to stretch the vial further (I.e. Treat more patients)

Todd C. Case, MD
Tucson Plastic Surgeon

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.