Clinical studies from Allergan show BOTOX Cosmetic lasts about 2½ months to four months, but in reality BOTOX may last longer or shorter depending upon an individual’s metabolism, medications, age, dosage, and lifestyle.
Those who may have a shorter duration of Botox effectiveness include elite athletes and those who are on hormone therapy--particularly thyroid medications--as well as human growth hormone and other metabolic enhancing products. Those with longer potential for duration include those with slower metabolic rates as well as those with much larger dosages of Botox. There is some thought that really large doses may last much longer, but clinical studies are still lacking. We have had patients tell us anecdotally that their Botox is lasting up to six months—or even longer—and one must always keep in mind that clinical studies only give you the average duration for an individual and that actual patient duration is more in line with a bell shaped curve.
Another thing to note is that once an individual knows their own inherent average duration, that this tends to persist for future treatments in alignment with their baseline metabolism for Botox. Consequently if an individual runs on a four month cycle, typically they will continue running the four month cycle for future treatments.
One thing that can be done for an any patient who finds that their Botox duration is too short is to consider shifting to another neuromodulator such as Dysport, because the different product also has different carrier proteins which may have an effect in the duration of effectiveness and relaxation of the injected muscles, particularly in the case where there is some thought that a tolerance is developing for Botox. Another consideration is age because the age of the patient definitely impacts directly upon metabolism as one gets older and one’s metabolic rates tends to decrease.
Duration of action can also depend upon where one is injecting such as in the armpits for hyperhidrosis—typically with duration of action of about seven months in our clinical experience.