Can Botox Last Longer Than Six Months?

In general, the effects of neuromodulators, such as Botox, Dysport, and Xeomin, last about four to seven months (typically five to six months), and most people who return as needed will typically have to do so at these intervals in order to restore correction. However, there have been reports in the literature (and corroborated by my own clinical experience) that if an individual undergoes a series of about five neuromodulator treatments at a fixed four month interval (regardless of whether there is any return of the expression lines), the interval between treatments may be subsequently significantly lengthened.

A number of explanations have been proposed for this. These include that repeated treatment leads to atrophy of the the injected muscles and hence to more prolonged improvement. Another possible explanation is that repeated suppression of particular muscle groups allows for recruitment of other muscles and a kind of retraining not to make the types of expressions that led to the wrinkling in the first place. Whatever the actual explanation, undergoing the series can prove beneficial in this way--but only if the initial series is performed at the fixed four-month intervals.

Another method for prolonging the Botox effect is to combine its use with the injection of a filler. For example, it has been found that combining Botox with a hyaluronic acid filler in the scowl line area between the eyes can result in a one year correction--even after just one combined treatment session. I have personally found this to be the case, as well, in treatment the crow's feet lines on the sides of the eyes and the forehead worry lines. I have likewise found this combination, injected as microdroplets of each, especially useful for treating those difficult crepey, prune-like crinkles on the lower cheeks. 

Everyone is different, so there may be some variation as to how long Botox lasts.  I have definitely seen it last for more than 6 months in some patients.  I'm not sure if there was a difference in your last treatment as to how it was injected or how much was used.  Some people who have been treated over a long period of time do notice that it lasts longer.  Having had the Botox can also retrain people as to how they use their facial muscles, and this may contribute to its longevity.