Dose = Duration

Wish your toxin would last longer? Step number one: talk to your injector about your dose! All 4 current manufacturers of neurotoxin approved for use in the US agree that the duration of effect is directly related to dose delivered for the area of treatment. And while all products are measured in units, the “math” involved in the equivalency of a onabotulinumtoxinA (Botox) unit compared to an abobotulinumtoxinA (Dysport) unit can be tricky to explain. Add on top of the unit equivalency challenge the volume used to deliver the aid number of units may vary from injector to injector and even from area to area with the same injector. The math can be a mess! Bottom line, the number of units actually delivered per region is what is documented in the medical record, and what we use to measure our treatment on.


Certain muscle groups are stronger than others (think glabella and masseter)—the bulkier the muscle the more medicine that’s required to put it to sleep for a spell. Some muscles are thinner but cover large regions (think forehead or platysma)—they need enough product to spread throughout the region. And yet other muscle areas we do not ever want to overdo (think lip flip—overtreating that can keep you from enunciating your words, or controlling your spit—yikes!). Underdosing an area or treating with a small amount generally means it will not retain its relaxed effect as long as a larger dose would, but there may be good reason to do just that.


So, if you wish your toxin would last longer, the first thing is to evaluate whether or not you are receiving a dose sufficient for the muscle or the area. There are commonly accepted “usual” dosing for most areas, but every person is different, and dosing needs to be personalized. Consider too what product you are using, and what your expectations are. Movement is fine for most of us, we just don’t want to allow so much that the repetitive nature of the movement can contribute to etched in lines. And some wrinkles might be unloved but accepted because having the rainbow wrinkle above your brow is better than dropping your eyebrow and adding to upper eyelid hooding, eh?! Younger skin has healthy collagen and elastin stores, so wrinkles from movement may be better disguised than thinner, older, crepey skin.


Your injector has a complex job—they manage pharmacological, anatomical, technical skills all while using their artistic ability to finesse your treatment to match your goals, anatomy and dosing. Developing a good relationship with your injector is critical!