Frown lines, forehead lines and crow’s feet
The vertical "11" lines between the brows, horizontal forehead lines and the fan at the outer eye all come from repeated muscle movement, and all soften with the same approach.
Facial lines come in two kinds, and telling them apart determines whether treatment will work. Dynamic lines appear when a muscle contracts and vanish at rest: the vertical eleven between the brows when frowning, horizontal forehead lines when the eyebrows raise, the fan at the outer eye when smiling. These result directly from repeated folding of skin over a contracting muscle, and they respond very well to relaxing that muscle. Static lines remain visible when the face is completely still. They begin as dynamic lines and become etched over years as skin loses collagen and elastin and stops springing back. Relaxing the muscle still helps a static line, by removing the force that deepens it and allowing some remodelling over time, but it will not erase one; a deeply etched line usually needs resurfacing, skin-quality treatment or a small amount of filler in addition. Most people in their thirties and forties have a mixture, and the consultation is largely about establishing which lines will soften with muscle treatment alone.
How we treat it
Treatment is a small number of precisely placed injections of botulinum toxin into the specific muscles producing the lines. The skill lies in the assessment rather than the injection: which muscles are dominant, how strong each is, how the brow is currently supported, and what will happen to brow position if a given muscle is weakened. The frontalis, for instance, is the only muscle that lifts the brow, so treating it too heavily or too low drops the brow and produces the heavy, closed look people fear. Conservative dosing with review at two weeks is the safer route, and a top-up then is straightforward, whereas over-treatment cannot be reversed and simply has to wear off. Onset is gradual, beginning around day three and complete by two weeks. The effect lasts three to four months for most people, sometimes longer with repeated treatment as the muscles gradually weaken from reduced use. The aim throughout is a face that still moves and still expresses.
Medically reviewed by Dr. Sherwin Hariri, MD, Medical Director & Chief Longevity Physician. Last reviewed August 2026.
This page is for information only and is not medical advice. Suitability for any treatment is determined at consultation.
Common questions
Will I still be able to make expressions?
Yes, if it is dosed properly. The intention is to soften lines while leaving movement intact, and that is achievable in the great majority of cases. The frozen appearance comes from over-treatment, not from the treatment itself. Starting conservatively and reviewing at two weeks is how that is avoided.
How long does it take to work?
It is not immediate. Onset begins around day three, with most of the effect by day seven and the final result at two weeks. That two-week point is when it should be assessed and topped up if needed. Judging the outcome at day four is judging it too early.
How long will it last?
Typically three to four months. Duration varies with dose, the muscle treated, metabolism and how physically active you are. Many patients find the interval lengthens with regular treatment, because muscles that contract less forcefully over time need less to keep them quiet.
Can it fix lines I have when my face is still?
Partly. Relaxing the muscle removes the force that deepens a static line and allows some remodelling over months, so lines usually soften. Deeply etched lines generally need something in addition: skin-quality treatment, resurfacing, or a small amount of filler placed into the line itself.
Other concerns
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