Botulinum toxin on the face: how it works and what to expect
How botulinum toxin acts on the muscles of facial expression, the areas it is applied to, when the effect starts and how long it lasts, aftercare and possible side effects.
Botulinum toxin is injected into the muscles of facial expression to reduce, temporarily, the dynamic lines produced by their repeated movement — between the eyebrows, across the forehead, at the corners of the eyes. The effect begins within a few days, wears off over a few months and leaves no permanent change.
What botulinum toxin is and how it acts
Botulinum toxin is a neurotoxin obtained from the bacterium Clostridium botulinum. Several serotypes exist in nature; the one most used in cosmetic and medical practice, and clinically the most effective, is type A.
In the muscle it is applied to, it temporarily blocks the release of acetylcholine at the junction between the nerve ending and the muscle. With that block in place the contraction signal cannot reach the muscle, and the muscle relaxes temporarily. Over time the nerve endings form new connections and muscle function gradually returns — which is why the effect is temporary rather than permanent.
Where on the face it is used
Treatment targets the "dynamic" lines that develop from repeated contraction of the muscles of expression. For deep, static lines present at rest, botulinum toxin alone may not be enough and is considered alongside other methods. The main areas are:
- Lines between the eyebrows (glabella): targeting the muscle group that draws the brows together.
- Forehead lines: applied to the muscle responsible for the horizontal lines, in small, multiple doses so as to avoid dropping the brow.
- Crow's feet: applied to the outer fibres of the circular muscle around the eye.
- Bunny lines on the bridge of the nose: targeting the muscle responsible for the creases at the root of the nose.
- Fine lines above the lip: applied superficially and at very low dose.
- Downturned corners of the mouth: relaxing the muscle that pulls the corner downwards can produce a slight lift.
- Chin: applied to the muscle responsible for a dimpled or puckered appearance.
- Jawline and neck: considered in selected cases to support the contour of the jaw.
- Masseter (the chewing muscle): may be used for clenching and grinding, and to slim the lower half of the face.
When the effect starts, and how long it lasts
Muscle relaxation generally becomes noticeable within the first 2-3 days. The final result appears within 10-14 days. On the face the effect lasts on average 3-4 months; depending on the muscle and the dose it can last longer in some patients. In the lower half of the face — around the lips and other more mobile areas — the effect is generally shorter. As new nerve connections form, the effect diminishes gradually and muscle function returns completely.
Aftercare
- stay upright for the first 2-4 hours, avoiding bending forward or lying on your back
- do not massage or rub the injection site for the first 24 hours
- avoid heavy exercise, yoga and pilates on the day and for the following 24-48 hours
- avoid make-up for the first 12-24 hours, and do not wash the area vigorously
- stay away from very hot environments — sauna, steam room, solarium — in the first days
- avoid alcohol for the first 12-24 hours
Who it is not suitable for
- pregnancy and breastfeeding
- neuromuscular junction disorders such as myasthenia gravis, Eaton-Lambert syndrome and ALS
- active infection (bacterial, viral or fungal) or a skin condition such as eczema in the treatment area
- a known allergy to the components of the toxin
- serious bleeding disorders
- certain medicines (for example antibiotic groups affecting neuromuscular transmission) — always tell your doctor what you are taking
Assessing these situations requires a detailed history taken by the doctor beforehand.
Possible side effects
Side effects are generally mild and temporary, and depend largely on technique and on knowledge of the anatomy:
- temporary redness, bruising or slight swelling at the injection site
- a short-lived headache
- rarely, temporary drooping of an eyelid or eyebrow if the toxin spreads to a neighbouring muscle
- rarely, a temporary asymmetric appearance at the ends of the eyebrows
- with excessive doses, a loss of naturalness in facial expression
Most of these settle on their own within a few days to a few weeks.
Frequently asked questions
Does it make the face look frozen?
With the correct dose and technique, the aim is to weaken the muscle rather than paralyse it, so expression is preserved. A frozen look is generally associated with excessive dose or treatment over too wide an area.
Is it habit-forming? What happens if you stop?
Botulinum toxin is not habit-forming. If treatment is not repeated, the nerve endings form new connections over time and muscle function — and therefore the lines — gradually return to how they were before.
Can it be repeated frequently?
Repeating at very short intervals — for example less than three months — can lead the body to develop resistance to the toxin and to a loss of effect over time. The interval should be judged by a doctor.
See also botulinum toxin.