Botulinum toxin softens expression lines by temporarily reducing activity in the muscles responsible. It is particularly effective on frown lines, forehead lines and crow's feet. Its main advantages are gradual results, a quick procedure and usually no social downtime. Its limitations are a temporary effect, the need for repeat injections and the risk of temporarily changing certain expressions if correction is excessive or unsuitable.
What are the advantages of botulinum toxin?
The main advantage of botulinum toxin is acting directly on the mechanism responsible for expression lines: muscle contraction. It does not fill wrinkles or increase facial volume.
When a muscle contracts, it pulls the overlying skin with it. Repeated movement initially creates dynamic wrinkles. Over time, these persist at rest.
Botulinum toxin temporarily reduces transmission between the nerve and treated muscle. Contraction decreases and the overlying skin is subjected to less strain.
This action particularly suits upper facial wrinkles. Effectiveness on glabellar, forehead and periocular lines is well documented.
Another advantage is adjustable treatment. The aim is not necessarily complete muscle immobilisation: dose and injection sites can be adapted to strength, facial anatomy and the movement the patient wants to retain.
Which wrinkles can botulinum toxin treat?
Botulinum toxin is mainly indicated for certain dynamic wrinkles, meaning wrinkles caused or accentuated by facial muscle contraction.
Indications include horizontal forehead lines, the frown line between the eyebrows and crow's feet appearing at the eye corners when smiling.
Other muscles may be treated in certain situations, for example neck platysmal bands. Indications, doses and injection depth then differ according to the area.
However, botulinum toxin does not treat every wrinkle. A wrinkle mainly associated with volume loss, tissue sagging or substantial skin changes will not be corrected by simply reducing muscle activity.
Can botulinum toxin give a natural result?
Yes. Botulinum toxin treatment can preserve expressions when doses and distribution suit facial dynamics.
A natural face does not necessarily mean one where all contractions have disappeared. Muscle activity can be reduced enough to soften wrinkles while retaining certain movements.
Assessment must therefore take place at rest and during expressions: frowning, raising the forehead and smiling. Two patients with similar wrinkles at rest may have very different muscle strength and contraction patterns.
Current recommendations specifically favour this personalised approach rather than routinely using the same sites and doses in every patient.
The desired degree of movement should also be discussed. Someone may wish to retain slight frowning or substantial forehead movement. Treatment should account for this preference.
Can botulinum toxin freeze the face?
Yes, an excessive reduction in muscle activity can give a frozen impression, but this is not an inevitable consequence of botulinum toxin.
The effect depends on dose, number of muscles treated, injection positioning and initial muscle strength.
The face functions through balance between muscles whose actions may oppose each other. At the eyebrows, for example, the frontalis raises them while others help lower them. Excessively changing one group can alter eyebrow position or eye-area dynamics.
Personalised treatment therefore determines which muscles should be weakened, by how much and which contractions should instead be preserved.
What results can you expect from botulinum toxin?
Botulinum toxin mainly acts on expression lines caused by repeated facial muscle contractions. It is particularly effective when wrinkles appear during movement.
When wrinkles start to show at rest, botulinum toxin can gradually soften them by reducing the contractions maintaining them.
However, deep, long-standing wrinkles may persist despite treatment. They are also associated with skin changes over time, particularly reduced collagen and elasticity.
Botulinum toxin therefore mainly reduces contractions responsible for expression lines and limits deepening. It is not always enough to eliminate a deeply marked wrinkle.
How long does botulinum toxin take to work?
The effect of botulinum toxin is not immediate. It appears gradually in the days after injection as neuromuscular activity decreases. The final result is reached after 7 days.
This gradual onset means results should not be assessed a few hours after the session. Movement continues changing after injections before stabilising.
The gradual nature of treatment also allows change to develop without a sudden alteration in the face.
How long does the effect of botulinum toxin last?
The effect of botulinum toxin is temporary and lasts between 4 and 6 months. Exact duration varies according to product, treated area, dose, muscle strength and individual response.
Muscle activity recovers gradually. As toxin action decreases, the muscle starts contracting again and dynamic wrinkles gradually reappear.
The temporary nature can be considered a disadvantage because treatment needs repeating to maintain its effect. It is also an advantage: a natural limit on a muscle dynamic change that may not suit the patient.
What are the disadvantages of botulinum toxin?
The main disadvantages are limited result duration, inability to reverse the action immediately and possible temporary changes to certain expressions.
Repeat sessions are the first constraint. Botulinum toxin does not provide permanent results.
Its second limitation is its mechanism. It treats a muscular component but does not restore lost volume, tighten sagging skin or correct every change in skin quality alone.
Finally, the result closely depends on injection strategy. Insufficient correction may leave substantial muscle activity; excessive correction may instead produce more immobility than desired.
What are the side effects of botulinum toxin?
Side effects after aesthetic botulinum toxin injections are most often local and temporary. Injection-site pain, redness, limited swelling or bruising may occur.
Headaches are also reported.
Other effects relate to the product's pharmacological action. If a muscle is weakened more than intended or a neighbouring muscle affected, asymmetry or a temporary change in a facial structure's position may appear.
Safety studies on aesthetic botulinum toxin type A broadly confirm a favourable safety profile, while identifying eyelid ptosis, brow ptosis and certain periocular disorders among possible adverse effects when injection technique is not mastered.
What are the risks of botulinum toxin?
Known aesthetic complications notably include eyelid and brow ptosis. Their frequency varies according to treated area, product, doses and studies.
Eyelid ptosis is temporary drooping of the upper eyelid. Brow ptosis is a lowered eyebrow, sometimes felt as heaviness around the eyes.
Regulatory data and clinical trials show that these complications are uncommon but real. Prescribing information also reports different adverse effects according to the injected area.
Serious systemic effects associated with spread of toxin action are also described in regulatory information, although they are not the effects usually observed with routine aesthetic treatments.
Why can the eyebrows or forehead feel heavy after an injection?
Forehead or eyebrow heaviness may occur when frontalis activity is reduced more than the patient's muscle balance allows.
The frontalis is the main eyebrow-elevating muscle. Some people spontaneously use it to maintain relatively high eyebrows. Strongly reducing its activity can then reduce eyebrow elevation and make the eye area feel heavier.
This explains why horizontal forehead lines should not be assessed and treated in isolation.
Before injection, eyebrow position at rest, frontalis strength, expressive movement and the action of eyebrow-lowering muscles should be observed. Upper facial treatment rests on this muscle balance, not simply the number of visible wrinkles.
Can an unwanted botulinum toxin result be corrected?
No treatment immediately reverses botulinum toxin action once established.
This differs from hyaluronic acid, which can in certain circumstances be broken down by a specific enzyme (hyaluronidase).
With botulinum toxin, management depends on the problem encountered. Asymmetry caused by persistent muscle activity can sometimes be improved with a small additional correction.
However, when a muscle has been weakened too much, injecting more product does not restore activity. Waiting for the effect to decrease gradually is generally necessary.
A cautious strategy therefore has an obvious advantage: insufficient correction can sometimes be supplemented, while excessive correction cannot be immediately removed.
What happens when botulinum toxin injections stop?
Stopping injections does not suddenly worsen wrinkles. As the effect disappears, muscles gradually recover activity and expression lines may return.
The face therefore does not suddenly become more wrinkled because treatment stopped. It gradually regains its muscle dynamics.
Meanwhile, skin ageing continues under the influence of age, sun exposure, genetics, dermal matrix changes and structural facial changes.
Gradually returning contractions after stopping should therefore not be confused with skin dependence on botulinum toxin.
Does botulinum toxin have long-term disadvantages?
Repeated treatments may reduce the strength and volume of regularly treated muscles, consistent with prolonged reduction of their activity.
This change does not necessarily have the same significance for every muscle. In certain indications, reduced strength or muscle volume may be part of the desired result. In others, excessive reduction could alter the area's aesthetic balance.
Needs therefore do not necessarily remain identical over the years.
At each session, strategy should be reassessed according to current muscle activity, previous treatment results and patient expectations.
Botulinum toxin or hyaluronic acid: what is the difference?
Botulinum toxin and hyaluronic acid address different mechanisms and indications.
Botulinum toxin temporarily reduces targeted muscle activity. It is therefore mainly used when muscle contraction contributes to the change being treated.
Hyaluronic acid is a filler notably used to restore certain volumes, alter certain projections, correct certain depressions or perform non-surgical lifting techniques.
Combining techniques may be appropriate in certain situations, but should not be automatic. Each treatment must address an identifiable anatomical indication.
Who cannot receive botulinum toxin injections?
Botulinum toxin injections are not performed during pregnancy or breastfeeding, with infection in the treatment area, known allergy to a product component or neuromuscular disease, particularly myasthenia gravis, Lambert–Eaton syndrome or certain motor neuropathies.
Particular caution is also necessary in patients taking medicines that may interfere with neuromuscular transmission, including certain aminoglycoside antibiotics, and with anticoagulant treatment because of increased bruising risk.
Botulinum toxin should also be avoided when a muscle is already substantially weak or changing its activity could worsen a pre-existing functional disorder.
Before injection, the doctor therefore checks neurological history, current treatments, possible local infection and previous botulinum toxin reactions. Without a medical contraindication, it remains necessary to confirm that botulinum toxin actually matches the problem: it is indicated when muscle activity plays a role in the wrinkle or aesthetic change observed.
How can you tell whether botulinum toxin suits your face?
Botulinum toxin is particularly appropriate when muscle activity is an important cause of the wrinkles or aesthetic change observed.
Assessment should therefore not concern the immobile face alone. The doctor also observes contractions during frowning, forehead raising and smiling to identify responsible muscles and their strength.
Consultation also determines what botulinum toxin cannot correct. Volume loss, sagging or substantial skin changes require a different approach.
In Geneva, the areas, doses and degree of correction should be adapted to facial anatomy and patient expectations. The aim is not to routinely eliminate all contractions, but to determine which movements are useful to reduce and which are better preserved.
Article written by Dr Valeria Romano
Dr Valeria Romano supports each patient through a comprehensive approach to facial, body and intimate aesthetics, as well as skin and hair quality. Every treatment is based on a personalised medical assessment.
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