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Treatment
Neurotoxin injections
Small, precisely placed doses that relax muscles and quieten overactive nerve signals. Best known for softening lines — but the same molecule shapes a jawline, switches off sweating, and calms the flushing of rosacea.
What it is
A neurotoxin blocks the chemical signal that travels from a nerve to whatever it is instructing — a muscle to contract, a sweat gland to produce sweat, a vessel to dilate. Injected in tiny quantities into a chosen target, it turns down that one signal and nothing else.
The nerve endings regenerate over the following months, which is why the effect wears off and why treatment is repeated. Australian regulations do not allow me to name the products on a public page; in clinic I will tell you exactly which one I am using and why.
What brings you here?
The molecule is the same in every case. What changes is where it goes, how deep, how dilute and how much — and those four decisions are the whole of the treatment.
Wrinkles and laxity →Frown, forehead and lines that move
Eye rejuvenation →Crow's feet, brow position, under-eye crinkling
Facial shaping →Masseter slimming and a sharper jawline
Excessive sweating →Underarms, palms, soles, face and scalp
Rosacea →Flushing, burning and neurogenic rosacea
Keloid scars →An adjunct where tension drives the scar
Wrinkles and laxity
Neurotoxin treats lines caused by movement — the frown, the forehead, the lines that appear when you make an expression and disappear when you stop. Relaxing the muscle stops the fold forming, and over months the skin creased by that fold recovers.
Lines that are visible at complete rest are etched into the skin itself. Those need resurfacing or soft tissue injectables; relaxing the muscle softens them but will not remove them. The honest sequence is to treat movement first, then judge what is left.
What it will not do: tighten loose skin. Laxity is a skin and volume problem, not a muscle one. Used indiscriminately for laxity it makes a face look heavier, not lifted — which is why the lower face is dosed with real restraint.
- Fractional CO₂ laser →
- Collagen-stimulating injectables →
Eye rejuvenation
The eye area responds to very small doses. Relaxing the muscle that circles the eye softens crow's feet, and selectively relaxing its outer fibres lets the brow-lifting muscles win — a modest lift of the outer brow that opens the eye without changing your expression.
This is the area where technique matters most and where too much is immediately obvious. I treat conservatively, review at two weeks and add if needed, because a heavy brow or a dropped lid takes months to recover and cannot be reversed.
What it will not do: remove eye bags, lift excess lid skin or improve crepey texture. Those are surgical and resurfacing problems — and treating them with more units makes the result worse, not better.
- CO₂ eyelid resurfacing →
- Under-eye concerns →
Facial shaping
The lower face is where neurotoxin does something people rarely expect: it changes shape rather than smoothness. Relaxing the masseter — the large chewing muscle at the angle of the jaw — slims a square or heavy lower face over two to three months as the muscle reduces in bulk. It also settles clenching and the jaw ache that comes with it.
The second lever is the muscles that pull the lower face downward. Softening those depressors lets the elevating muscles sit unopposed, which lifts the corners of the mouth slightly and gives a sharper, cleaner jawline — small doses, carefully placed, with a visible change in the line of the jaw.
What it will not do: remove a double chin or change bone. Shaping works on muscle bulk and muscle pull. If the issue is fat or jaw structure, no amount of neurotoxin will address it and I will say so.
- Jawline definition →
- Teeth grinding →
Excessive sweating
This is the most reliable thing neurotoxin does. The nerve signal that tells a sweat gland to produce sweat is the same signal the toxin blocks, so treating an area switches sweating off almost completely for six to nine months. Underarms, palms, soles, face and scalp all respond.
Treatment for severe underarm sweating is partially covered under Medicare, and eligible patients are entitled to three treatments per calendar year. Criteria apply and we go through them at the consultation, including the topical treatments that need to have been tried first.
What it will not do: stop body odour caused by bacteria rather than sweat, or treat sweating caused by an underlying medical condition. Sudden-onset or one-sided sweating needs investigating before it is treated.
Rosacea
Neurotoxin has a genuine role here, and it is underused. It is especially useful in neurogenic rosacea — the subtype dominated by burning, stinging and flushing rather than spots — where the nerves themselves are driving the vessels. Around 30 to 50% of patients respond, which is worth knowing before you start: it is a trial, not a certainty.
The technique is microtox: a very dilute preparation placed superficially into the skin rather than into muscle. It reaches the small vessels, oil glands and nerve endings without affecting expression at all. Fixed redness and visible vessels still need vascular laser — microtox addresses the flush, the laser addresses the map.
What it will not do: clear permanent redness or thread veins, and it will not work for everyone. If there is no response after one properly dosed treatment, we stop and put the money into vascular laser instead.
Keloid scars
Keloids grow where a wound is under tension, and tension comes from the muscle underneath. Relaxing that muscle takes the pull off the healing scar, which is why neurotoxin is used as an adjunct in keloid-prone sites such as the chest, shoulders and jawline — and around a fresh wound in someone with a keloid history.
The evidence is modest and I will not oversell it. It sits alongside the treatments that do the heavy lifting: intralesional steroid, 5-fluorouracil, pressure, silicone and vascular laser for the redness. Used as part of that plan it helps; used alone it is not a keloid treatment.
What it will not do: flatten an established keloid. Nothing injected into the muscle beneath a mature scar will shrink it — that requires treatment placed into the scar itself, and often a combination over many months.
- Keloid scars →
- Vascular laser →
Everything below applies to all six
The appointment is the same whichever concern brought you here — only the dose, the depth and the dilution change.
What happens on the day
- Assessment and photographs
I watch the muscles work — frown, smile, clench — and photograph them. Dose follows anatomy, not a chart.
- Mapping
Injection points are marked. For sweating, a starch-iodine test is sometimes used to map exactly where the sweating is.
- Injection
A series of small injections with a very fine needle. Underarms and palms are iced or numbed first; the face usually needs nothing.
- Time
Ten to twenty minutes. You can drive, work and exercise the same day.
- Two-week review
The most important part. We photograph again, compare, and add units where the result is short. Starting low and reviewing is how you avoid looking treated.
What to expect afterwards
There is no downtime. There is a timeline.Nothing is visible at day two and the result is not complete until day fourteen. If there is an event, treat a fortnight ahead so there is room for the review.
Risks
| Effect | Frequency | Notes |
|---|---|---|
| Small bumps at injection points | Expected | Settle within an hour. |
| Bruising | Common | Small and short-lived; more likely around the eyes. |
| Headache | Uncommon | Usually after forehead treatment, lasting a day or two. |
| Asymmetry | Uncommon | Corrected at the two-week review with a few extra units. |
| Heavy brow or dropped lid | Rare | Recovers over weeks to months. Avoided with conservative dosing and accurate placement. |
| Compensatory sweating | Uncommon | Sweating shifting to an untreated area after hyperhidrosis treatment. |
| Reduced bite strength | Uncommon | After masseter treatment; temporary, and usually only noticed with tough food. |
| Allergic reaction | Very rare | Tell me about any previous reaction to an injectable treatment. |
It is straightforward to add units at the two-week review. It is impossible to remove them. Every plan here starts conservatively for that reason alone.
Who is and isn't a candidate
Suitable for most adults. Treatment is avoided in pregnancy, and in people with certain neuromuscular conditions.
Tell me beforehand if you take blood thinners, have had a previous reaction to an injectable treatment, or have had a result you disliked — knowing what went wrong changes how I dose you.
Also tell me if you have an infection in the area to be treated, as we will reschedule.
Don't come in for treatment two days before a big event. Fourteen days, not two.
Common questions
How much does it cost?
Who performs it?
Is any of it covered by Medicare?
How long does it take to work, and how long does it last?
Will I look frozen?
Does it hurt?
What is microtox?
Can it be combined with other treatments?
How I dose neurotoxin, and why the lower face is where it gets interesting
Dr Davin Lim · Dermatologist · The Skin Hospital, Sydney — Laser, Procedural and Anaesthetic Division
Most people arrive thinking of this as a wrinkle treatment with a fixed price and a fixed pattern. It is better understood as a way of turning down one specific nerve signal wherever that signal is causing a problem — a muscle contracting, a gland sweating, a vessel flushing. Once you think of it that way, the medical uses stop looking like a footnote.
Dose is a decision, not a menu
I watch the muscles work before I draw anything up. A strong frown in a man in his forties and a fine frown in a woman in her twenties are not the same problem and do not take the same number of units. Starting low and reviewing at two weeks costs one extra appointment and prevents the single most common bad outcome in this field, which is a heavy, immobile upper face that has to be waited out for four months.
The lower face: shaping rather than smoothing
The upper face is well understood. The lower face is where careful dosing changes the shape of a jawline. Relaxing the masseter reduces the bulk of a muscle that is often overdeveloped from clenching, and over two to three months the angle of the jaw softens and the face reads narrower from the front. It is one of the few non-surgical treatments that genuinely changes facial proportion, and it treats the jaw pain and morning headaches at the same time.
The depressors are the other half of that conversation. Several small muscles pull the corners of the mouth and the jawline downward, and they keep working as the face ages while the elevators weaken. Placing a few units into those depressors removes some of the downward pull, which lifts the mouth corners a little and defines the jaw line. Both are small-dose, precise treatments, and both are easy to overdo — an over-treated depressor group changes a smile, so this is territory for conservative dosing and a review.
Balance, again
Neurotoxin only addresses movement. It does not replace lost volume, it does not improve the quality of the skin, and it does not lift tissue that has descended. Used as the only tool, it produces a smooth, flat, slightly heavy face — the look people are describing when they say they can tell. Used as one of three or four modest interventions, alongside resurfacing for the skin and collagen-stimulating injectables for structure, it is close to invisible. That is the whole aim: a face that looks well, not a face that looks treated.
— Dr Davin Lim, Consultant Dermatologist
Conditions this treats
Related treatments
- Fractional CO₂ laser →
- Vascular laser →
- TCA CROSS →
- Collagen-stimulating injectables →
- All treatments →
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