Botox for frown and forehead lines: what patients in Chiswick should know

The frown lines between the eyebrows and the horizontal lines across the forehead are the two areas that bring most people into an aesthetic clinic for the first time. They are also the two areas where botulinum toxin does its most predictable work, and where the difference between a considered treatment and a careless one shows up fastest on the face.

Chiswick and the surrounding parts of west London have a dense concentration of clinics, which is good for choice and unhelpful for comparison. The treatment is the same everywhere. The assessment is not.

How botulinum toxin works on the upper face

Botulinum toxin type A is a purified protein that temporarily blocks the chemical signal between nerve and muscle at the injection site. The treated muscle contracts less forcefully. Because the frown lines and forehead lines are folds created by repeated contraction of the muscles underneath them, reducing that contraction allows the overlying skin to lie flatter and, over time, to crease less deeply.

Two muscle groups matter here. The corrugator and procerus complex draws the brows together and down, producing the vertical frown lines often called the elevens. The frontalis muscle lifts the brows and produces the horizontal forehead lines. They work in opposition, which is the central fact of upper face treatment and the reason it is not simply a matter of injecting wherever a line appears.

Why the forehead cannot be treated in isolation

The frontalis is the only muscle that raises the eyebrows. If it is weakened too much, or treated without addressing the muscles that pull the brows down, the brow position can drop and the upper eyelid can look heavier. This is the mechanism behind most complaints of a heavy or hooded appearance after forehead treatment, and it is a dosing and assessment issue rather than a product issue.

It is also why careful practitioners often treat the frown complex and the forehead together, and why someone with a low resting brow or significant upper eyelid laxity may be advised to have very little forehead treatment or none at all. A practitioner who offers forehead treatment without examining brow position and eyelid skin has skipped the part that matters.

Dynamic lines, static lines and realistic outcomes

Look in a mirror with your face completely relaxed. Lines still visible are static lines, meaning the crease is now in the skin itself. Lines that appear only when you frown or raise your brows are dynamic. Botulinum toxin acts on the muscle, so it addresses dynamic lines directly and static lines only partially and slowly, as the skin is given a period without repeated folding.

Deep static lines usually soften rather than disappear, and they respond better to a combined approach over time, potentially including skin treatments that work on the dermis. Anyone promising that a set forehead line will vanish in a fortnight is describing a photograph rather than a face.

What the appointment involves

A first appointment should start with a history and an examination of the face at rest and in movement, as set out in our guide to what a good consultation looks like. The injections themselves take a few minutes. A fine needle is used, several small injections are placed per area, and most people describe it as a brief sting rather than pain. Anaesthetic is not usually needed.

Afterwards, small raised bumps settle within about twenty minutes. Bruising is possible, particularly between the brows. Standard aftercare is to stay upright for several hours, avoid rubbing or massaging the area, avoid strenuous exercise, saunas and heavy alcohol for the rest of the day, and to avoid facials or other facial treatments for about two weeks.

Onset, review and how long it lasts

The effect is not immediate. Most people notice change from day three to five, with the full result at around two weeks. That two week point is when a review should happen, because it is the only sensible moment to assess symmetry and decide whether a small adjustment is needed. A clinic that includes a review appointment as standard is a clinic that expects to be judged on the finished result.

Duration is typically three to four months in the upper face, shorter in some people, longer in others. Muscle strength, dose, metabolism and how expressive you are all play a part. Effects do not stop abruptly. Movement returns gradually, which is why many people book their next treatment when they notice lines starting to reappear on expression rather than at a fixed interval.

Risks worth understanding

Common and temporary effects include bruising, tenderness, a mild headache in the first day or two, and small areas of unevenness that usually resolve or can be adjusted at the two week review. Less common effects include eyebrow asymmetry and, rarely, a temporary droop of the upper eyelid caused by diffusion of product to a muscle that was not the target. Where that occurs it resolves as the effect wears off, generally over several weeks.

Treatment is not suitable during pregnancy or breastfeeding, in people with certain neuromuscular conditions, or where there is active infection at the injection site. This is exactly why a full history matters and why the prescription-only status of the medicine exists. Suspected side effects can be reported through the MHRA Yellow Card scheme.

The prescribing rule that patients often miss

In the UK, botulinum toxin is a prescription-only medicine. It cannot be advertised to the public by brand name, and it cannot lawfully be supplied without a prescriber making an individual clinical decision about the patient. A prescriber who has never seen you, assessing you from a form or a photograph, is a practice that professional bodies have repeatedly warned against. Our guide to who can legally inject in the UK sets out the position in full.

Ask who your prescriber is and whether they will see you. In a well run clinic the answer is immediate, because it is the same person holding the syringe.

What it costs in west London

In 2026, treatment of one upper face area in the UK commonly falls between about £150 and £350, with two and three area packages priced proportionally lower per area. Central and west London clinics sit towards the upper part of that range. A price substantially below it usually reflects a shorter appointment, a less experienced injector or a more dilute preparation, which we explain in our guide to UK treatment costs.

For a local example of how a Chiswick practice sets out its injectable treatment information and consultation process, see Dr Harry Clinic. As always, check the practitioner against the relevant professional register before you book, whichever clinic you choose.

Who should think twice

Some people are better served by waiting or by a different approach. Very low resting brows, heavy upper eyelid skin, an expectation of complete line removal, a first treatment scheduled a week before a wedding, or an underlying concern that is really about volume rather than movement are all reasons for a careful practitioner to slow down. Treating the wrong problem well is still treating the wrong problem, which is the subject of toxin, filler or neither.