Botox or fillers: how they differ and when each one is used

What each one does: relaxing the muscle versus filling

Botox and hyaluronic acid fillers are both given as small injections in the face and take little time, but they work in very different ways and are used for different problems.

"Botox" is the popular name for botulinum toxin type A, taken from the brand name of one of the medicines that contain it. It is a prescription-only medicine that temporarily and reversibly blocks the signal from the nerve to the muscle into which it is injected. The muscle contracts less, the skin over it stops creasing so strongly and the lines that appear when you make facial expressions soften.

As for hyaluronic acid, it is a substance that is already part of the skin and holds on to water. The fillers used in aesthetic medicine are hyaluronic acid gels that are injected to restore volume where it has been lost, soften a fold or define a contour. They are not medicines but medical devices, which must carry the CE mark, and they are resorbable: the body gradually breaks them down over time.

Put simply: the toxin acts on the movement that creates the wrinkle; hyaluronic acid acts on the volume and support of the skin.

Which wrinkles and areas each one treats

The first step is to tell apart two types of wrinkle:

• Dynamic or expression lines. They appear or deepen when you make facial expressions: when you frown, smile or raise your eyebrows.
• Static wrinkles and volume loss. These are visible when the face is at rest, such as the folds that run from the nose to the corners of the mouth, or areas that have sunk or lost definition over the years.

For cosmetic use, botulinum toxin is authorised for the temporary improvement of vertical frown lines between the eyebrows, crow's feet and horizontal forehead lines, in other words the upper third of the face. On a wrinkle that is already etched in at rest, its effect is only partial. Outside aesthetics it also has medical uses, which are assessed separately.

Hyaluronic acid is used mainly in the lips, nasolabial folds and the corners of the mouth, cheekbones, chin and jawline and, in selected cases, under the eyes or on the backs of the hands. There are also more fluid formulations designed to improve the hydration and quality of the skin rather than to fill.

How long Botox and fillers last

Any figure for how long the effect lasts is only a guide, because it depends on the area, the dose or the product, the muscles and each person's metabolism.

With hyaluronic acid there is no single figure. Each product has a different density and resistance, and a filler in the lips, which are constantly moving, does not behave in the same way as one in a more stable area. We are talking about months, and the doctor will explain what you can expect in your case. Because the swelling in the first few days can mask the result, the result is assessed later, at a follow-up appointment.

Can you combine Botox and fillers?

Yes, and it is common, precisely because they treat different things. The same person may have lines between the eyebrows, which respond to the toxin, and a fold that has lost volume, which is treated with hyaluronic acid. Combining them is not about piling up treatments, but about choosing what makes sense for each area.

When they are combined, it is the practitioner who decides what is done first, in which areas and whether it is best to do it in the same session or at separate appointments. And sometimes the conclusion is that neither is needed: if what concerns you is the texture of your skin, a dull complexion or dark spots, other treatments, such as a chemical peel, may be a better fit.

Side effects and when they are not recommended

Botulinum toxin

According to its summary of product characteristics, common side effects include headache, a drooping eyelid and reactions at the injection site, such as pain, swelling, redness or small bruises. Very rarely, the effect has been reported to spread beyond the treated area: if you have difficulty swallowing, speaking or breathing after treatment, see a doctor immediately.

It is not given to people who are allergic to the toxin or to any of the ingredients of the medicine, to people with myasthenia gravis or Lambert-Eaton syndrome, or when there is an infection in the area to be treated. Nor is it recommended during pregnancy or breastfeeding.

Hyaluronic acid

The most common effects are bruising, redness, swelling, pain or tenderness in the area, which usually settle within days or a few weeks. The most worrying complication, uncommon but serious, is accidental injection into a blood vessel, which can damage the skin by cutting off its blood supply and, in rare cases, cause problems with vision, including blindness, or a stroke. That is why injecting a filler is a medical procedure that requires a sound knowledge of anatomy and knowing how to act if a complication arises; for example, the gel can be dissolved with an enzyme, hyaluronidase. If after a filler you notice severe pain, pale or bluish skin or any change in your vision, go to the emergency department without waiting.

Before treatment, tell the practitioner if the skin in the area is inflamed or infected, or if you have a blood clotting disorder, severe allergies or an allergy to lidocaine, the anaesthetic contained in many fillers. And whatever the treatment, say what medication you take, especially anticoagulants or antiplatelet drugs: do not stop taking them on your own.

Why it always starts with a medical assessment

Neither of them is chosen from a catalogue. The toxin is a prescription medicine and the filler is a product implanted in the skin: in both cases, whether it is indicated is decided by a professional after assessing your case.

In that first consultation, your medical history, allergies and the medication you take are reviewed; your face is observed at rest and in movement, to distinguish what is expression and what is volume, and you talk about what concerns you and what it is reasonable to expect. It is also the moment to ask which product will be used and what the follow-up will involve. Sometimes the honest answer is that nothing needs treating.

If you are considering either of these treatments, on our Aesthetic medicine page you will find out how we work and how to book an initial assessment.