Botox or filler? The difference between the two treatments

Two different mechanisms

Botulinum toxin temporarily reduces the signal from nerve to muscle in the area where it is applied. Because the muscle contracts less, the lines formed by that muscle contracting over and over become less noticeable. It does not create volume in the skin; its effect is on muscle movement.

Hyaluronic acid filler, by contrast, is a gel-like substance placed beneath the skin at a specific depth. Hyaluronic acid is a molecule that also occurs naturally in the body. Filler supports volume that has decreased with age or for structural reasons, fills hollows and deep folds, and adds contour in some areas. It does not change muscle movement.

Consensus reports also emphasise this distinction: in the upper face, botulinum toxin is regarded as the core approach for muscle-related lines, whereas in the midface volume loss is the main concern, so fillers play a central role^[1].

Dynamic and static lines

An important distinction in deciding which treatment to consider is the type of line:

• Dynamic lines only become noticeable when the face moves: for example, lines between the brows when frowning, on the forehead when raising the brows, or at the corners of the eyes when smiling. Because these lines are caused by muscle movement, they are usually addressed with botulinum toxin^[2].
• Static lines are visible even when the face is at rest. Lines that have deepened over the years, the nasolabial folds running from the sides of the nose to the corners of the mouth, and volume loss in the cheek or temple area belong to this group. Where volume loss is the main concern, filler comes into consideration.

In practice, most lines are a mixture of both. For example, a deep line between the brows may be visible both because of muscle movement and because of a crease that has formed over time.

Timings and the treatment

Botulinum toxin treatment for expression lines takes about 5 minutes on average; beforehand, a topical anaesthetic cream is applied for about 30 minutes. The effect starts around day 3 on average, settles by days 7–10 and lasts about 5–6 months on average. The follow-up takes place within 30 days.

Filler treatment takes 10–20 minutes depending on the area; the anaesthetic cream is left on for about 30 minutes, and most fillers also contain a local anaesthetic. The effect is visible straight after the treatment. How long it stays depends on the product used, the area and the person; the follow-up takes place within 1 month. The amount needed (in ml) is determined at the examination.

All timings are averages and vary from person to person.

Can they be planned together?

Yes. Because the two treatments address different concerns, they can be planned together for a suitable patient. In a randomised split-face study on forehead and frown lines, botulinum toxin was found to be effective on its own, and the effect was reported to last somewhat longer when it was combined with filler^[3]. Which treatment is used in which area, and in what order, is decided at the examination.

Side effects and points to consider

With both treatments, the most common effects are redness, swelling and bruising at the injection site; these usually settle quickly^[2][4]. After botulinum toxin, a temporary drooping of the eyelid or brow may occasionally occur^[2]. With fillers, serious complications such as vascular occlusion (blockage of a blood vessel) have been reported, although rarely; for this reason the treatment should be carried out by a doctor with a thorough knowledge of facial anatomy^[5]. Hyaluronic acid fillers can be dissolved with the enzyme hyaluronidase if needed.

Treatment is not carried out during pregnancy or breastfeeding. Treatment is not carried out if there is severe active acne. If you take blood thinners, be sure to mention this at the examination; do not stop your medication without consulting your doctor.

Further reading

• Botulinum toxin (botox)
• Dermal fillers
• What to keep in mind after botox
• How long does hyaluronic acid filler stay?
• Preparing for an aesthetic treatment