When looking into forehead Botox, you often see comments like, 'Dysport shows results faster and looks more natural.' It is true that when looking purely at onset time, price, and duration, Dysport is an attractive option. However, some accompany this with the advice to 'only get it if you don't have to worry about blepharoptosis (drooping eyelids).' Let's break down what this means and whether blepharoptosis is the actual standard you should be looking at.

While both are 'botulinum toxins', they work in slightly different ways

Both Botox (Allergan/AbbVie) and Dysport (Galderma) are Botulinum toxin type A*. They share the same mechanism of temporarily blocking signals from the nerves to the muscles to relax them. Consequently, they last for a similar duration (about 3 to 4 months).

The key difference lies in the size of the protein molecules and the resulting 'diffusion radius.' Because Dysport has a smaller and lighter molecular structure than Botox, it has a tendency to spread wider, even when the same amount is injected into the same spot.

* Botulinum toxin type A: A purified neurotoxin produced by Clostridium botulinum. It blocks the release of acetylcholine at nerve endings to prevent muscle contraction. Botox, Dysport, Xeomin, and Nabota all belong to this type A category.

Dysport spreads faster and wider than Botox

Dysport has two main advantages. First, rapid onset. While Botox takes 3 to 7 days to kick in, Dysport shows visible results in just 1 to 3 days. Second, a wider diffusion radius*. When injected at a single point, Botox works within a 3 to 5 mm radius, whereas Dysport spreads out 5 to 10 mm.

* Diffusion radius: The distance botulinum toxin spreads from the injection site to the neighboring muscle fibers. This varies depending on molecular size and protein structure. A narrow radius allows for precise relaxation of a targeted spot, while a wide radius relaxes a larger area evenly at once.

When you want to evenly relax a broad muscle like the frontalis (forehead muscle) and desire quick results, Dysport’s 'fast and wide' spread becomes a major advantage. It is excellent for minimizing injection points and creating a natural, even distribution.

This 'wide spread' can be a drawback for those with muscle dependency

That same 'wide spreading' characteristic can work against you if you depend heavily on your forehead muscles to open your eyes. The strategy of 'targeting only the upper forehead while preserving the sides' (which we explored in Part 3 of our series) is difficult to execute precisely with Dysport. Even if injected only at the top, the product spreads 5 to 10 mm downward and outward, eventually reaching the sides of the forehead and just above the eyebrows.

This is why practitioners often say, 'It’s best to get Dysport only if you don’t have to worry about drooping eyelids.' To be precise, it means 'for those who rely heavily on their forehead muscles, Dysport’s high diffusion increases the risk of pseudoblepharoptosis (temporary heaviness or drooping of the eyelids).'

It is unrelated to true blepharoptosis — muscle dependency is the real criteria

This is a common point of confusion. The accurate standard isn't 'you shouldn't get Dysport if you have blepharoptosis,' but rather 'be cautious with Dysport if you rely heavily on your forehead muscles to open your eyes.'

True blepharoptosis (a structural weakness of the levator palpebrae superioris muscle itself) cannot be caused by Botox or Dysport. Neither of these products comes into direct contact with that muscle. What we actually worry about is pseudoblepharoptosis (eyelid heaviness due to relaxed forehead muscles), which can happen with any toxin if you have a strong dependency pattern. Dysport simply carries a slightly higher risk in these specific cases due to its high diffusion.

Which product is right for you?

We choose the appropriate product by combining your self-assessment results with your natural facial expressions. Here is a summary table:

There is no absolute 'right' choice between Dysport and Botox. The clinical standard is to gauge your level of forehead dependency first, and then select the product accordingly. While the final choice should always be made during a consultation with your doctor, knowing these standards beforehand will make your decision-making much clearer and easier.