Forehead wrinkles: why they appear and how to treat them

Why do horizontal forehead wrinkles appear?

Try this. Look at yourself in the mirror. Relax your face completely. Now raise your eyebrows. The horizontal lines appear.

This happens because the frontalis muscle contracts and lifts the eyebrows, folding the skin of the forehead.

When we are young and the skin retains good elasticity, those lines tend to disappear once the muscle relaxes.

But we repeat this movement thousands and thousands of times.

Over time, other factors come into play: progressive loss of collagen, changes in elastin, photoageing, a reduced capacity for skin recovery, and structural changes inherent to ageing.

As a result, a line that initially appeared only with movement may begin to remain visible at rest.

We move from a dynamic wrinkle to a wrinkle with an increasingly static component.

The frontalis muscle has a very important function

This is the key point.

The frontalis muscle does not only produce wrinkles. It also lifts the eyebrows.

In fact, it is the primary elevator muscle of the eyebrows.

And this means we cannot treat it as though it were simply a troublesome muscle we want to paralyse.

Because around the eyes there is a balance between muscles that elevate and muscles that lower the eyebrows.

Recent literature on the treatment of forehead lines emphasises precisely the importance of assessing the shape and position of the eyebrows, individual anatomy, muscle strength, and the balance between the frontalis and the depressor muscles before deciding on the injection points and the intensity of treatment.

Why do some people use their forehead a great deal?

Because not everyone moves their face in the same way.

Some people have a very powerful frontalis. Others constantly raise their eyebrows when they speak.

But there is another particularly interesting situation.

There are patients who use the frontalis to keep their eyebrows lifted and their eyes more open.

There may be a naturally low eyebrow position, or changes related to the ageing of the periocular region.

The patient then unconsciously contracts the frontalis to compensate.

If we simply block that muscle too much, we can erase the wrinkles… but we can also remove part of that compensation.

And the patient may feel that their eyes or eyebrows are heavier.

That is why we must not treat only the wrinkle.

When I assess forehead wrinkles, I do not just look at the lines.

I observe: how the eyebrows sit at rest, what happens when the patient raises them, whether there is asymmetry, how strong the frontalis is, what is happening at the glabella, how the muscles around the eyes behave, the height of the forehead, and how the entire upper third changes when the patient makes expressions.

The modern treatment of forehead lines is based precisely on this individualised functional assessment.

No two foreheads are exactly alike. That is why there should not be an identical treatment pattern for everyone.

So, what is the main treatment?

When the lines are fundamentally dynamic, the primary tool is botulinum toxin.

Botulinum toxin temporarily reduces the contraction of the treated muscle and can soften the lines produced by that movement. Botulinum toxin products are used to temporarily improve different facial lines, including forehead lines depending on the product and its authorised indication.

But here another fundamental idea emerges: the goal should not be to completely paralyze the forehead.

What are we looking for, then?

We are looking to neuromodulate.

That is: to reduce excessive muscle activity, soften the lines, maintain balance between the muscles, and preserve a natural expression.

A person should still be able to express themselves. To look surprised. To smile. To move their eyebrows.

Well-performed aesthetic medicine should not transform an expressive face into a mask.

Where is it injected?

This is where the treatment must be medical and individualized.

The injection points, depth, distribution, and amount of toxin depend on each patient's anatomy and muscle pattern.

A recent review dedicated specifically to dynamic forehead lines highlights precisely the importance of individualizing doses, depth, and point distribution according to anatomy, muscle vectors, and treatment goals.

That is why I do not believe in: 'X units for every forehead.' Nor in: 'the same five points for everyone.' Anatomy decides.

Why can an eyebrow drop after a treatment?

Because we have discussed something fundamental: the frontalis elevates the eyebrow.

If we reduce its activity too much — especially in a patient who relies heavily on this muscle to maintain their eyebrow position — we can produce a sensation of heaviness or descent.

Eyebrow and eyelid ptosis are among the known adverse effects of botulinum toxin treatments in the upper facial third.

That is why the treatment does not consist solely of knowing where a wrinkle is. It consists of understanding what function the muscle we are treating serves.

What about the glabella?

It matters too.

Glabella wrinkles arise primarily from depressor muscles that act differently from the frontalis.

That is why the forehead and the glabella are part of a balance.

In certain patients it makes sense to assess both regions together. Not because both always need to be treated. But because they are functionally related.

A thorough assessment of the upper third does not look at muscles in isolation. It looks at forces that balance each other.

How long does it take to see results?

Botulinum toxin does not produce its full effect immediately after injection.

The effect begins gradually over the following days and then reaches its clinical result.

The AAD notes that many patients begin to notice results in approximately 3 to 7 days, although the effect continues to evolve afterwards.

That is why we should not evaluate the definitive result the day after treatment.

How long does it last?

The effect is temporary.

Duration varies between individuals, product, dose, area, and muscular activity.

As a general reference, the AAD notes that the results of botulinum toxin typically last approximately 3–4 months, although they may last longer in some people.

After that, muscular activity gradually returns.

What happens if the wrinkle is already set even when the forehead is at rest?

Here the problem changes.

If a line has been forming over years, there may come a point where it remains visible even when the muscle is completely relaxed.

At that stage, we are dealing with a static wrinkle.

Botulinum toxin can prevent the muscle from continuing to fold that area intensely, and it can allow the line to gradually soften.

But a deep static wrinkle may not disappear completely with neuromodulation alone.

So we need to start thinking about something else as well: skin quality.

What can we do about a static wrinkle?

Depending on the skin, we can consider complementary strategies.

For example: topical treatments, retinoids when indicated, peelings, fractional lasers, dermal remodelling treatments, or certain regenerative approaches.

Here the goal is no longer simply to reduce movement. We want to improve skin that has been folding on itself for years.

And what about laser?

It can be particularly interesting when there are: fine static lines, photoageing, irregular texture, or alterations in skin quality.

A fractional laser does not act on the frontalis muscle. It acts on the skin.

That is why it can complement neuromodulation when two problems exist simultaneously: movement + skin ageing.

And what about peelings?

Peelings can improve certain superficial alterations and form part of a rejuvenation strategy.

But again: a peeling cannot prevent a very powerful frontalis from contracting.

If the primary cause is muscular, we need to act on the muscular component.

What about retinoids?

Topical retinoids can progressively improve certain signs of photoaging and fine lines.

But they require consistency and time.

They do not replace botulinum toxin when significant dynamic lines are present. They are different tools for different problems.

Can forehead wrinkles be filled with hyaluronic acid?

This question deserves a specific explanation.

Technically, there are very select situations in which fillers may be used in certain regions.

But hyaluronic acid is not my first tool for a dynamic horizontal forehead wrinkle.

Why?

First, because if the wrinkle appears mainly due to muscle contraction, it makes more sense to treat the mechanism that produces it.

Second, because the forehead is a region with a vascular anatomy that requires particular caution.

The FDA, for example, warns that the injection of fillers into the forehead is not among its approved uses, and notes that accidental intravascular injection of fillers can cause serious complications.

That is why: a line does not automatically mean we need to fill it.

Can wrinkles be prevented from becoming deep?

To a certain extent, we can modify some of the factors involved.

The most obvious one is sun exposure. Photoprotection helps reduce cumulative photoaging.

We can also take care of skin quality and, in selected patients, modulate excessive muscle activity before certain dynamic lines gradually become static ones.

But this does not mean that everyone should start botulinum toxin at age 20, 25, or 30. There is no universal age.

So, does 'preventive Botox' actually exist?

It is an expression widely used on social media.

It has a certain physiological logic: if we reduce the repeated folding of the skin, we can minimize one of the mechanisms that contributes to the deepening of certain lines.

But that does not mean: 'the sooner, the better.'

The indication should depend on muscle activity and the patient's characteristics, not simply on their age.

Does one have to wait until a wrinkle is deep?

Not at all.

We can intervene when a line is starting to become a concern for the patient and there is a reasonable indication.

Aesthetic medicine should not operate at two extremes: 'you have to start at 20' or 'you have to wait until the wrinkle is deep.'

We evaluate each face.

Why is one eyebrow sometimes higher than the other?

Because our faces are not perfectly symmetrical.

We may have: differences in muscle strength, different eyebrow positions, different contraction patterns, or minor structural asymmetries.

And here is something fundamental: those asymmetries must be assessed before any treatment.

Because if we do not know what was there beforehand, we may later attribute to the treatment something that was already part of the patient's anatomy.

Is a completely smooth forehead a good result?

Not necessarily.

If achieving a completely smooth forehead has produced: heavy brows, a total absence of expression, an altered brow shape, or a different look, we have exchanged one wrinkle for another problem.

For me, the goal is different: to soften without erasing expression.

What I want you to remember

Forehead wrinkles arise primarily from the interaction between: muscle movement + skin ageing + time.

The frontalis creates the horizontal lines when it raises the eyebrows. But that same muscle serves a purpose: it maintains and lifts the position of the eyebrows.

That is why treating the forehead correctly does not mean chasing every line with a needle.

We need to assess: the forehead, the eyebrows, the glabella, the eyes, the asymmetries, and the way that particular person gestures.

If the wrinkle is essentially dynamic, botulinum toxin is usually our main tool. If a static line already exists, we may also need to work on skin quality. And if there is photo-ageing, we can incorporate additional strategies.

That is why when someone asks me: "How can we get rid of forehead wrinkles?", my goal is not to leave the forehead immobile. It is to find the point at which we achieve: less wrinkle, but the same person.