Droopy eyebrows after Botox: why, how long and what to do
An eyebrow that droops after a botulinum toxin injection, known as brow ptosis, happens when the forehead muscle, the only one that lifts the eyebrows, is too relaxed. It is a known and temporary adverse effect. Here is why it appears, how long it lasts, what can help and when to see a doctor.
An eyebrow that drops by a few millimetres after an injection is enough to change your expression: the eyes look heavier, more tired, sometimes sterner. This brow ptosis is one of the best-known eyebrow problems after a botulinum toxin injection: a review of the literature lists it among the common adverse effects of botulinum toxin6. It is temporary. This page answers the seven questions people ask most often.
Why does the eyebrow drop after an injection?
The position of the eyebrow is a matter of balance. The forehead muscle pulls it up; it is in fact the only muscle that lifts the eyebrows and the upper face4. The muscles between the eyebrows and around the eye pull it down. When the forehead muscle is too relaxed, especially in its lower part, just above the eyebrows, the depressor muscles take over and the eyebrow drops4.
This is why the labels and reviews insist on the height of forehead injections. The label of a type A toxin asks practitioners not to inject the muscle fibres close to the rim of the eye socket, and to stay at least 2 cm above this rim2. A review recommends staying 2–3 cm above the rim of the eye socket, or 1.5–2 cm above the eyebrow, and treating the forehead together with the frown lines to keep the balance between the muscles that lift and those that lower4.
The labels describe this effect. With one type A toxin, brow ptosis is common after treatment of the forehead combined with frown lines1. With another type A toxin, it is uncommon2. With the short-acting botulinum toxin (serotype E), approved for frown lines only, it was reported in 0.13% of patients, which classifies it as uncommon3. These figures come from different trials: they cannot be used to compare the products.
How soon after the injection does it appear?
In trials of a type A toxin, brow ptosis appeared a median of 5 days after treatment1. It therefore follows the build-up of the toxin’s effect. With the short-acting toxin, whose first effects appear from 8 hours3, the time to onset of brow ptosis has not been published.
How long does it last?
As long as the effect of the product injected, since the eyebrow rises again when the forehead muscle regains its strength. With a type A toxin approved for the forehead, the effect has been shown for about 4 months after the injection1. With the short-acting toxin, the effect usually lasts 2–3 weeks3; this toxin has been approved in the European Union since 15 July 2026 and in Canada since 22 June 20267,8. These two profiles are summarised on the page that offers a comparison between long-acting and short-acting toxins; the page on how long the effect of an injection lasts gives durations product by product.
Is it reversible?
Yes. Brow ptosis disappears when the effect of the toxin wears off and the forehead muscle resumes its lifting role. The eyebrow then returns to its original position. No lasting effect is described in the sources we consulted.
Is there a treatment?
No product can restore strength to the forehead muscle: the toxin cannot be "reversed". In most cases, you wait for the eyebrow to rise again.
In some cases, the doctor may discuss a procedure on the muscles that pull the eyebrow down. A small study, carried out to lift the eyebrow rather than to correct ptosis after an injection, showed that relaxing these muscles, between the eyebrows and above the eyebrow tail, produced a lift of 1–3 mm in five of seven patients, about 1 mm on average5. The effect is therefore modest and inconsistent; this procedure has no aesthetic indication in the French labels and is decided case by case. The eye drops sometimes used for a drooping eyelid act on the eyelid, not on the eyebrow.
What should you avoid?
Do not try to compensate by having the forehead injected again: relaxing this muscle further would tend to make the eyebrow drop more. Do not shorten the interval between sessions: the label of a type A toxin states that intervals between two treatments should not be shorter than 3 months2. If the first injection was done with a short-acting toxin, a type A toxin injected less than 30 days afterwards has not been evaluated3. Finally, avoid mistaking a drooping eyebrow for a drooping eyelid: the two are not managed in the same way.
When should you see a doctor?
Talk to the doctor who performed the injection as soon as the eyebrow drops: they will confirm that it is the eyebrow and not the eyelid, and tell you what is possible. See a doctor promptly if the eyelid droops too, if you feel your field of vision is reduced, or if your vision is blurred or double. Write down the date of the injection, the areas treated and the day the eyebrow started to drop.
When to seek medical advice quickly
- Blurred or double vision
- Difficulty swallowing, speaking or breathing
Breathing, swallowing or vision problems: call the emergency services (15 or 112 in France).
A drooping eyebrow is often confused with a drooping eyelid after an injection, which has a different mechanism. Conversely, an eyebrow tail that sits too high is a Spock brow. A very relaxed forehead often goes with a frozen forehead.
Key points
- The eyebrow drops when the forehead muscle, the only one that lifts the eyebrows, is too relaxed4.
- In trials of a type A toxin, brow ptosis appeared a median of 5 days after treatment1.
- It lasts as long as the product’s effect: about 4 months for a type A toxin on the forehead, 2–3 weeks for the short-acting toxin1,3.
- The toxin cannot be reversed: you wait, and a procedure on the depressor muscles can be discussed case by case5.
Frequently asked questions
What is the difference between a drooping eyebrow and a drooping eyelid?
They involve different muscles. The eyebrow drops when the forehead muscle, which lifts it, is too relaxed4. The eyelid drops when the toxin reaches the muscle that lifts the upper eyelid, located inside the eye socket3. Both can make the eyes look heavy and can sometimes occur together; the labels list both among the adverse effects1,3. The doctor tells them apart by examining you, which guides what happens next.
Can a drooping eyebrow affect my vision?
Usually not: it mainly makes the eyes look heavier or more tired. When the eyebrow drops a lot, however, the skin of the upper eyelid can fold down over the eye and slightly narrow your field of vision upwards. If you feel you are seeing less well, need to raise your forehead to clear your view, or if your vision is blurred or double, see a doctor promptly.
Sources
- 1.SmPC of a type A botulinum toxin approved for aesthetic use in France (BDPM, CIS 68150775) (opens in a new tab) — French public medicines database (BDPM)
- 2.SmPC of a type A botulinum toxin approved for aesthetic use in France (BDPM, CIS 61592762) (opens in a new tab) — French public medicines database (BDPM)
- 3.Summary of product characteristics of the serotype E botulinum toxin approved in the European Union (EPAR annex I) (opens in a new tab) — European Commission (Union Register of medicinal products)
- 4.Borba A. et al., avoiding complications of upper face treatment with botulinum toxin: a practical guide, Aesthetic Plastic Surgery, 2022 (opens in a new tab) — Aesthetic Plastic Surgery
- 5.Huilgol S.C. et al., eyebrow lift with botulinum toxin, Dermatologic Surgery, 1999 (opens in a new tab) — Dermatologic Surgery
- 6.Kassir M. et al., complications of botulinum toxin and fillers: a narrative review, Journal of Cosmetic Dermatology, 2020 (opens in a new tab) — Journal of Cosmetic Dermatology
- 7.European public assessment report (EPAR) of the serotype E botulinum toxin (opens in a new tab) — European Commission (Union Register of medicinal products)
- 8.Canadian product monograph of the serotype E botulinum toxin (authorization date: 2026-06-22) (opens in a new tab) — Health Canada