Botox for frown lines (11s): units, cost and results

The frown lines are the vertical creases between the eyebrows, and the Botox Cosmetic label names them glabellar lines, associated with corrugator and/or procerus muscle activity — the paired corrugators and the single procerus.

Botox Cosmetic (onabotulinumtoxinA, Allergan/AbbVie) is FDA-approved in adults for the temporary improvement in the appearance of moderate to severe glabellar lines — one of four cosmetic areas on the label, alongside crow's feet, forehead lines and platysma (neck) bands.

No other cosmetic area is on it.

The glabellar-lines indication is where the product's cosmetic history starts: FDA approved it on April 12, 2002, by which point the toxin itself carried an initial U.S. approval dating to 1989.

The drug works by blocking acetylcholine release at nerve endings — the label credits cleaving of a protein called SNAP-25 — which produces a partial, localized reduction in muscle activity.

Reinnervation, the slow regrowth of those nerve connections, is what makes the effect temporary.

This page is one entry in the series map of all Botox areas, and the Botox guide covers the drug as a whole.

The label's candidate is an adult with moderate to severe glabellar lines associated with corrugator and/or procerus muscle activity.

Whether the treatment fits a particular person — medical history, medicines, how the brow moves — is a question for a licensed provider.

The label does draw some lines of its own.

Botox Cosmetic is contraindicated in people with known hypersensitivity to any botulinum toxin product or to any ingredient in the formulation, and it is not to be injected where there is an infection at the planned site.

People with neuromuscular disorders — the label names myasthenia gravis, Lambert-Eaton syndrome and ALS — may be at increased risk of clinically significant effects, and the label advises caution in people with pre-existing cardiovascular disease or swallowing or breathing problems.

On pregnancy and breastfeeding there are no adequate human data, and no data on whether the drug passes into breast milk.

Response is not uniform.

In exploratory analyses of the frown-line trials, 85% of 334 women were investigator-rated responders at day 30, against 59% of 71 men, and responses appeared lower in people 65 and older.

Cleveland Clinic adds a nuance about what a toxin alone can do: it describes Botox as treating dynamic wrinkles, the lines that show when the muscle contracts, and says patients whose lines remain deep even at rest may benefit from adding a dermal filler.

The labeled dose is 20 units, given as 4 units into each of 5 sites — two in each corrugator muscle and one in the procerus.

Adding areas changes the total on the label: forehead lines are treated together with the frown lines at 40 units in total (that pairing is its own topic in Botox for forehead lines), frown lines plus crow's feet comes to 44 units, and all three upper-face areas in one session total 64 units.

Dose is also one place a trial has looked past the label.

In a 2005 dose-ranging trial in 80 men, 40, 60 and 80 units to the glabella were consistently more effective than 20 units, with dose-dependent increases in response rate and duration and no increase in adverse events; the authors concluded that men benefit from starting doses of at least 40 units.

Those doses sit above the labeled 20 units, so they are a study finding to discuss with a provider, not a label recommendation.

Units are product-specific: the Botox Cosmetic label states its units cannot be compared to or converted into units of any other botulinum toxin product, so another brand's frown-line dose is not a different way of writing 20.

On money: Botox and other toxins are typically priced per unit or per treatment area, and the labeled dose acts as a floor for the unit count the area needs, so the cost works out to roughly units times a practice's price per unit.

We could not confirm a current national average price for neuromodulator injections — the ASPS statistics report for 2025 that we checked omits fees for minimally invasive procedures — so the numbers that matter are the ones on a practice's quote: its price per unit, and the units it plans for the areas it treats.

Onset comes first: the label says muscle relaxation in the frown-line area typically begins 1 to 2 days after injection and increases in intensity during the first week.

The fade is gradual, and the frown-line trials measured it.

In the label's studies, 405 adults received a single 20-unit dose, and investigators rated the lines none or mild at maximum frown in 74% at day 7, 80% at day 30, 70% at day 60, 48% at day 90 and 25% at day 120, against 2-6% on placebo.

About half still had a none-or-mild rating at the 3-month mark, and a quarter at 4 months.

Duration is the one figure the Botox Cosmetic label states for a cosmetic area, and it is written for this one: the duration of effect for glabellar lines is 3 to 4 months.

The label adds that the safety and effectiveness of dosing more often than every 3 months have not been clinically evaluated.

What changes duration — dose, sex, the individual — is its own topic, covered in how long Botox lasts.

The frown-line trials have their own row in the label's safety data.

In the glabellar trials (405 treated adults), adverse reactions at 1% or more and above placebo were eyelid ptosis in 3%, facial pain in 1%, facial paresis in 1% and muscular weakness in 1%.

Eyelid ptosis — a drooping upper eyelid — was the most common adverse reaction recorded for this area, against 0% on placebo.

On top of the trial rates, the injection itself can cause localized pain, swelling, redness, tenderness and bruising.

The label says adverse reactions generally occur within the first week and, while often transient, may last several months or longer.

Placement is where this area becomes a technique question.

To reduce the risk of eyelid ptosis, the label instructs injectors to avoid the area near the levator palpebrae superioris (the muscle that lifts the eyelid), to place lateral corrugator injections at least 1 cm above the bony supraorbital ridge, and to keep injections no closer than 1 cm above the central eyebrow.

Injecting botulinum toxin is the practice of medicine, as the American Med Spa Association (AmSpa) puts it — a prescription drug is being used to affect living tissue — so it belongs to a physician, an independent-practice nurse practitioner or another licensed professional working within their scope, under rules that vary by state.

The label adds its own requirement: those who administer Botox Cosmetic must understand the relevant neuromuscular and structural anatomy of the treated area — for the 11s, the corrugators, the procerus and the eyelid-lifting muscles nearby.

The CDC advises getting botulinum toxin injections only from a licensed, trained provider using product from an authorized source, and cautions that the procedure is not without risk even when FDA-approved product is given correctly.

Product authenticity is part of the check.

FDA warned on April 16, 2024, that counterfeit Botox had been found in multiple states and given to consumers for cosmetic purposes, with hospitalizations among the adverse events.

Genuine Botox Cosmetic shows U.S. License number 1889 on the vial and carton, and the label says not to use it if that number is missing or the tamper-evident features look broken.

For credentials, questions to ask and red flags beyond any one treatment area, how to choose a med spa works through the decision end to end.