How Long Does Xeomin Last? What the Label Rules Out

Xeomin's FDA prescribing information reports a median onset of treatment effect within two to seven days after injection and a typical duration of up to 12 to 16 weeks per treatment, adding that duration varies between individuals. The same label sets a minimum retreatment interval that changes with the condition treated: no more frequently than every three months for upper facial lines, no more frequent than every 12 weeks for cervical dystonia and for blepharospasm, no sooner than every 12 weeks for upper limb spasticity, and no sooner than every 16 weeks for chronic sialorrhea. Duration was not a primary endpoint in the pivotal trials; the cosmetic ones measured treatment success at Day 30. No number on the label forecasts how long one area on one face will hold.

Which indication were you actually treated for?

Xeomin (incobotulinumtoxinA, Merz) carries five approved indications in the United States, per the prescribing information posted on DailyMed and revised in June 2026. Each one arrives with its own dose, its own assessment visit, and its own retreatment floor.

| Indication | Labeled dose | Minimum retreatment interval | What the trial measured, and when | |---|---|---|---| | Upper facial lines (glabellar, horizontal forehead, lateral canthal) | Up to 64 Units combined: 20 GL, 20 HFL, 24 LCL | No more frequently than every three months | Treatment success at Day 30 | | Cervical dystonia | 120 Units initial | Generally no more frequent than every 12 weeks | TWSTRS total score at Week 4 | | Blepharospasm | 50 Units initial in treatment-naïve patients (25 per eye) | No more frequent than every 12 weeks | Jankovic Rating Scale severity at Week 6 | | Upper limb spasticity (adults) | Up to 400 Units | No sooner than every 12 weeks | Ashworth Scale response at Week 4 | | Chronic sialorrhea (adults) | 100 Units (30 per parotid, 20 per submandibular) | No sooner than every 16 weeks | Salivary flow rate at Week 4 |

Masseter injection is absent from that list. So are the jaw, the neck, and the lower face. Clinics treat those areas as off-label practice, competently and legally. There is still no labeled dose, no labeled interval, and no trial endpoint to hold a masseter result against.

I got this wrong myself. Auditing a clinic price menu in 2023, I let a "Xeomin jaw slimming" line stand as label-supported in a published comparison because the vial matched the entry two rows above it. A reader carried my chart to her injector and came back with the correction. I reissued the audit with a retraction note, the expensive way to learn that a product name on a menu tells you nothing about which evidence applies.

"Lasts" is at least three different measurements

There is the day the effect starts, which the label puts at a median of two to seven days. There is the day the result was measured in the trials, which for upper facial lines was Day 30 after the first treatment. There is the day a person looks in a mirror and decides the result is gone. And there is the day the treated muscle genuinely returns to its baseline severity score, which usually arrives later than the mirror verdict.

Only the first two are on the label. The third is a judgment, and the fourth was followed but not reported as a duration endpoint: subjects in the Xeomin upper facial lines trials were tracked for 120 days before entering the open-label extension.

Here is the strongest case against my position, and it is a fair one. The label does say up to 12 to 16 weeks. Three to four months sits inside that window. Injectors book on that cadence and most cosmetic patients find it roughly right. All true. What the slogan drops is that the 12-to-16-week sentence lives in a section on monitoring effectiveness and covers every indication the product carries, from a glabella to a salivary gland. "Up to" marks a ceiling. Underneath it sit four different retreatment floors, and a single quarterly cadence erases the distinction between a three-month floor and a 16-week one.

What the Day 30 numbers actually report

The upper facial lines program ran two randomized, double-blind, placebo-controlled trials, registered as NCT04594213 and NCT04622254 and reported in the label as Trials 1071 and 1070, with 730 treated adults between them. Severity was rated at maximum contraction on the five-point Merz Aesthetic Scales by both the investigator and the subject. Success required both a score of none or mild and at least a two-grade improvement from baseline, on both raters' scores, at Day 30.

In Trial 1071, the 64-Unit arm reached that bar in 53% of subjects at the glabella, 67% at the forehead, and 53% at the lateral canthal lines. In Trial 1070, the same 64-Unit regimen produced 49%, 58%, and 33%. Placebo reached 0% in every area in both trials.

Set those two trials side by side. Same product, same doses, same endpoint, same scale, two trials run in parallel, and lateral canthal success lands at 53% in one and 33% in the other. A third arm in Trial 1070 that treated only the crow's feet with 24 Units returned 24%. That spread is not a patient's metabolism. It is the ordinary variability of a rated cosmetic outcome, published in the product's own label.

The older glabellar-only trials, GL-1 and GL-2, used a four-point scale and a composite requiring a two-grade improvement from both raters at Day 30. They returned 60% (111 of 184) and 48% (87 of 182), against 0% for placebo in both. Investigator ratings alone ran higher, at 77% and 71%.

None of those figures is a duration. Every one of them describes a single visit one month after injection.

Why Xeomin and Botox Cosmetic will not compare on units or percentages

Section 5.2 of the Xeomin label is one sentence long: potency Units of Xeomin are specific to the preparation and assay method used, and cannot be compared to or converted into Units of any other botulinum toxin product assessed with a different assay. The Botox Cosmetic prescribing information from Allergan, revised October 2024, carries the same warning in the other direction.

Until early 2024 I told readers that unit counts were the one number that travels between brands, and that comparing 20 against 20 was a fair shortcut for judging price. I stopped after reading the two glabellar sections side by side. The comparison collapses before it reaches price, because the two labels do not measure the same event.

Both products use 20 Units for glabellar lines, delivered as four Units into five sites, one in the procerus and two in each corrugator. From there the evidence diverges. Botox Cosmetic's glabellar program used co-primary endpoints at Day 30: the investigator scored a responder as reaching severity none or mild, and the subject scored a responder as reporting at least moderate improvement. Xeomin's composite demands a two-grade improvement from both raters. Reaching "mild" from a moderate baseline is a one-grade move. Reaching it from severe is two.

So Botox Cosmetic's 80% investigator responder rate at Day 30 and Xeomin's 60% and 48% composites are not a ranking. They are two different questions with two different passing scores.

Botox Cosmetic's tables report investigator responder rates of 74% at Day 7, 80% at Day 30, 70% at Day 60, 48% at Day 90, and 25% at Day 120, with subject-rated response at 39% by Day 120. Xeomin's label shows the equivalent by-visit data as a figure without printed values. Both programs followed subjects for 120 days. A published curve on one side and a silent figure on the other is a difference in reporting. It is not evidence that one product fades sooner.

Forehead, crow's feet, and the areas with no evidence at all

Horizontal forehead lines come with an instruction attached to the dose: treat the forehead in conjunction with the glabella, to reduce the chance of brow ptosis. Twenty Units go into five horizontally oriented sites in the frontalis, at least 2 cm above the orbital rim, for a combined maximum of 40 Units with the glabella. Lateral canthal lines take four Units into three sites per side, 12 per side, 24 total.

The forehead posted the highest Day 30 success of the three areas in both trials, at 67% and 58%. It also sits on the muscle that lifts the brow, which is why the label pairs it with the glabella and why an isolated forehead result can read as a heaviness rather than a smoothness.

I cannot tell you what 20 Units will do at your glabella. I have never injected anyone and hold no clinical follow-up on any patient. What I can vouch for is the distance between what a menu promises and what the printed directions say, because matching those two documents is the work I have done for years, first on a Seoul pharmacy floor and then across concern-led beauty shelves.

When a short result deserves review

Popular explanations for a short result usually run to metabolism, exercise, and smoking. None of those is quantified anywhere in the Xeomin label as a duration modifier.

Antibody resistance gets raised next, and here the label is unusually specific. Of 2,649 patients treated with Xeomin across its clinical trials, 9 (0.3%) tested positive for neutralizing antibodies after treatment with unknown baseline status, and 4 more (0.2%) developed them. No patient in that dataset showed a secondary loss of treatment response attributable to neutralizing antibodies.

The likelier variables are dose per area, placement, baseline severity, and which endpoint you were silently comparing yourself against. Side effects vary by indication too. In the upper facial lines trials, adverse reactions were reported in 11% of the 545 Xeomin-treated subjects against 8% on placebo, with injection site bruising at 2% and brow ptosis at 0.7%. The cervical dystonia trial reported dysphagia in 13% of the 120-Unit group and 18% at 240 Units, against 3% on placebo. Blepharospasm patients previously treated with onabotulinumtoxinA reported eyelid ptosis at 19%. The same molecule, the same label, three unrecognizably different risk profiles.

How to check whether your result was actually short

1. Write down the indication and the specific area treated.
2. Get the dose in Units per area from your chart, not the session total.
3. Note the date of onset and the date you first noticed the decline.
4. Compare both against the Day 30 assessment point and the retreatment floor for that indication.
5. Bring those four items to your injector before assuming an underdose.

Questions people actually ask

When does Xeomin start to wear off?

Xeomin's label reports a typical duration of up to 12 to 16 weeks per treatment. The decline is gradual. In the comparable Botox Cosmetic glabellar data, investigator-rated response fell from 80% at Day 30 to 48% at Day 90, so expect a partial return of movement well before month four.

Is 20 units of Xeomin enough?

Twenty Units is the maximum recommended dose for glabellar lines on the Xeomin label, delivered as four Units into each of five sites. It is also the dose used in the pivotal trials. Twenty Units spread across both the glabella and the forehead is a different regimen; the label allocates 20 to each area separately.

Does Xeomin wear off faster than Botox?

No labeled evidence supports that. Neither prescribing information reports a head-to-head duration endpoint, and their glabellar responder definitions differ, so their percentages cannot be ranked against each other. Both labels state that their potency Units cannot be converted into units of any other botulinum toxin product.

How long does Xeomin last in the forehead?

The label gives no separate forehead duration figure. It sets retreatment at no more frequently than every three months, instructs that forehead lines be treated together with glabellar lines at 20 Units, and reports Day 30 treatment success of 67% and 58% for the forehead area across the two upper facial lines trials.

How long does Xeomin take to take effect?

The prescribing information reports a median onset of treatment effect within two to seven days after injection. Trial outcomes were assessed at Day 30 for upper facial lines, at Week 4 for cervical dystonia, and at Week 6 for blepharospasm, so the visit that defines a documented result sits weeks past the first visible change.