How Long Does Botox Last? What the Trial Data Actually Shows
Reviewed for medical accuracy against our Medical Review Board · Last updated 26 August 2026
Part of Botox Guides: Basics, Dosing and Safety
The label says the effect on frown lines lasts approximately three to four months, and that is the honest headline. The trial data underneath it is more useful: 80 percent of people met the response threshold at day 30, 70 percent at day 60, 48 percent at day 90 and 25 percent at day 120. So at the three month mark, when most people book their next appointment, fewer than half were still responding.
That is not a criticism of the drug. It is the difference between "when does it stop working" and "when does it stop being measurable", and the gap between those two is where most of the confusion about Botox duration lives.
1. The decay curve, day by day
The two pivotal glabellar line studies enrolled 405 people on BOTOX Cosmetic and 132 on placebo, each receiving a single 20 unit treatment across five sites. A responder was someone the investigator graded as having no or only mild lines at maximum frown. Here is what happened over the following four months:
| Day | BOTOX Cosmetic | Placebo | Difference |
|---|---|---|---|
| 7 | 74% (299/405) | 6% (8/132) | 68 points |
| 30 | 80% (325/405) | 3% (4/132) | 77 points |
| 60 | 70% (283/403) | 2% (2/130) | 69 points |
| 90 | 48% (192/403) | 2% (3/128) | 45 points |
| 120 | 25% (102/403) | 2% (2/128) | 24 points |
Read day 90 and day 120 together. The label's "approximately 3 to 4 months" is not wrong, but it describes the outer edge rather than the middle. At three months less than half the trial population still met the threshold, and at four months a quarter did. If you feel your Botox is already fading at ten or eleven weeks, you are not unusual and you have not been underdosed. You are the majority.
Notice also how flat the placebo column is: 6%, 3%, 2%, 2%, 2%. Unlike some of the injectable trials on this site, there is almost no placebo effect to subtract here. Whatever you are seeing at day 30 is the drug.
2. You will rate it higher than your injector does
The same trials asked the subjects themselves, using a different question: had their glabellar lines improved at least moderately?
| Day | You (at least moderate improvement) | Your injector (none or mild lines) |
|---|---|---|
| 7 | 82% | 74% |
| 30 | 89% | 80% |
| 60 | 82% | 70% |
| 90 | 63% | 48% |
| 120 | 39% | 25% |
Patients are consistently more positive, and the gap widens as the effect fades: 9 points at day 30, 15 at day 90, 14 at day 120. Be careful what you conclude from that. The investigator was asked whether the lines are objectively gone; you were asked whether things improved. Those are not the same bar, so this is not evidence that patients are fooling themselves. What it does mean is that a clinic quoting patient satisfaction figures and a clinic quoting clinical response rates are quoting different things, and the patient number will always look better.
3. When it starts, which is not the same question
From the label: chemical denervation of the injected muscle begins one to two days after injection and increases in intensity during the first week. That matches the trial data, where 74 percent were already responders at day 7.
So the useful mental model is not a plateau. It is a ramp of about a week, a peak somewhere in the first month, a long slow decline through months two and three, and very little left by month four. Judging your result before day 14 is judging it on the way up. Our main Botox guide covers the full timeline.
4. Age changes the answer more than anything else
Buried in the same label is a split by age at day 30 that changes the picture considerably:
| Age | Investigator assessment | Subject assessment |
|---|---|---|
| Under 65 | 83% (316/382) | 91% (346/382) |
| 65 and over | 39% (9/23) | 70% (16/23) |
That is a very large difference, and it needs a caveat stated as plainly as the number itself: only 23 subjects were 65 or over, against 382 under 65. Nine responders out of 23 is a fragile figure, and the confidence interval the label reports for that group runs from minus 17 to plus 51, which means it does not exclude zero. Treat it as a signal worth knowing rather than a settled fact.
The mechanism is not mysterious, though. Toxin relaxes muscle. It does not fill a crease that has become a permanent fold in the skin, and the older the line the more of it is skin rather than movement. The label also notes that responder rates were higher for women than for men.
5. Why each area seems to give a different answer
Search for how long Botox lasts and you will find wildly different numbers by area. Much of that is not biology, it is which question the trial asked:
| Area | Day 30 response | What counted as success |
|---|---|---|
| Frown lines | 80% | Graded none or mild |
| Forehead lines | 61% and 46 to 53% | At least a 2-grade improvement |
| Crow's feet | 26.1% and 20.3% | At least a 2-grade improvement |
| Platysma bands | 32% at day 14 | Grade 1 or 2 and a 2-grade improvement, both assessors agreeing |
Crow's feet at 26.1 percent looks like a failure next to frown lines at 80 percent. It is not. The crow's feet trial required a two grade improvement on a composite of investigator and subject assessment, which is a far harder bar than "the lines are now mild". Anyone comparing those two figures without saying so is comparing a high jump with a hurdle.
6. The three month rule, and where it comes from
The label is explicit:
The safety and effectiveness of dosing with BOTOX Cosmetic more frequently than every 3 months have not been clinically evaluated.
That is not a finding of harm. It is an absence of study. But it explains why a reputable clinic will decline to retreat you at eight weeks even when you can see the effect fading, and it is worth knowing that the reason is regulatory caution rather than an arbitrary policy. In the forehead studies, subjects received three cycles over one year, which works out at the same interval.
7. What actually makes it last longer
- Dose, within reason. An underdosed area fades sooner because there was less to lose. This is the most common reason a result feels short. See the units guide for the labelled figures by area.
- Which area. Large strong muscles such as the masseter hold a result longer than the delicate orbicularis around the eye, which is thin, constantly moving and close to the surface.
- Consistency over time. Regular treatment tends to mean the muscle is never back to full strength when the next dose arrives, so people often report needing less over the years.
- Not aftercare. This is the honest part. The rules about exercise, heat and lying down do not appear anywhere in the label, as covered in the aftercare guide. Following them is cheap and sensible; expecting them to extend your result by weeks is not supported.
8. How the other toxins compare
Each product's label states its own duration and they are not interchangeable claims. Ours are covered separately: how long Dysport lasts, where the label offers up to four months and says nothing at all about onset, and how long Xeomin lasts, where the label gives a median onset of two to seven days and a duration of up to 12 to 16 weeks, which is the most specific of the three.
Daxxify is the outlier, marketed on a longer duration than the others. Whether the extra weeks are worth the price difference is a cost question rather than a duration one, and our price guide has the arithmetic.
Frequently asked questions
How long does Botox last?
Why did my Botox wear off after 2 months?
Does Botox last longer the more you do it?
How soon does Botox start working?
Can I get Botox again after 2 months?
Does Botox work less well if you are older?
Does exercise make Botox wear off faster?
Which area does Botox last longest in?
Know the count before the quote. The unit count is half the bill, and a low per-unit rate recovered by a high unit count is the commonest way a deal is not one. How to tell.
Deciding which area, not how many units? Botox by facial area covers what each zone actually achieves, which four are FDA approved, and the things Botox cannot fix at all.
