How Long Does Botox Last? Duration Data by Facial Area Explained in Medical Literature

Introduction

The month after your first Botox injection, have you ever looked in the mirror and thought, "Wait, is the effect already fading?"

In fact, that feeling is not just in your head. Depending on the area treated,65 days—medical literature shows data indicating that the effect can be cut in half.

So which areas hold results longer? Will increasing the dose solve the problem? Is there a difference between men and women?

What this article will clarify:

• The medical mechanism behind Botox wearing off and the neural regeneration process
• Precise duration of effect by facial area—between the eyebrows, crow's feet, forehead, around the mouth, and more
• Differences in duration based on injection volume (units) and Botox type (brand formulation)
• Duration of injections for the masseter muscle (jaw bulging) and functional risks associated with repeated treatment
• Differences in Botox efficacy between men and women

Rather than relying on personal impression or clinic marketing claims, this article provides an in-depth, area-by-area explanation based solely on rigorous clinical trial data published in peer-reviewed literature. By the time you finish reading, you should have a clear picture of what to choose and how at your next injection appointment.

1. Botox (BontA) Basics: Why Does the Effect Fade?

First, you need to know this: Botox does not last forever—But that is not a bug; it is a feature.

Once you understand the mechanism behind how the effect wears off, you will realize it is actually a "sign of safety." In aesthetic medicine, botulinum toxin type A (BontA) injection for dynamic wrinkles (expression lines) is the most common treatment. According to statistics from the American Society of Plastic Surgeons, in 2016 alone,4,597,886 injectionswere performed (ASAPS 2016). Additionally, the average cost per Botox treatment session is reported to be385 US dollars—making it a procedure that millions of people worldwide undergo (ASAPS 2017).

The reason BontA has become so widely adopted is that compared to surgical procedures, the cost is low, there is no downtime, and most importantly, "the effect is temporary" (Glogau 2012). Because the effect does not last forever, there is reassurance that even if you are unhappy with the result, it will eventually return to normal.

So why is the effect temporary?

When injected into muscle, botulinum toxin diffuses and binds at the nerve ending, blocking the release of the neurotransmitter "acetylcholine" from the nerve synapse. This prevents the muscle from contracting, so the skin does not form wrinkles. Complete muscle paralysis occursapproximately 5 to 15 daysafter injection (Berry 2012).

However—the human body is remarkably sophisticated, and this is where the real story begins.

In place of the nonfunctional nerve ending, the body initiates a neural regeneration process called "sprouting." This sprouting process continues forapproximately 120 daysand forms new nerve endings at the neuromuscular junction, allowing the muscle to regain its activity (Berry 2012). Therefore, the duration of clinical therapeutic effect is reported to fall within a range of3 to 6 months (approximately 90 to 180 days)on average (Glogau 2012; Berry 2012).

In other words, the moment you feel the effect wearing off is proof that your body is functioning normally. Now let us look at the duration by treatment area based on the numbers from the literature.

2. [By Facial Area] Duration of Botox as Shown in Medical Literature: Between the Eyebrows

Average of 99.7 days.This is the figure produced by a large-scale systematic review as the duration of Botox effect for glabellar lines (frown lines between the eyebrows).

Glabellar lines are the most extensively analyzed area in Botox treatment research, and abundant data exist on this region. Derived from randomized controlled trials (RCTs), this value varies significantly depending on injection volume, formulation, and ethnicity.

For example, look at data from Japanese patients. In a study of Japanese patients, the average effect duration for OnabotulinumtoxinA (Botox from Allergan) at 20 units (U) was9.4 weeks (approximately 65 days), and at 10U it was7.9 weeks (approximately 55 days)(Harii 2008). Even at the standard dose of 20U, the effect begins to diminish after about 2+ months.

However, the picture changes in research primarily from North America. According to a dose-comparison study using OnabotulinumtoxinA, the duration of effect for glabellar lines is as follows (Carruthers 2005a; Carruthers 2005b):

• 20U group:17.6 weeks (approximately 123 days)
• 40U group:21.7 weeks (approximately 151 days)
• 60U group:22.8 weeks (approximately 159 days)
• 80U group:24.2 weeks (approximately 169 days)

The numbers speak for themselves. The higher the dose, the longer the duration.

Furthermore, in research by Solish et al., the duration of OnabotulinumtoxinA 30U for glabellar and forehead wrinkles was16 weeks (113.0 days)by physician assessment and16.5 weeks (115.5 days)by patient assessment; at 40U, physician assessment showed16.9 weeks (118.5 days)、patient assessment17.8 weeks (125 days)was (Solish 2016).

"If you increase the dose, it lasts longer" — this is true for the glabella. However, the risks of increasing the dose are explained in detail in a later section.

3. 【By Treatment Area】Botox Duration Data from Research: Crow's Feet Lines

Crow's feet lines — how do they compare to the glabella? The answer may surprise you.

The periocular area has thin skin, and muscle movement directly manifests as wrinkles. Intuitively, one might think "the effect appears less readily and wears off quickly." However —

In a Japanese patient RCT, the duration of effect in the group receiving a total of 12U of OnabotulinumtoxinA injected on both sides of the eyes was85 days、in the group receiving a total of 24U was95 days（Harii 2017）. As with the glabella, a trend was confirmed showing longer duration with higher doses.

But here comes surprising data.

In another study, when OnabotulinumtoxinA 24U was injected at the crow's feet, the duration was reported asapproximately 150–157 daysby both physician and patient assessment （Wu 2019）. Furthermore, in a multi-center collaborative study, the duration (median) was16.8 weeks (118 days)by physician assessment and16.5 weeks (116 days)by patient assessment, with some conditions reaching a maximum of20.5 weeks (144 days)（Carruthers 2014）.

The crow's feet area is a site where the effect may last as long as, or even longer than, the glabella. The assumption that "crow's feet wear off quickly" is contradicted by the data.

4. 【By Treatment Area】Botox Duration Data from Research: Perioral Lines and the Remarkable Synergistic Effect of Hyaluronic Acid

Fine vertical lines around the mouth （Perioral lines） — this is the site with the shortest duration. And there is a method to dramatically change that.

The perioral area moves frequently with eating and speaking. In one study, the duration when OnabotulinumtoxinA 9U was injected was an average of9.9 weeks (69.3±11.0 days)（Carruthers 2010）. Clearly shorter compared to the glabella and crow's feet.

I would like to pose one question — if you're paying the same amount, wouldn't you want it to last as long as possible?

In the group using the same 9U of Botox combined with hyaluronic acid (24-mg/mL cohesive gel), the average duration was extended to15.2 weeks (106.6±10.6 days)（Carruthers 2010）.

The comparison in numbers is striking:

• Botox alone:approximately 70 days
• Botox + hyaluronic acid:approximately 107 days

With the same Botox dose, simply adding hyaluronic acid extends the duration byapproximately 1.5x**. For frequently moving areas like the perioral region, combination with fillers is the key factor for controlling the effect duration.

5. Does the Type (Formulation) of Botox Affect Duration?

Does choosing a particular brand change the duration? In short, conventional formulations show little difference — but next-generation types are a different story.

Currently, multiple botulinum toxin type A (BontA) products exist in the aesthetic medicine market. Major ones approved by the FDA, EMA, and others include Botox (OnabotulinumtoxinA), Dysport (AbobotulinumtoxinA), Xeomin (IncobotulinumtoxinA), and the newer DaxibotulinumtoxinA. All are type A toxins, but differ in bacterial strain and biological properties (potency equivalence, diffusion in the dermis, etc.) （Glogau 2012）.

In a study of AbobotulinumtoxinA (Dysport) 50U injected into the glabella, the median duration was reported as12 weeks (85 days)（Brandt 2009） to15.3 weeks (107 days)（Kane 2009）, or117 days（Monheit 2019）.

In a direct comparison of three formulations, in women （Rappl 2013）:

• IncobotulinumtoxinA:20.8 weeks (146.12 days)
• OnabotulinumtoxinA:20 weeks (140.65 days)
• AbobotulinumtoxinA:139.69 days

The differences are merely a few days. Among the three conventional formulations, there is no dramatic difference in duration.

However — next-generation types have arrived.

In studies using DaxibotulinumtoxinA, in which peptide technology was employed to extend the effect, the effect duration of 60U was23.2 weeks (approximately 162 days)compared with placebo at 0.4 weeks, showing an overwhelming difference (Carruthers 2017). Furthermore, in a large-scale pooled data analysis of 40U,24 weeks (approximately 168 days)responder rates were significantly higher compared to placebo (Bertucci 2020).

For patients who want "results to last as long as possible," the choice of formulation will become an increasingly important option going forward.

6. Does increasing the dose (units) make results last longer?

Answer: To some extent, yes. However, there is an upper limit.

Many patients ask: "If I increase the units, will the results last longer?" Based on the published data, a certain degree of dose increase does reliably contribute to extending the duration of effect.

As demonstrated in the Carruthers et al. study mentioned earlier (Carruthers 2005a; Carruthers 2005b), when increasing the dose of OnabotulinumtoxinA to the glabella:

• 20U →17.6 weeks
• 40U →21.7 weeks
• 60U →22.8 weeks
• 80U →24.2 weeks

At the lateral canthus, doses of 12U85 dayswere extended to 24U95 dayswith increased duration (Harii 2017).

However, the question of whether "more is always better"—the answer is no.

Excessive units carry significantly increased risk of adverse effects such asptosis(drooping eyelids) and "Spock brow," where facial expressions freeze completely and appear unnatural. There is always a trade-off between increasing dosage and safety. Careful assessment and balance adjustment by the physician—tailored to each patient's individual muscle strength and facial expression patterns—is essential.

7. Does Botox work differently in men vs. women?

Even at the same dose,men experience results wearing off approximately 3–4 weeks earlier than women.This is the conclusion from published data.

Generally, men have stronger development of facial muscles (mimetic muscles) and greater muscle mass than women. This anatomical fact directly influences the duration of effect.

In research that actually measured the duration of effect by gender (Rappl 2013), consistent results appeared across all formulations:

• IncobotulinumtoxinA: women20.8 weeks (146.12 days)vs men17.3 weeks (121.14 days)
• OnabotulinumtoxinA: women20 weeks (140.65 days)vs men16.6 weeks (116.61 days)
• AbobotulinumtoxinA: women139.69 daysvs men115.81 days

Regardless of formulation, there is a clear trend that results wear off approximately 25 days earlier in men.

This means that for men to achieve effects and duration comparable to women, a higher number of units than the standard dose may be necessary. During clinic consultations, verifying whether the dose is being set with consideration to gender and muscle strength is an important factor in making results last longer.

8. Effects and duration on jaw muscles (masseter hypertrophy): the beauty-function dilemma

Botox to the jaw muscles carries risks fundamentally different from those of facial wrinkles. Continuing treatment without understanding this is dangerous.

Botox injection to the masseter muscle is frequently performed for lower face contouring (reducing jaw flare and creating a slimmer face appearance) and to alleviate bruxism (teeth grinding and clenching). However, injection into this powerful muscle responsible for chewing shows a completely different response than thin mimetic muscles.

In a recent randomized triple-blind trial in women with masseter hypertrophy (MH) given a high dose of AbobotulinumtoxinA of 75U bilaterally (total150U), patient-reported jaw flare improved significantly1 monthafter injection. Although temporary reduction in chewing ability was observed, the muscle thickness itself began to recover3 months later(Nobre 2024). Another study showed that following a single 30U injection of OnabotulinumtoxinA, bite force and muscle activity gradually returned to normal over3 months(De la Torre Canales 2020). Additionally, a long-term follow-up study over4 yearsin Asian patients demonstrated that with regular injections, an average12%reduction in muscle volume was confirmed (Shome 2019).

However, look at the adverse event data.

In studies where AbobotulinumtoxinA (standard dose 140.62–187.5U) was injected into the masseter, patients experienced some form of adverse effect at a rate of18.8%(Ozdemir Cetinkaya 2024):

• Smile asymmetry:2.5%
• Paradoxical bulging:2.5%
• Pain at injection site and headache:3.8%

Furthermore, in patients with strong muscles, a single injection is insufficient, and 8.8%of patients required additional touch-up injections 10 days later (Ozdemir Cetinkaya 2024). It is important to know that in masseteric treatments, approximately 1 in 10 cases do not resolve with a single injection.

9. What happens with repeated injections over time? (Benefits and drawbacks of repeated administration)

Is it true that 'repeated injections build tolerance and stop working'? The answer is opposite depending on the treatment area.

Repeated administration for facial wrinkles: Significant benefits

In patients who received regular multiple injections of OnabotulinumtoxinA, the responder rate (proportion of patients showing results) at days 30, 60, 90, and 120 was significantly higher in the 3rd cycle (3rd injection) compared to the 1st cycle (1st injection) and 2nd cycle (2nd injection). The frequency of adverse events also decreases with repeated injections:

• 1st cycle:21.2%
• 2nd cycle:4.7%
• Cycle 3:2.0%

In wrinkle treatment, by continuing injections at appropriate intervals, the habit of excessive muscle movement is eliminated, allowing for sustained high efficacy with fewer side effects.

However——when it comes to the masseter muscle, the results are completely opposite.

Repeated injections into the masseter: serious risks

In a study by Nobre et al. (Nobre 2024), following the initial injection,3 months laterin the group that received Botox (booster injection) again,even at the 6-month follow-up pointMasseter thickness and muscle activity measured by electromyography (EMG) showed no recovery whatsoever. In both animal experiments and human studies, this is attributed to incomplete reinnervation of the nerve, fatty infiltration into the muscle, necrosis of muscle fibers, and fibrosis (hardening of the muscle)—resulting inpermanent atrophystrongly suggests the possibility of.

Repeated injections at short intervals that impair the function of the masseter muscle — which is essential for eating — solely for the purpose of achieving a slimmer face: you need to make a decision after understanding this risk.

Summary of this article

• The effects of Botox do not last permanently due to the nerve regeneration (sprouting) process, and on averageapproximately 4–6 months (120–180 days)disappears (Glogau 2012; Berry 2012).
• The duration for glabellar wrinkles is approximately 14 weeks (99.7 days) on average, but data shows that by increasing the dosage, the effect can be extended to24 weeks (approximately 6 months)(Carruthers 2005a).
• The effect on crow's feet tends to last relatively long, and some studies confirm duration ofapproximately 150 days or more (approximately 5 months)(Wu 2019).
• For perioral wrinkles, combined use with hyaluronic acid (approximately 3.5 months) produces dramatically longer-lasting results than Botox alone (approximately 2.5 months) (Carruthers 2010).
• Because men have more strongly developed muscles, the effects of Botox tend to wear offapproximately 3–4 weeks earliercompared to women. Dosage adjustment is necessary for men (Rappl 2013).
• DaxibotulinumtoxinA, the next-generation Botox, demonstrates significantly longer duration of approximately24 weeks (168 days)compared to conventional formulations (Bertucci 2020).
• Treatment of the masseter muscle requires caution: while a single injection results in muscle strength recovery in approximately 3 months, repeated injections at short intervals carry serious functional risks, including permanent muscle atrophy and impaired chewing function (Nobre 2024).

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References

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2. Rho N, Youn C, Youn S, et al. A comparison of the safety, efficacy, and longevity of two different hyaluronic acid fillers in filler rhinoplasty: A multicenter study. Dermatologic Therapy. 2021DOI
3. Kang G, Hsiao Y, Huang J, et al. Aesthetic Durable Forehead Contouring in Asians With Fat Grafting and Botulinum Toxin. Annals of Plastic Surgery. 2019DOI
4. E., R.A., R.M.. Journal of Cosmetic Dermatology. 2015
5. Bellamy J, Rohrich R. Superiority of the Septal Extension Graft over the Columellar Strut Graft in Primary Rhinoplasty: Improved Long-Term Tip Stability. Plastic & Reconstructive Surgery. 2023DOI

Author of this article

Hiromitsu NakamuraPhysician, Ginza Clinic

Zetith Beauty Clinic Ginza, Osaka, and Fukuoka branches

With a track record of presenting research at domestic and international conferences, he is involved in technical guidance and education across all Zetith Beauty Clinic locations. He specializes in precision aesthetic medicine based on anatomical foundations, pursuing natural results tailored to each individual's skeletal structure and tissues.