How long does Botox last? Explaining duration data by treatment area with research papers

How long does Botox last? Explaining duration data by treatment area with research papers

"About 3 months, I guess"——you must already be unsatisfied with this answer you get at clinics.

That's because what you really want to know is the specific numbers: "For my treatment area, with my gender, using which product, how many weeks will it last?"

In fact, medical papers already have the answer. For the glabella, maximum 24.2 weeks. For the crow's feet, maximum 157 days. Around the mouth, when combined with hyaluronic acid, the duration extends by1.5 times or more——these are all data from peer-reviewed clinical research.

In this article, we explain the following 4 points using only research data.

• The basic mechanism of action of Botox (botulinum toxin) and the mechanism by which effects wear off
• Detailed effect duration by treatment area: glabella, crow's feet, forehead, perioral region, masseter (jawline), etc.
• How duration changes based on injection volume (units) and product type
• Differences in effect duration between genders

For those who cannot accept "it varies from person to person," we use only data from reliable medical papers and systematic reviews worldwide to thoroughly explain Botox duration by treatment area and product type.

Why does the effect wear off in the first place?——mechanism of action and duration mechanism

Without understanding this, you will never understand "why does my effect wear off faster than others."

When BontA is injected into muscle, the toxin diffuses into the nerve terminal and binds, preventing the release of the neurotransmitter acetylcholine. This inhibits action at the neuromuscular junction, resulting in muscle contraction ceasing and dynamic wrinkles (expression wrinkles) not forming (Berry 2012).

Complete absence of muscle activity occurs approximately 5 to 15 days after injection (Berry 2012). Since specific facial muscles stop contracting, you can notice a reduction in wrinkles (Fagien 2003).

So why does the effect wear off after several months?

The answer is simple——the nerve "regenerates." Chemical effects causing muscle atrophy trigger a regeneration process known as "sprouting" at the nerve terminal. This regeneration process lasts 120 days, creating new terminals at the neuromuscular junction and ultimately restoring muscle activity. Due to such mechanisms, clinical treatment effects typically last 3 to 6 months (Berry 2012).

Now that we understand the mechanism, let's look at specific numbers by treatment area.

【Glabella】The area with the most research data——17.6 weeks to 24.2 weeks

One of the most common treatment areas in aesthetic medicine (Cochrane Review 2021) is glabellar wrinkles. Therefore, data is most abundant.

First, let me break what you think is "common knowledge."

Is "high dose = longer lasting" really true? Comparison data from 20U to 80U

If you quadruple the dose, does the duration also quadruple?——unfortunately, it doesn't. The numbers speak for themselves.

• OnabotulinumtoxinA 20U(Carruthers 2005b): average duration 17.6 weeks
• Same product 40U(Carruthers 2005b): 21.7 weeks
• Same product 60U(Carruthers 2005a): 22.8 weeks
• Same product 80U(Carruthers 2005a): 24.2 weeks

Even when increasing dose 4-fold from 20U to 80U, duration only extends from 17.6 weeks to 24.2 weeks. In other words, higher doses do result in longer-lasting effects, but they don't dramatically double. "The more you inject, the longer it lasts" is not that simple.

Differences in glabellar duration by product type

Next, data by product. Botox exists in multiple formulations, each with reported duration data.

IncobotulinumtoxinA (XEOMIN®, etc.)Duration is 20.8 weeks (146.12 days) in women and 17.3 weeks (121.14 days) in men. OnabotulinumtoxinA duration in the same study was 20 weeks (140.65 days) in women and 16.6 weeks (Rappl 2013) (116.61 days) in men, with both products showing very similar durations.

AbobotulinumtoxinA (Dysport®, etc.)

• In a study compared to placebo, the median duration was 12 weeks(Brandt 2009) (85 days)
• In another study 15.3 weeks(Kane 2009) (107 days)
• In yet another study, the median effect duration was 117 days(Monheit 2019)

DaxibotulinumtoxinAWith a 60U injection, effect duration reached 22.5 to 23.2 weeks. With 20U of the same product, 20.8 weeks, and with 40U (Carruthers 2017), 22.80 weeks of prolonged duration was shown.

NewBontA (Prosigne®, etc.)NewBontA 20U duration was 12 weeks(84.5 ± 38.8 days), nearly equivalent to the compared OnabotulinumtoxinA 20U (Won 2013) of 12.8 weeks (89.9 ± 41.1 days).

【Forehead】Horizontal wrinkles last 113–125 days——dose difference is minimal

Forehead horizontal wrinkles are also a representative Botox treatment area. Like the glabella, higher doses result in longer duration, but the difference is limited.

When OnabotulinumtoxinA 40U was injected, physician-assessed treatment effect duration was 118.5 days, and patient-assessed duration was 125 days. In the group receiving 30U, physician assessment showed 113.0 days, patient assessment 115.5 days(Solish 2016).

The difference between 40U and 30U is only 5–10 days. The relationship between dose and duration here again shows "not a dramatic proportional relationship."

【Crow's feet】Laugh lines last maximum 157 days——Japanese data available

Wrinkles at the outer corners of the eyes when smiling, the so-called "laugh lines." Data for this area actually varies considerably between studies.

• OnabotulinumtoxinA 24U (Carruthers 2014): physician-assessed 16.8 weeks (118 days), patient assessment 16.5 weeks (116 days). In patients who showed at least 1 grade improvement from baseline, physician assessment showed 17.8 weeks (125 days), patient assessment 20.5 weeks (144 days)
• In another study, the duration of effect of OnabotulinumtoxinA 24U (Wu 2019) was approximately 150–157 days
• in Japanese subjectsIn a study of Japanese subjects, the duration of OnabotulinumtoxinA 24U (Harii 2017) was approximately 95 days(85 days at 12U)

The figure of approximately 95 days shown in Japanese data is shorter than overseas data of over 150 days. This may be influenced by differences in body size and muscle mass. Remember that you should reference data from the same race as your own data.

【Perioral】Alone 9.9 weeks——but when combined with hyaluronic acid, it extends to 15.5 weeks

Now, let me discuss a combination approach that many don't know about, which can make a real difference.

Perioral wrinkles have a slightly shorter duration compared to other areas——this is a fact. The average duration of effect when OnabotulinumtoxinA 9U alone (Carruthers 2010) was administered was 9.9 weeks(69.3 ± 11.0 days).

However, when the same 9U of OnabotulinumtoxinA was combined with hyaluronic acid (JUVEDERM ULTRA® etc.), the duration of effect was significantly extended to 15.5 weeks(108.9 ± 12 days) (Carruthers 2010).

9.9 weeks → 15.5 weeks. An extension of approximately 56%.

For deep perioral wrinkles, combination therapy of Botox (which suppresses muscle movement) and hyaluronic acid (which fills grooves) is extremely effective. If you are trying to treat perioral wrinkles with "Botox alone," it is worth asking your doctor about the possibility of combination treatment.

【Masseter (jaw muscle)】Repeated injections require caution——data shows function may not recover even after 6 months

Botox injections into the jawline (masseter) carry risks not present in other areas. If you are repeatedly receiving injections without knowing this, please do not skip reading.

Botox injections into the masseter (muscle hypertrophy) are extremely popular for slimming the face by sharpening facial contours and for treating teeth grinding and jaw clenching. However, injections into the masseter have precautions that differ from other treatment areas.

Single injection versus repeated injections——the serious difference data reveals

In a clinical trial of 26 women (Souza Nobre 2024), 75U (Souza Nobre 2024) of Abobotulinumtoxin was administered to each masseter. Single low-dose BontA injection is thought not to produce permanent effects on muscle thickness, and assessment by ultrasound imaging alsoshowed thickness beginning to recover after 3 months (Souza Nobre 2024)has been confirmed.

This is where it gets important.

In the group that received an additional booster injection 3 months after the first injection (Souza Nobre 2024), even after 3 months had passed since the second injection (a total of 6 months from the first injection),muscle thickness did not return to normal(Souza Nobre 2024). It has been pointed out that this may be the result of incomplete recovery of nerve innervation or progressive atrophy of muscle fibers.

Long-term effects on chewing function—"Biting force" does not return to normal for more than six months

Bite force (chewing power) also returns to normal gradually in 3 months (Souza Nobre 2024) with a single injection3 months (Souza Nobre 2024) for bite force (chewing power) to gradually return to normalHowever, when additional injections were performed after 3 months,muscle activity had not recovered even at the 6-month follow-up assessment(Souza Nobre 2024). Additionally, regarding chewing performance (mastication ability), in both the single injection and the additional injection at 3 months,function remained impaired throughout the 6-month follow-up period(Souza Nobre 2024).

When botulinum toxin is repeatedly injected into the masseter muscle for cosmetic purposes only, functional adverse effects such as muscle atrophy and decreased chewing function may persist for extended periods; therefore, careful attention to treatment intervals is necessary.

Another factor influencing duration—"sex" causes approximately a 25-day difference

Duration of effect is not determined by treatment area and product alone. Whether you are male or female also significantly affects how long the results last.

Generally, men have more developed muscles and greater muscular strength than women. This fact can directly impact the number of Botox units needed to treat wrinkles and the duration of effect (Cochrane Review 2021).

Looking at the numbers, the difference is striking.

In the group administered IncobotulinumtoxinA, the duration of treatment effect was146.12 days in womenwhereas in men it was121.14 days—approximately 25 days shorter. Similarly, in the group administered OnabotulinumtoxinA,women's duration was 140.65 dayswhereas in men it wasmen was 116.61 days(Rappl 2013).

Men who have felt "why does it seem to wear off faster for me?"—that is not just a feeling; it is backed by published data. In men's cases, higher-than-standard doses or treatments at shorter intervals may be necessary.

Summary: Duration of Effect by Treatment Area—Data Table

Now that you've read this far, you no longer need to be confused by vague phrases like "it varies from person to person." Let us organize the facts shown by published data one final time.

• Glabellar lines (between the eyebrows): Duration varies by dose, but generally lasts approximately 17 weeks (Carruthers 2005a) to 24 weeks (Carruthers 2005a). With high doses (80U), it lasts 24.2 weeks, but the duration does not scale perfectly with dose.
• Crow's feet (lateral eye wrinkles): Generally lasts approximately 16 weeks (116–118 days) to 20 weeks (approximately 144 days) (Carruthers 2014).
• Forehead wrinkles: With doses of 30U to 40U, duration is approximately 113–125 days (Solish 2016).
• Perioral wrinkles: Botox alone provides relatively short duration of 9.9 weeks, but when combined with hyaluronic acid, duration extends to 15.5 weeks (Carruthers 2010)—approximately 56% longer.
• Jawline (masseter muscle): Single injection shows recovery beginning in approximately 3 months, but repeated injections at short intervals risk adverse effects such as muscle atrophy and reduced chewing function lasting 6 months or longer (Souza Nobre 2024).
• Gender effect: Men, due to stronger muscular force, tend to experience approximately 25 days shorter duration of Botox effect compared to women (Rappl 2013).

Botox is a safe and effective treatment method. By understanding its mechanism of action, the characteristics of different treatment areas, and your own muscular strength (such as gender), you can develop a treatment plan with higher patient satisfaction. At your next clinic visit, consider referencing this data and discussing appropriate dosage and treatment schedule with your doctor.

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References

1. Gostimir M et al. Safety of Botulinum Toxin A Injections for Facial Rejuvenation: A Meta-Analysis of 9,669 Patients. Ophthalmic Plast Reconstr Surg. 2023
2. Carruthers J, Carruthers A. Botulinum toxin type A treatment of multiple upper facial sites: patient-reported outcomes. Dermatol Surg. 2007
3. Carruthers J et al. Injectable daxibotulinumtoxinA for glabellar lines. Dermatol Surg. 2017

Author of this article

Hiromitsu NakamuraPhysician, Ginza Clinic

Zetith Beauty Clinic Ginza Clinic, Osaka Shinsaibashi Clinic, Fukuoka Clinic

With experience presenting research at domestic and international academic conferences, he is involved in technical guidance and education across all Zetith Beauty Clinic locations. Specializing in precise aesthetic medicine based on anatomical principles, he pursues natural results tailored to each individual's bone structure and tissue composition.