How Long Does Botox in the Masseter Muscle/jawline Really Last?

I only had 15 units per side 4 wks ago & it "worked" far too well! My doc says it'll wear off in 3-6 months, many Realself docs have stated 4-6, but I've heard reports that botox for jaw reshaping lasts way longer than in the forehead, i.e. 9-12 months! Some even say it's permanent (!!!) Going by averages, how long will it be before jaw botox actually begins to expire, and from there, when can one expect to be back to their pre-botoxed state - if ever!? :S

Doctor Answers 11

Botox in the masseter area

How long botox treatments "last" in the masseter depends on a number of factors.  One factor is if you are using a guard in your mouth to prevent grinding or clenching.  The guards prevent the muscles from working very hard, so the muscles do not regain their former strength.  I personally have had 50 units in each masseter for clenching, and wear a guard, and the muscle is reduced and soft over 9 months later.

If you are not using a guard, and did the Botox more for cosmetic treatment in the jawline area, nothing stops your muscles from gaining strength back, and the duration of action will likely be less than 6 months.  15 units is a very small amount if you had a thick masseter muscle.  I would bet you'll start to see increased thickness about 3-4 months after treatment without the mouth guard.

Hope that helps!

Madeline Krauss, M.D.


Boston Dermatologic Surgeon
3.0 out of 5 stars 1 review

Botox, Wrinkle Treatment, Beverly Hills Botox, Los Angeles Botox

 Because you're using the Botox in a larger muscle (the Masseter), which continues to contract everytime you chew or open/close the mouth...the effects of the Botox may not last as long as when it's injected into the forehead where you can go without using the muscles.  I like to do a full dose booster Botox treatment 1 month after the initial Botox treatment as a way to further weaken the targeted muscle(s). 

For the Masseter, I typically use an increased Botox dose, have the patient return in 1 month for a booster Botox treatment and then continue treatments at 4-6 month intervals until the desired effect is achieved.  Remember, the larger the Masseter, the more Botox is required to significantly weaken it.

Francis R. Palmer, III, MD
Beverly Hills Facial Plastic Surgeon
4.5 out of 5 stars 17 reviews

Botox Effect on Masseter Muscle Depends on Dose Given

As stated above, the longevity of the effect of Masseter muscle weakness after Botox injections, depends on a number of factors, the most important of which is the dose administered.  Typically, for lower face shaping, we use up to 30 units per side, which is twice what you received.  The effect generally lasts for 9-12 months.  In your case, I would expect return of masseter strength and thickness within 6 months.  If you are interested in reversing the effect of Botox in ANY anatomic area, one way to hasten this is to USE the muscles involved.  The Botox effect appears to wear off faster, the more the muscle is used.  In the case of Masseter muscles, you can do an "exercise" in which you clamp down your teeth hard, 10 times in a row, several times during the day, to more quickly reverse the Botox effect.

Sheldon Pollack, MD, FRCPC

Medical Director, Toronto Cosmetic Skin Surgery Centre, Inc.

Sheldon Pollack, MD
Toronto Dermatologic Surgeon
5.0 out of 5 stars 1 review

Botox in masseter lasts 3-6 months, depending on dose

The good news is that botox always wears away.  The stronger the dose, the longer it lasts.  In my patients, botox lasts from 3-6 months in the masseter area.

You will notice that your ability to clench your teeth returns first, and then the masseter will grow back again.  If this is your first treatment, your face should return fully to its original shape.  

4-6 months

There was a good study out of Asia looking at this and yes it does tend to last longer than in the facial muscles but probably no longer than 6 months.  Certainly not permanent.  The more times you do it, the more the muscles atrophy and yes, in that same study, if you did it for 5 years the muscles would permanently stay smaller but again, this is only after repeated treatments with no breaks over many years. 

Garrett Griffin, MD
Minneapolis Facial Plastic Surgeon
5.0 out of 5 stars 11 reviews

Botox masseter injections duration

I would say that the treatment lasts a couple months longer than the forehead/crows feet/frown regions.  It is also a gradual onset of the return of masseter function.  I have tried the masseter injections myself and space the treatments around 4 months apart, but use smaller doses to maintain the effect.  I normally know the effects are wearing down when I start to clench my teeth more heavily at night when asleep.

Depends on your body

The masseter muscle reacts to Botox in pretty much in the same way as any other muscle. Results last a few months but can last for up to a year depending on lifestyle habits. Touch-up injections may be required twice a year to maintain results.

Botox should wear off in 4 months

On average, the botox effect will wear off in four months. it will not be permanent. jaw shaping and masseter muscle will not be permanently affected by botox injections.

Ronald Shelton, MD
Manhattan Dermatologic Surgeon
5.0 out of 5 stars 37 reviews

Duration of Botox in the Jaw Muscle

Fortunately, you had a fairly low dose of Botox so it is likely to wear off in 3 to 6 months. There are many factors that can affect Botox uptake including hypertrophic muscles, muscle size, amount of nerve innervation, nerve stimulation, muscle activity and metabolism. Additionally it is interesting to note that in marathon runners and individuals that exercise more than 4 days a week, the duration of effect is slightly but noticeably less. Therefore it would be advisable for you to try to exercise these muscles as much as possible on a daily basis over the next few weeks to speed up the recovery process.

Mitchell Schwartz, MD
South Burlington Dermatologic Surgeon
5.0 out of 5 stars 10 reviews

Yes, yes, yes, it will wear off.

Generally even with this small dose, it will take 4-6 months for the massetter muscle volume to return to normal.  In terms of bit strength, this will begin to return to normal after a few months.  Hang in there.

Kenneth D. Steinsapir, MD
Los Angeles Oculoplastic Surgeon
5.0 out of 5 stars 22 reviews

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.