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 16

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
4.5 out of 5 stars 4 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, 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
4.6 out of 5 stars 24 reviews

How long does Botox last in the Masseter

Fortunately, Botox will on average wear off in 3-4 months, so this is not a permanent procedure.  Unfortunately, it takes on average 3-4 months to wear off.  It doesn't matter where in the face the Botox was injected, the injection itself will wear off in the same amount of time. 

Ben Brown, MD
Pensacola Plastic Surgeon
5.0 out of 5 stars 58 reviews

Botox for masseter hypertrophy

The masseter muscle is one of the muscles activated during chewing. It’s located at the “angle of the mandible”, or “angle of the jaw”. Masseter muscle hypertrophy is enlargement of the masseter muscle, and can contribute to a harsh, square look at the angle of the jaw. Botox can be used to relax this muscle, and to soften the look of the lower face. I usually start with 50 units of botox (25 units on each side). When Botox is used to relax the facial muscles that cause fine line, the maximum effect is seen in 7-10 days. When Botox is used to reduce masseter muscle hypertrophy, the maximum effect is not seen for 3 months. Results can last up to 9 months. I recommend repeat injection every 6 months if you would like to maintain your results. 

Dara Liotta, MD
New York Facial Plastic Surgeon
4.9 out of 5 stars 30 reviews

How long will Botox last?

You should expect to see results in three to four days, but in as few as two and as many as five days. On average patients return every three to six months for additional treatments. Good luck.

Richard Zienowicz, MD
Providence Plastic Surgeon
4.9 out of 5 stars 56 reviews

Botox in Masseter muscle NYC

Botox will last about 4 months in the area. However if you have a strong muscle and grind your teeth you will need more frequent treatments to shrink the masseter muscle. Please consult an expert. Best, Dr. Green

Michele S. Green, MD
New York Dermatologist
5.0 out of 5 stars 71 reviews

Duration of Botox in the masseter muscles

Thanks for the question. This is one of my favorite uses of Botox, as I've been able to help hundreds of patients overcome their severe TMJ pain and teeth grinding. Additionally, many female patients receive masseter Botox to narrow the jawline, creating a thinner look to the lower face. In general, the Botox begins to wear off around 3-4 months later, but many patients don't feel the need for another treatment until 6-12 months post-treatment. This is because the muscles remain a bit smaller and softer, and many patients are able to break the habit of grinding their teeth. If patients return on the earlier side, I can often achieve the same results with fewer units. 

Best regards,
Dr. Mehta

Umang Mehta, MD
Bay Area Facial Plastic Surgeon
4.6 out of 5 stars 45 reviews

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.  

Melissa Chiang, MD, FAAD
Houston Dermatologic Surgeon
5.0 out of 5 stars 12 reviews

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 12 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.