What is the Correct Way to Inject Botox for Jaw/masseter Contouring?

I use a 1/2" needle for treating wrinkles along the forehead, Crow's feet and glabella.  The masseter is a far bulkier muscle than the muscles in those areas, so as you can imagine the needle must deliver the Botox deeper in order to achieve the optimal effect.  I use a 1" needle for masseter injections and inject within the body of the muscle just above the bone.  The muscle is covered with a dense fascial layer, so if the injections are placed superficial to this any diffusion of the Botox will be limited by this layer.  The needle must penetrate this fascia and deliver the Botox within the body of the muscle.  

Especially with 20 units per side, additional units may need to administered to achieve maximal effect.  This is common for an initial treatment, and your physician will be able to titrate the appropriate dosage better with future treatments based on your response to this initial treatment.  

I think you're main concern is that you don't see results in 2 weeks.  I think the sequence is the following:1) botox injection (20 units per side is an okay starting point)2) within 2 weeks, you should feel that your muscles can't clench down as hard (you will not notice this if you are eating a salad, but if you try eating a bagel or a steak, you will notice that you're muscles are weaker than usual).  Any change in the width of the face at this point is due to the botox lessening the resting tension in the muscle.3) Over the course of the next many weeks, the masters will slowly shrink and your face will slowly slim.  This is due to the muscle atrophying as a result of not working as hard (analogy: if you have your arm in a cast for a few weeks, it will be smaller than the other arm when the cast comes off).  The changes are gradual.  I wouldn't worry about not seeing dramatic results just yet.  But, if your masseter muscle doesn't feel weak, that may be a sign that the botox was not injected properly.

Thank you for your question. Botox in the masseter region usually takes longer than in the standard areas to take effect. I tend to use anywhere from 15 units (conservative treatment) to 50 units (for someone with really strong masseters) on each side to get the desired result. It may start within the first week but I tell my patients to wait three weeks before doing a more thorough evaluation. The treatment typically lasts 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. Once you stop using Botox, the masseter muscles will return to their original baseline when the effects of Botox wears off completely.As far as depth, the masseter muscle is a much bigger and deeper muscle than the frown, crows feet or forehead muscles.  I would make sure that your injector is well experienced with this region as it is considered a more advanced technique.

Some people develop large lower cheek girth from their chewing muscles (masseter) enlarging from clenching or grinding their teeth. Sometimes this is related to TMJ syndrome in which the joint of the jaw movement hurts. It is important to treat the muscles symmetrically so there is no imbalance that could exacerbate the TMJ. Injections need to be deep enough to affect the muscles. the enlargement will take time to diminish, even if the Botox was effective in relaxing the masseter muscle activity.

Your masseter muscles are deep and easily detected prior to and during injections. If your provider has said it takes two weeks to show visible slimming, I'd question that. Without seeing you in person, it's difficult to know how many units per side you'd need, but 20 units per side is a small amount for masseter reduction. Size reduction takes a fairly large amount of product. Results take several months to show, and the treatment is on-going.

Botox is normally injected into the muscle to obtain the best effect, no matter what area is treated.  For treatment with the masseter muscle, at two weeks after treatment, you should be able to see a difference in the muscle when you clench your teeth.  At this point, the muscle should not clench as much as it did before the treatment.  In regards to the size of the muscle at rest, this will take more time to develop.  Normally the masseter muscle does decrease in size somewhat with Botox, but it takes several months to begin to see this effect.  It may take several treatment sessions to obtain the optimal result.  

Hi amimatron, thank you for your question! Botox to the masseters is a great treatment option for people with large masseter muscles that are looking for a way to slim their face. Botox works by weakening the masseter muscle, once the muscle is weakened and cannot fully contract it will slowly decrease in size (atrophy), providing the slimming effect. Although Botox takes 2 weeks to reach full effect the muscle itself requires time to atrophy which is why slimming effects aren't typically seen until 1 month post injection, and can sometimes require multiple treatments before reaching desired results.
I've created a video that reviews treating masseter muscles with Botox. I hope you find this helpful in your research! 

Thank you for your question amimatron. I understand your concern. Botox is a purified protein used to address wrinkles associated with facial expression. When injected into the skin Botox will relax the muscles and smoothen out the overlying wrinkles. The most common areas of treatment are in the upper face. These include the horizontal lines seen on the upper forehead when one raises the brows, the vertical lines seen between the brows when one frowns (frown lines), and the crow's feet seen around the eyes when one smiles.It is difficult to make an assessment in the absence of consistent photographs before and after in the same lighting and angles for comparison. However, I hope the information provided here is useful.Botox can be placed in the masseter muscle in the lower face to contour the lower face and address pain associated with TMJ. In this area 20-40 units of Botox are used per side. Depending on the reason for the enlargement of the muscle, permanent results may be achieved. For example, some people have a habit of grinding, clenching, or biting their teeth subconsciously. Often times this happens in their sleep when they are not aware of it. Botox placed in this muscle will relax the muscle and the grinding, clenching, and/or biting will decrease. This will reduce the size of the muscle. If the brain gets accustomed to this and the person stops grinding, clenching, or biting, then the muscle will not become enlarged or as enlarged again. However, if the habit starts again, the muscle will likely get larger.

To determine if someone is a good candidate for this treatment it is necessary to look at a person’s lower face when biting and comparing it to when the person is not biting. If a bulge is seen on the outer portion of the jawline, then the person is likely a candidate. It can also be felt with the fingers when biting.
Every doctor has his/her own technique for placing Botox. For my patients I feel the muscle when they clench the teeth and place it directly in the muscle. Although I use the same needle as I use when treating wrinkles in the upper face, in this case the needle is placed deep into the muscle as opposed to superficially in the skin. If I had a patient with the concern described here I would want to look at the before and after pictures. Additional units may be necessary.With any injection, there are risks such as pain, bleeding, bruising, redness, swelling, tenderness, and infection. We take special precautions to minimize these risks such as using a painless technique. We also treat bruises with a laser as early as the next day. Bruises usually resolve within two weeks if untreated. After a laser treatment bruises usually resolve in 1-3 days, but may still take two weeks for full resolution. In addition to these risks, with Botox there is also a risk that the product spreads or diffuses to nearby structures. Spread to nearby muscles can lead to side effects such as the temporary appearance of droopy eyelids or a temporary asymmetric smile.

After a Botox treatment, I recommend that my patients avoid heat exposure, alcohol consumption, and strenuous exercise for 24 hours and not lie down flat for four hours. This is because all of these activities may possibly lead to the movement of the product and consequent side effects such as droopy eyelids. Although there have been no definitive studies shown that these actually occur and some physicians do not provide such aftercare instructions, in the absence of data I err on the side of caution and recommend that my patients avoid such activities.

Please consult with a doctor for specific recommendations. Good luck!

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. 

Botox is a great way to reduce the Masseter muscle and slim the face. It sounds like you had the correct dosage of Botox injected into the muscle. There are times when it can take several weeks or subsequent injections over time to decrease the size of the muscle. Please consult an expert in Botox for the best results. Best, Dr. Green