COSMEDOCS
    Harley Street Doctors • Since 2007

    Medically reviewed by Dr Ahmed Haq, Medical Director, Cosmedocs Harley StreetGMC 6078057Last reviewed

    Masseter Botox Dosage: How Many Units Do You Actually Need?

    Doctor-Led
    Bruxism + Slimming
    Harley Street
    Evidence-Based

    Masseter Botox typically uses 30–60 units total — 15–30 per side. Below 25 units per side you may achieve mild bruxism relief but rarely visible slimming. Men generally need more units than women due to larger, stronger masseter muscles. Under-dosing is the single most common reason masseter Botox "doesn't work".

    Quick Answer

    • Bruxism relief (mild): 20–25 units per side
    • Bruxism relief (severe): 25–35 units per side
    • Visible jaw slimming (women): 25–35 units per side
    • Visible jaw slimming (men): 30–40 units per side
    • First treatment minimum: 25 units per side — anything less risks no result

    Two Goals, Two Doses

    Masseter Botox is requested for two distinct reasons — and the dose depends on which one you want. Bruxism (teeth grinding, clenching, jaw tension, tension headaches) responds to lower doses because partial muscle weakening is enough to break the grinding cycle. Cosmetic jaw slimming requires the muscle to atrophy enough to visibly narrow the lower face — and atrophy is dose-dependent.

    At Cosmedocs, we always confirm your goal before deciding the dose. A patient who wants both — relief and slimming — almost always sits in the 30–35 units-per-side range.

    Dosing Table

    GoalWomen / sideMen / sideTotal
    Mild bruxism only202540–50
    Severe bruxism25–3030–3555–65
    Cosmetic slimming25–3530–4055–75
    Slimming + bruxism30–3535–4065–75

    Why Repeat Treatments Slim More

    Masseter atrophy is cumulative. A first treatment shrinks the muscle by roughly 20–30%. A second treatment four to six months later (before the muscle fully recovers) compounds the effect — by the third or fourth session, many patients reach a stable slimmer jawline that holds for 6–9 months between top-ups. This is why budgeting masseter Botox as a 12–18 month project, not a single session, gives the best long-term result.

    The "20-unit special" warning

    Some clinics advertise masseter Botox at 20 units total (10 per side) to hit a low headline price. At that dose, the muscle is barely weakened — bruxism returns within weeks and there is no slimming. You then assume Botox does not work for you, when in fact you were under-dosed. Always ask the per-side unit count before booking.

    Common Questions

    Masseter Botox typically uses 30–60 units total (15–30 per side). Women usually require 30–50 units, men require 40–60. Smaller doses produce only short-lived bruxism relief; doses below 25 per side rarely give visible slimming.

    Visible jaw slimming requires at least 25 units per side, more typically 30–40 per side. Below this threshold the muscle atrophies too little for the change to be cosmetically meaningful.

    Bruxism relief is achievable with lower doses — 20–25 units per side is often enough. Patients with severe nocturnal grinding or significant masseter hypertrophy may need 30+ per side for sustained relief.

    First treatment: 3–4 months. With repeat sessions every 4–6 months, the muscle progressively weakens and the slimming effect lasts longer — often 6+ months by the third cycle.

    When dosed and placed correctly, no. Risks like an asymmetric smile or 'paradoxical bulging' come from injecting too superficially or outside the safe zone — both are technique problems, not dose problems.

    Yes, for mild bruxism or if you only want preventative relief. But you should not expect visible slimming. Under-dosing is the most common cause of disappointed patients.

    Yes. Male masseters are typically 25–40% larger and stronger. A reasonable starting dose for men is 30 units per side, escalating to 40 if hypertrophy is significant.

    Continue reading

    Bruxism Botox TreatmentBotox Units ExplainedTooth Chipping & GrindingBefore & After Masseter Botox