Why Men Need Double the Botox Dose for Jaw Slimming

Masseter Botox Dosing:

Why Men Need Twice the Amount Women Do

Check This Before You Read On

Q. I heard the masseter Botox dose is the same for men and women —

is that true?

A. No, it's not.

If 40 units is standard for women,

80 units is the baseline for men.

Male masseter muscles are 1.5 to 2 times larger in volume, so using the same dose

typically delivers only half the effect in men.

Q. Why does that difference exist?

A. It comes down to the thickness and density

of the masseter muscle itself.

Botox works per unit area of muscle tissue —

so a thicker muscle requires

a proportionally higher dose to achieve adequate relaxation.

Masseter Botox Dosing:

If You've Been Told Men and Women Need the Same Amount

If you found this post while searching for masseter Botox dosing, you're probably wondering

"what's the right number of units for me?"

In particular, I frequently see male patients who tell me

"I had it done somewhere else, but it barely made a difference."

Masseter Botox is a non-surgical procedure that involves injecting neurotoxin into the masseter —

the chewing muscle along the sides of the jaw —

to gradually relax and reduce it.

It's sometimes compared to jaw reduction surgery,

but that procedure involves shaving the bone itself.

Botox, by contrast, targets only the muscle —

making it a non-surgical alternative with a very different profile.

The Downtime, cost, and reversibility

are completely different from surgery.

Same Procedure —

Why Do Some People See Results and Others Don't?

Key Insight from Dr. Wi Young-jin

If the standard dose for women is 40 units,

men should start at 80 units.

With 1.5 to 2 times the muscle mass,

the same dose simply won't deliver adequate results for most male patients.

This is something I hear in the clinic

two or three times a week.

Last week, a 39-year-old male patient came in.

He had received 50 units of masseter Botox at another clinic,

and after three weeks, he noticed no change at all.

Looking at his records, that clinic used 50 units

as a universal standard regardless of gender.

Here's where it gets nuanced —

for female patients, that dose often works just fine.

The issue is the male masseter. When we measure thickness via ultrasound,

women average around 10mm,

while men typically measure around 15mm.

In terms of volume — not just surface area —

that's a difference of 1.5 to 2 times.

So what happens when you inject the same dose into a muscle that's twice the size?

The effective toxin concentration per unit volume drops by half —

meaning either the results don't show at all,

or they wear off within two months.

For this patient, I administered an additional 30 units,

bringing his total to 80 units.

Two weeks later, he came back and said,

"I can finally feel the muscle relaxing when I chew" —

and he was very satisfied with the outcome.

Generally, I recommend waiting at least one month between sessions due to tolerance concerns,

but in his case, the initial dose had produced virtually no effect,

so a quicker top-up was clinically appropriate.

It's also important to understand the expected timeline.

Around day 3, you may notice a subtle reduction in muscle tension,

and more noticeable changes typically appear by week 2.

Visible jawline slimming usually takes 4 to 6 weeks.

On average, results last about 3 months,

though some patients maintain effects for up to 6 months.

So when patients tell me "it's been a week and I don't see anything,"

my advice is always the same:

give it at least 2 weeks before drawing any conclusions.

Dr. Wi Young-jin's Key Takeaways

Masseter Botox dosing should be based on muscle volume —

not gender.

If 40 units is the standard for women,

80 units is the starting point for men.

And results shouldn't be judged immediately after the procedure —

wait at least 2 weeks for an accurate assessment.

Masseter Botox —

Which Type Are You?

There's one important point I always make sure to mention:

as the dose increases,

so does the risk of antibody formation.

Male patients who receive 100 units frequently

can sometimes experience diminishing returns over time.

That's why I advise male patients to start with a sufficient dose for their first session,

then reduce the amount and extend the interval

from the second session onward.

The 3 Questions I Get

Most Often in the Clinic

Q1. Does that mean all men

need 80 units or more?

Not necessarily — some men have relatively thin masseters,

and some women have quite thick ones.

That's why we always assess the muscle directly

by palpation and measurement during the consultation.

The 80-unit figure is an average starting point for men —

it doesn't mean we administer a high dose without proper evaluation.

Q2. Is it safer to split the dose across two sessions?

I generally don't recommend intentionally splitting the dose

into two smaller sessions.

The muscle needs an adequate dose in a single session

to relax properly and respond well.

Splitting an insufficient dose tends to produce inconsistent results

and may actually increase the risk of tolerance over time.

Q3. What if my cheeks look hollow after masseter Botox?

Cheek hollowing tends to occur

in patients who already have limited facial fat volume.

As the masseter muscle reduces in size,

the area beneath the cheekbone can appear sunken.

For patients with this concern, it's much better to adjust the dosing upfront

or consider combining the procedure

with a complementary contouring treatment.

If there's one thing to take away from today —

masseter Botox dosing should be tailored to your muscle volume,

not simply your gender.

Please keep that in mind.

In my next post, I'll be covering

'How to Time Your Masseter Botox Touch-Up Sessions.'

This has been Dr. Wi Young-jin.

Further Reading

• Why Do My Cheeks Look Hollow After Masseter Botox?

• 10 Sessions of Masseter Botox With No Results — What Changed When I Tried Parotid Gland Botox