Is Skin Botox the Same Drug as Masseter Botox? — Plane, Dose and Licence Differ
Of the botulinum toxin questions we hear, the one that tangles most often is this one. Skin botox and masseter botox use the same class of drug in almost different procedures: a different plane, a different dose design, and a different approved indication. Because both are called “botox”, it is easy to carry an expectation about duration or dose from one to the other, and that is where the misunderstanding starts.
The short answer
The drug is the same botulinum toxin, but masseter treatment places a relatively large dose inside the muscle at a few points, while skin botox is diluted and placed in a shallow plane of the skin across many points. Benign masseteric hypertrophy was approved in Korea in August 2023 with dosing of 48 Units over 6 points; placing toxin in a shallow plane to act on sebum and pores is an off-licence use. The human data differs too: the masseter indication has several placebo-controlled randomised trials, while skin botox rests mostly on small split-face studies. Miso Clinic in Daegu (4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, South Korea; +82-53-428-2700) designs the dose and the points separately for each area because the target structure is different.
Same drug, different plane
Botulinum toxin reduces the signal a nerve sends to a muscle. So the depth at which it is placed decides most of the character of the treatment.
- Masseter — placed inside the chewing muscle. The aim is a muscle that is used less and becomes thinner.
- Skin botox — placed diluted in a shallow plane of the skin. The aim is not a smaller muscle but a change in sebum, pores and texture.
That is why “will a lot of skin botox make my face smaller?” is answered with a difference in design. Diluted toxin in a shallow plane is not a design for reducing muscle thickness.
The comparison between skin botox and ordinary botox, organised by depth, is in its own column — onset, duration and approved doses covers the licensed dosing this one refers to.
The dose and point design differ
For the masseter the Korean approved dosing reads 48 Units over 6 points — a design that concentrates the dose. Skin botox goes the other way: diluted and spread thinly over many points.
One finding deserves emphasis here. Raising the dose per point did not automatically produce a stronger or longer result. In a randomised, double-blind comparison of 10 against 20 Units in the forehead of 42 women, 4 Units per point was neither stronger nor longer-lasting than 2 Units.
The same study observed something else: sebum fell at the injection points but rose beyond a 2.5 cm radius at weeks 2, 4 and 8. The spacing between points is part of the design, not a detail.
A Unit is not a volume
This is the most common misunderstanding. A Unit is biological potency, not an amount of liquid. And because the potency assay differs between manufacturers, Units do not convert 1:1 between products.
“I had so many units” therefore does not compare across clinics or products. Which product, which area, and how many points it was divided into have to travel with the number for it to mean anything.
The approved indications differ
Benign masseteric hypertrophy was approved by the Korean MFDS in August 2023 for a domestic product. Approved indications differ by product, so we check the licence of the product in use separately.
Placing toxin in a shallow plane of the skin to act on sebum and pores is an off-licence use. Off-licence does not mean wrong, but knowing and consenting to it is different from not being told. We say so before the treatment.
What the human data shows
Masseter
- A meta-analysis of five placebo-controlled randomised trials (536 patients) found thickness, prominence and satisfaction improved against placebo. Heterogeneity was high, so the size of the reduction should be read with care, and the review concluded that the optimal dose and schedule are not established.
- In a phase 2b trial, prominence of grade 3 or less at day 90 was reached by 90.6% (48 Units) and 91.3% (72 Units) against 21.7% for placebo. Authors include manufacturer employees.
Skin botox
- In a double-blind split-face study of 18 people, sebum production and under-eye wrinkles showed no significant difference; pores improved at week 2 only, texture at week 8, and nasolabial wrinkles to week 12.
- In a multicentre randomised double-blind study of 49 people in the scalp, sebum was significantly lower at 1 and 3 months and no different at 4 and 6 months. That is scalp data, not facial data.
In short, the masseter evidence is thicker, and the skin botox evidence is small and splits by which measure you look at. That is not an argument against skin botox; it is an argument for setting expectations at the level the data supports.
What happens when the dose goes up
Dose is not a variable that improves with size. Two reported observations are worth keeping.
- In the intradermal cheek study, one subject who received 30 Units in a single cheek reported facial palsy; there were no adverse events at 20 Units (18-subject study).
- In the masseter phase 2 trial, 4 patients in the 96-Unit arm reported a local effect on smiling (authors include manufacturer employees).
So the design aims not at “a lot” but at the least that reaches the target structure. Adding at a two-week review is better than putting in a generous dose and waiting for it to wear off.
Summary — established and not established
Established
- Benign masseteric hypertrophy was approved in Korea in August 2023, with dosing recorded as 48 Units over 6 points.
- Placing toxin in a shallow plane of the skin is an off-licence use.
- 4 Units per point was neither stronger nor longer-lasting than 2 Units (42 people, randomised, double-blind).
- Sebum beyond a 2.5 cm radius from the injection point rose at weeks 2, 4 and 8 in the same study.
- A Unit is potency and does not convert 1:1 between products.
Not established
- The optimal dilution, number of points or spacing for skin botox — we found no human comparison.
- How long skin botox reduces sebum — the facial data is small and splits by measure.
- The optimal dose and schedule for the masseter — the meta-analysis concluded they are not established.
- Any interaction when both are done on the same day — no comparative data.
Skin botox and masseter botox: frequently asked questions
Does skin botox make the face smaller?
That is not its design. Skin botox is diluted and placed in a shallow plane to act on sebum, pores and texture. Reducing muscle thickness is what the masseter treatment, placed inside the muscle, is for.
If the number of units is the same, is the amount the same everywhere?
No. A Unit is biological potency rather than a volume, and potency assays differ between manufacturers, so Units do not convert 1:1 between products. The product, the area and the number of points have to be confirmed alongside the number.
Is skin botox an approved treatment?
Placing toxin in a shallow plane of the skin to act on sebum and pores is an off-licence use. Benign masseteric hypertrophy has a Korean approval from August 2023. We explain the difference before treatment.
Can both be done on the same day?
They are different areas, so they are sometimes combined. There is no comparative data on doing both on the same day, so we judge from the total dose and the areas involved.
Does a higher dose last longer?
That is not what was reported. In a randomised double-blind study of 42 people, 4 Units per point was neither stronger nor longer-lasting than 2 Units. Meanwhile one subject who received 30 Units in a single cheek reported facial palsy.
Read next
Product pages
No separate English product page yet — the approved doses, the label wording and the adverse-event rates for botulinum toxin are collected in our onset and duration column.
Who wrote this
Written and reviewed by Lee Chi-Hak, MD, director of Miso Clinic, Daegu. The treatment standards and injection design set out here are the ones we use in practice.
| Medical director | Lee Chi-Hak, MD |
|---|---|
| Address | 4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, South Korea · Exit 1, Kyungpook National University Hospital Station |
| Phone | +82-53-428-2700 |
| Hours | Weekdays 11:00–19:00 (lunch 13:00–14:00) / Saturday 10:00–16:00 (no lunch break) / Closed Sundays and public holidays |
| Columns | All clinical columns |
| Reference library | All booster and device references |
References
- Miso Clinic botulinum toxin notes — a Unit is biological potency, not a volume, and because potency assays differ between manufacturers, Units do not convert 1:1 between products. Target muscle by area, dose and point design, a check at two weeks, and a minimum of three months between treatments of the same area.
- Korean approval for benign masseteric hypertrophy — a domestic product was approved by the MFDS in August 2023, with dosing of 48 Units over 6 points (information carried by the Korean Pharmaceutical Information Center on the basis of the approved product information). Approved indications differ by product, so the licence of the product in use is checked separately.
- US FDA prescribing information (BOTOX Cosmetic, onabotulinumtoxinA, revised October 2024) — onset “one to two days after injection, increasing in intensity during the first week”, duration “approximately 3-4 months”, re-treatment “more frequently than every 3 months have not been clinically evaluated”, cumulative ceiling 360 Units / 3 months.
- Intradermal toxin in the cheek, double-blind split-face — Shin DM et al., Ann Dermatol 2022;34(6):442–450, PMID 36478426. 18 subjects, incobotulinumtoxinA in one cheek and saline in the other. No significant difference in sebum production or under-eye wrinkles; pores improved at week 2 only, texture at week 8 and nasolabial wrinkles to week 12. One subject who received 30 Units in one cheek reported facial palsy; there were no adverse events at 20 Units.
- Sebum by distance after intramuscular forehead injection — Min P et al., Aesthet Surg J 2015;35(5):600–610, PMID 25825422. 42 women, 10 Units against 20 Units, randomised and double-blind. Sebum fell at the injection points but rose beyond a 2.5 cm radius at weeks 2, 4 and 8; 4 Units per point was neither stronger nor longer-lasting than 2 Units, and values returned to baseline by week 16.
- Intradermal toxin in the scalp, multicentre randomised double-blind — Li Y et al., Aesthet Surg J 2023;43(1):NP38–NP48, PMID 36004504. 49 subjects (25 toxin · 24 saline), one session of 50–65 Units. Sebum was significantly lower at 1 and 3 months and no different at 4 and 6 months. This is scalp data, not facial data.
- Masseter prominence, phase 2b — Liew S et al., Aesthet Surg J 2025;45(10):1043–1050, PMID 40111171. 48 Units in 53 patients · 72 Units in 46 · placebo in 46, single treatment. At day 90, prominence of grade 3 or less was reached by 90.6% and 91.3% against 21.7% for placebo. Authors include manufacturer (Allergan) employees.
- Masseter prominence, phase 2 (24–96 Units) — Carruthers J et al., J Am Acad Dermatol 2025;92(3):464–472, PMID 39522729. 187 patients, re-injection at day 180 if needed. Lower-face volume and prominence fell against placebo, there was no clinical change in jawbone or teeth, and 4 patients in the 96-Unit arm reported a local effect on smiling. Authors include manufacturer employees.
- Meta-analysis in masseteric hypertrophy — Machado GF et al., J Plast Reconstr Aesthet Surg 2026;119:212–225, PMID 42379083. Five placebo-controlled randomised trials, 536 patients. Thickness, prominence and satisfaction improved against placebo, but heterogeneity was high, so the size of the reduction should be read with care, and the review concluded that the optimal dose and schedule are not established.
- Medical advertising law — Medical Service Act of Korea, Article 56(2), which prohibits testimonial advertising, comparison with other clinics, superlative claims and advertising that guarantees or implies a guaranteed treatment effect.
- Miso Clinic practice guidance — indication criteria, site-by-site design, and the explanation and consent procedure. This is the source for every sentence marked as clinical judgement.
Everything in this column is general information and does not replace medical diagnosis or treatment. Effects and side effects vary with individual skin condition, age and underlying illness, and the same result is not guaranteed for everyone. Any decision to proceed should be made in an in-person consultation with a physician.