Ingredient Beauty BenefitsRoute · Injection
Botulinum toxin: the effect over placebo was clear in two phase 3 trials, both run by the manufacturer
In two phase 3 randomised, double-blind, placebo-controlled trials (730 participants in total), both the primary and key secondary endpoints were significantly better than placebo (P < .0001 for each). All 59 products registered in Korea are prescription-only.
Last checked Sep 16, 2026
Botulinum toxin temporarily blocks nerve signalling to muscle, softening the lines that expressions create. It is the best-evidenced procedure on this site.
And yet it sits at moderate. One reason: the trials we verified are the manufacturer's own product-registration trials. This site's criteria for strong evidence cannot be met on manufacturer funding alone.
It is not that trials are scarce here; there are many. It is that what we checked and registered is that one paper covering two trials, and its funding is not in doubt.
What is established
Upper facial lines: significantly better than placebo in two phase 3 trials
Two phase 3 trials (ULTRA I and ULTRA II) in adults aged 18 and over. Participants with moderate-to-severe glabellar, forehead and lateral canthal lines at maximum contraction were randomised 2:1:1 to up to 64 units of incobotulinumtoxinA or placebo.
Three hundred sixty-two and 368 people respectively — 730 in total — received treatment. In both studies the treatment was significantly more effective than placebo on the primary endpoints and the key secondary endpoints (P < .0001 for each). Results in the open-label extension were consistent.
Assessment used investigator ratings on five-point scales. That the endpoint is a trained assessor's score rather than self-reported improvement makes this result sturdier.
What remains is funding. These are a manufacturer's registration trials, and that is why this entry sits at moderate.
- Randomised controlled trial in people (2) · 730 participants · Compared with vehicle (same formula minus the active) · Funding manufacturer-funded · Endpoint scores from blinded assessors PMID 39475143
All 59 products registered in Korea are prescription-only
The Korean drug register lists 59 products with botulinum toxin as the active ingredient, all prescription-only (checked 16 September 2026). Products such as Nabota (Clostridium botulinum toxin type A) are among them.
It requires a doctor's prescription and a procedure. This page does not cover units, injection sites or intervals — those are settled in consultation.
Known risks
- Pain, swelling and bruising at the injection site are common.
- Eyelid droop, changes in brow position and facial asymmetry are reported. These usually resolve, but it can take weeks to months.
- Headache and flu-like symptoms are reported.
- Rarely, toxin spread beyond the injection site affecting swallowing or breathing has been reported. If you have difficulty swallowing or breathing, seek care immediately.
- If you have a neuromuscular condition, say so before the procedure.
What is not established
- The long-term effects of repeated treatment are not established. Muscle atrophy and resistance are both discussed.
- Units differ between products and do not convert between them. Comparisons between products are not covered here.
- How long the effect lasts varies considerably between people.
Whether to have it done is a decision to make with a doctor.
What this article relies on
- 의약품안전나라 — 의약품등 정보검색 (품목 허가사항)식품의약품안전처 · Checked on 2026-09-16
- PubMed — 미국 국립의학도서관 문헌 데이터베이스National Library of Medicine · Checked on 2026-09-16