Advanced botulinum toxin: beyond the licensed upper face
How off-label toxin use in the lower face, neck and masseter differs from licensed upper-face treatment, and where the burden of knowledge falls.
The licensed cosmetic indications for botulinum toxin type A in the United Kingdom cover a narrow band of the face: the glabellar complex, the lateral canthal lines and the frontalis. Everything else that is routinely described in the aesthetic literature — the nasal tip, the gummy smile, the depressor anguli oris, the mentalis, the platysma, the masseter — sits outside those marketing authorisations. That is what “advanced” means in practice. It is not a statement about difficulty; it is a statement about regulatory status.
Off-label is not the same as unevidenced
A licence describes what a manufacturer has applied for and paid to have assessed. It does not describe the boundary of published knowledge. Several off-label areas are supported by substantial peer-reviewed literature: platysmal band treatment and the posterior platysma approach known as the Nefertiti lift have been examined anatomically and clinically, and masseter reduction for bigonial width has accumulated its own review literature with dosing ranges and retreatment intervals.
The inverse also holds. Off-label does not confer evidence either. Some advanced areas rest on case series, expert consensus and technique papers rather than controlled trials, and the honest position is that the quality of support varies considerably from region to region. A practitioner using an area off-label carries the full burden of knowing which of those two situations applies.
The regions and what changes
Nasal tip lift targets the depressor septi nasi, addressing tip descent on animation. The relevant anatomy is small, midline and close to the columella base.
Gummy smile treatment reduces activity in the levator labii superioris alaeque nasi complex. It is dose-sensitive to an unusual degree — the difference between a corrected smile line and an asymmetric, functionally impaired upper lip is measured in single units and a few millimetres of placement.
Depressor anguli oris treatment addresses the downturned oral commissure. The muscle sits close to the depressor labii inferioris, and diffusion between the two is the standard explanation for the asymmetric lower lip that follows a misplaced injection.
Mentalis treatment addresses chin dimpling. Platysmal bands and the Nefertiti approach address the cervicomental contour and jawline definition; the muscle is thin, superficial and continuous with the SMAS, so depth control matters more than in most upper-face work.
Masseter treatment is the outlier in this list. It is a large, deep, functionally important muscle of mastication, and the treatment goal — bulk reduction — is achieved through disuse atrophy over weeks, not through the immediate relaxation seen elsewhere.
Hyperhidrosis of the axilla, palms and soles operates through a different target entirely: the cholinergic sympathetic innervation of eccrine sweat glands rather than the neuromuscular junction. Axillary hyperhidrosis is separately licensed in many markets; the palmar and plantar applications generally are not.
Where the burden sits
Three consequences follow from off-label use. First, the anatomical margin for error is narrower, because the lower face and neck contain muscles that share function with speech, swallowing and oral competence. Second, the practitioner cannot rely on a summary of product characteristics for dose guidance, and must instead be able to cite the literature they are working from. Third, consent must reflect the off-label status explicitly, alongside the specific functional risks of the region.
The bibliometric picture of the field shows a literature dominated by a small number of heavily cited technique and anatomy papers. That concentration is a useful signal: it indicates where consensus genuinely exists, and by omission, where it does not.
