Frown Lines

Frown lines, also called glabellar lines or the eleven lines, are the vertical creases that form between the brows when the face expresses concentration, concern or irritation. Despite their small surface area, they are produced by the interaction of several muscles: the corrugator supercilii, which pulls the brows down and medially, and the procerus, which pulls the skin of the nasion downward. Together these muscles form the glabellar complex, and repeated contraction over years etches vertical lines into the overlying skin, initially visible only on expression and eventually static at rest. The depth and number of frown lines vary between individuals. Some people develop a single central line, others the characteristic two-line pattern, and a small proportion develop three or more parallel creases. Genetics determine the pattern, but the rate at which dynamic lines become static depends on cumulative expression, sun damage, smoking and overall dermal quality. A heavily-expressive brow in a patient with thin, sun-damaged skin will etch lines faster than a less expressive brow in a patient with thicker skin and disciplined UV protection. Men and women develop frown lines at similar rates but men often require higher doses of toxin to achieve the same clinical effect because the corrugator bulk is typically greater. Botulinum toxin is the standard first-line treatment. The glabellar complex is the only aesthetic toxin indication that is actually licensed in the UK for botulinum toxin type A products such as Azzalure, and it is the area with the largest published evidence base for dosing and technique. Injected into the corrugator on each side and the procerus centrally, toxin reduces the contractile strength of the complex so the overlying skin no longer creases on expression. Results begin at days three to five, settle by two weeks, and last three to four months. For deeply etched static lines that remain visible when the face is at rest after several cycles of toxin, a small amount of hyaluronic-acid filler can be placed very superficially to soften the residual groove, though this is technique-sensitive and carries vascular risks given the proximity to the supratrochlear and supraorbital vessels. Patients with a history of neuromuscular disease, pregnancy or breastfeeding, or an active infection at the injection site are not candidates. A proper consultation also discusses realistic onset timing and the need for a two-week review to adjust dose at follow-up.