The two timelines that matter
The muscle relaxation timeline (immediate, visible at 2 weeks) and the contour change timeline (months, visible at 12+ weeks) are separate. Patients expecting contour change at 2 weeks are disappointed; patients expecting pain relief at week 2 are usually rewarded. How the treatment itself works is covered on our masseter treatment page.
Week-by-week realistic timeline
Week 2: full muscle relaxation, no visible contour change yet. Week 4-6: subtle softening starts to be photographable. Week 8-12: visible contour change in photographs. Week 12-16: peak result from a single session.
Cumulative effect across sessions
After session 1: ~50% of maximum change. After session 2 (4-6 months later): ~75%. After session 3: ~90%. Best evaluated over a year, not over weeks. How long each treatment lasts is covered in how long masseter treatment lasts.
What determines how much change is realistic
Baseline muscle bulk, bone structure (masseter treatment can't reduce bone), whether the underlying bite cause is addressed, dosing approach, and individual response. For the full range of options, see our guide to jaw slimming without surgery.
Honest expectations
Realistic: subtle but noticeable contour softening, better outcomes combined with a splint. Unrealistic: dramatic slimming in bone-driven width, visible change at week 2, or resolution of TMJ pain from aesthetic medicine alone.
By Dr Vishal Patel, BDS, MSc Aesthetic & Restorative Dentistry, GDC 103127, sole aesthetic prescriber DWL. Last reviewed 2026-05-17.
