Background: Supraorbital hollowing from age-related volume loss or post-blepharoplasty overresection causes upper sulcus deflation. Hyaluronic acid (HA) fillers are frequently used in the upper eyelid, but prospective clinical follow-up data remain limited. Methods: This prospective single-centre cohort study enroled 46 adults with mild-moderate supraorbital hollowing who underwent supraperiosteal injection of cross-linked hyaluronic acid (0.2-0.4 mL per eyelid, Lorient No. 2) using a 25G blunt cannula via a lateral entry point. Standardised photographs were obtained at baseline and 6 months. Global Aesthetic Improvement Scale (GAIS; 1-5) was independently assessed at 6 months by two board-certified physicians blinded to each other's ratings based on comparative photographic evaluation, and separately by patients. Adverse events were prospectively recorded. Results: All patients completed 6-month follow-up. Mean physician GAIS was 4.3 +/- 0.5 and mean patient GAIS was 4.5 +/- 0.6; 91% were rated "very good" or "exceptional". Transient bruising (28%) and oedema (26%) resolved without intervention. No serious complications occurred. Conclusion: Deep supraperiosteal HA filler delivered by blunt cannula provided reproducible correction of supraorbital hollowing with high satisfaction and a low rate of self-limited adverse events at 6 months. (c) 2026 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.