BACKGROUND: Vacuum massage, or endermotherapy, is applied to scar tissue with the primary therapeutic goal of promoting structural or physiological changes. These changes are intended to enhance pliability, enabling the skin to possess the strength and elasticity required for normal mobility. The advantage of vacuum massage compared to therapist-generated manual massage is that it provides a standardized dosage using rollers and suction valves to mobilize the tissue. However, research documenting and supporting its impact on post-burn hypertrophic scar is lacking. Thus, this study was designed to objectively characterize the changes in scar elasticity, erythema, melanin, thickness, and transepidermal water loss immediately after a vacuum massage session and after a 12-week course of treatment compared to intra-individual matched control scars. METHODS: We conducted a prospective, randomized, controlled, within-patient, single-blinded clinical trial, initially designed as a fully-powered study but limited to a pilot study due to COVID-19 restrictions. Nineteen burn survivors consented to participate and 16 completed the study. Two homogeneous, intra-individual scars were randomized to usual care control or vacuum massage therapy plus usual care. Vacuum massage interventions were provided by a certified massage therapist three times per week for 12 weeks. Scar characteristics were evaluated every four weeks immediately before and after mechanical massage treatment. The evaluations included measurements of elasticity (Cutometer), erythema and melanin (Mexameter), transepidermal water loss (TEWL) (Tewameter), and thickness (high-frequency ultrasound). Linear mixed-model analyses were performed to test for immediate and long-term treatment effects. RESULTS: The ANOVA analyses revealed a non-significant time:treatment interaction for elasticity, erythema, melanin, thickness, or TEWL. There was a significant increase in elasticity and erythema and a decrease in TEWL in both the control and treatment sites over time with consistent standard care. However, there was no statistically significant immediate or long-term treatment effect for any of the skin characteristics. Nonetheless, the mean participant satisfaction was 4/5 (SD = 1.5) and the mean participant perception of effectiveness was 8/10 (SD = 1.9). CONCLUSIONS: This pilot study did not find a treatment benefit of vacuum massage therapy for elasticity, erythema, melanin, thickness or TEWL, but it did find an improvement with time in elasticity, erythema and TEWL. Despite the lack of objective improvement of the treated scar site, participants were satisfied with the results and believed vacuum massage was very effective. Further high-quality research is required to better inform clinicians patient education and treatment decisions for this costly, burdensome treatment approach that has high participant satisfaction.