BACKGROUND: Resveratrol, a dietary supplement that intervenes in cellular metabolism, has been shown to reduce aortic growth rate in a mouse model of Marfan syndrome (MFS), a condition associated in humans with life-threatening aortic complications, often preceded by aortic dilatation. The primary objective of this study was to investigate the effects of resveratrol on aortic growth rate in patients with MFS . METHODS: In this investigator-initiated, single-arm open-label multicentre trial, we analysed resveratrol treatment in adults aged 18-50 years with MFS. The primary endpoint was the change in estimated annual aortic growth at five predefined levels in the thoracic aorta after 1 year of resveratrol treatment, evaluated using a linear mixed model. Aortic diameters were measured by cardiac MRI at three time points to analyse the annual aortic expansion rate before and after initiation of treatment. Additionally, annual aortic growth was compared with growth in a previously conducted losartan randomised clinical trial. RESULTS: 898 patients were screened of which 19% (168/898) patients met the inclusion criteria.36% (61/168) patients signed informed consent and 93% (57/61) aged 37±9 years, of which 28 males (49%) were included in the final analysis of the study. 46% (26/57) had undergone aortic root replacement prior to the study. Aortic root diameters remained stable after 1.2±0.3 years of resveratrol administration. A trend towards a decrease in estimated growth rate (mm/year) was observed in the aortic root (from 0.39±0.06 to -0.13±0.23, p=0.072), ascending aorta (from 0.40±0.05 to -0.01±0.18, p=0.072) and distal descending aorta (from 0.32±0.04 to 0.01±0.14, p=0.072). CONCLUSION: Resveratrol treatment for 1 year may stabilise the aortic growth rate in adult patients with MFS. However, a subsequent randomised clinical trial with a longer follow-up duration and a larger study cohort is needed to establish an actual long-term beneficial effect of this dietary supplement in patients with MFS. TRIAL REGISTRATION NUMBER: NL66127.018.18.