The aim of this prospective supplement summer registry study was to evaluate the efficacy of Pycnogenol® in controlling symptoms of chronic venous insufficiency (CVI) and microcirculatory parameters: venous hypertension and microangiopathy. Pycnogenol® (Horphag Research) is the standardized extract of the bark of Pinus Pinaster.During the summer period between June and August 142 patients were split into three groups: 1) Pycnogenol® 150 mg/day; 2) compression stockings; 3) and compression + Pycnogenol®.Venous pressure (ambulatory venous pressure, AVP) and refilling time (RT), microcirculatory and clinical measurements were comparable at inclusion. At 8 weeks variations in skin flux (RF), rate of ankle swelling (RAS), skin PO2-PCO2, Analogue Symptomatic Score (ASLS), Venous Disability and severity Scores and local oxidative stress (OS) indicated a statistically significant improvement by Pycnogenol® both as a single supplement and in association with compression in comparison with baseline. Pycnogenol® significantly improved the microcirculation in comparison with compression (P<0.05). The combined effects of Pycnogenol+compression produced the best results in most measurements. The summer study penalized compression - in a very hot summer - with many drops out. No side effects due to supplementation were observed; tolerability was optimal. The tolerability to stocking was less than optimal (70% of compression not correctly used). Pycnogenol® alone was more effective than compression alone. The increase (P<0.05) in skin O2 and the decrease in PCO2 were associated with the decrease in skin flux. The variations in capillary filtration (RAS) were the most important microcirculation changes. RAS is directly associated with swelling, the hallmark of CVI. Pycnogenol® in both Pycnogenol groups significantly improved RAS in comparison with compression only (P<0.05). The decrease in OS in both Pycnogenol® groups was significant in comparison with compression only (P<0.05). A lower OS is an important micro-metabolic indication of a better capillary bed with better nutritional, perfusional exchanges. The clinical measurements followed the patterns of the microcirculation with the supplement groups performing statistically better (P<0.002) than the compression-only.This "summer registry" study confirms the clinical and microcirculatory efficacy of Pycnogenol in CVI and venous microangiopathy. The study indicates the significant clinical role of Pycnogenol® (both as a single treatment and in association with compression) in the management, treatment and control of this common clinical problem.