Diosmin is a flavonoid compound derived mainly from citrus fruits and is commonly used in combination with hesperidin in phlebotropic drugs. Its primary use is in the treatment of chronic venous insufficiency (CVI), hemorrhoids, and related vascular conditions, including spider veins (telangiectasias). Several clinical studies and systematic reviews have evaluated the effectiveness of micronized purified flavonoid fraction (MPFF)—which contains diosmin—for improving venous tone, reducing capillary permeability, and alleviating symptoms such as leg swelling, pain, and discomfort related to venous disorders.

For spider veins specifically, the evidence is less robust than for more severe forms of venous insufficiency or varicose veins. Most clinical trials group spider veins with other manifestations of venous insufficiency and rarely study them as an isolated endpoint. However, diosmin has demonstrated efficacy in improving microcirculation and reducing edema, which theoretically could improve the appearance and symptoms of spider veins. Meta-analyses and clinical guidelines (e.g., from the European Society for Vascular Surgery) often recommend diosmin-containing preparations as adjunctive therapy for venous disorders, though the degree of benefit for spider veins alone is modest and not universally supported by high-quality, large-scale trials.

In summary, while diosmin is scientifically validated for broader venous insufficiency and related symptoms, the level of evidence specifically for spider veins is moderate and largely extrapolated from studies on more severe venous disease.