Lingzhi (Ganoderma lucidum), also known as reishi mushroom, has a long history of use in traditional Chinese medicine. It is traditionally believed to "invigorate blood," "nourish the heart," and "support longevity." There are anecdotal and folkloric claims that lingzhi benefits blood vessels and promotes healthy circulation, which implies a supportive role for capillaries and microcirculation. However, these beliefs are not rooted in rigorous scientific investigation of lingzhi’s specific effects on capillary function or integrity.

Scientific studies have explored lingzhi’s bioactive compounds, such as triterpenoids and polysaccharides, for their antioxidant and anti-inflammatory effects. Some in vitro and animal studies suggest these compounds may protect endothelial cells (which line blood vessels) from oxidative stress and inflammation. Despite this, direct evidence supporting the use of lingzhi specifically to strengthen or support capillaries in humans is minimal or lacking.

In summary, while there is a traditional rationale for using lingzhi to support the vascular system, and some preliminary scientific interest in its vascular effects, robust clinical evidence for its use in capillary support is absent. The evidence rating reflects the traditional foundation and very limited direct scientific validation for this specific use.