Icariin is an inhibitor of human recombinant PDE5 with an IC₅₀ value of 5.9 μM. It is a prenylated flavonol that has been shown to have anti-cancer and antioxidant activity. At a concentration of 1 x 107 mol/L, Icariin induces differentiation of cardiomyocytes and upregulates the expression of cardiac genes. At 20 μg/ml, Icariin increases the proliferation and differentiation of cultured human osteoblasts, which appears to be mediated in part by upregulating bone morphogenetic protein 2 mRNA.

Icariin, a type of flavonoid, is the major bioactive component in Herba Epimedii which has been historically used in combination with other herbs to treat skeletal diseases in traditional Chinese medicine (TCM). It has been reported that icariin shows various pharmacological effects such as osteoprotective effect, antioxidative effect, osteoprotective effect, neuroprotective effect, cardiovascular protective effect, anti-cancer effect, anti-inflammation effect, immunoprotective effect and reproductive function.

Icariin is one of the major flavonoids of the herb Epimedium, which has long been used in Tranditional Chinese Medicine to treat bone fracture and prevent osteoporosis. Research has shown that icariin should be an effective component for the bone-strengthening activity of the herb Epimedium, and one of the possible mechanisms for this activity is to stimulate the proliferation and enhance the osteogenic differentiation of marrow stromal cells. Icariin is reported to prevent and treat sexual dysfunction related diseases and improve the use of vasoconstriction. Icariin is used to prepare angiotensin converting enzyme inhibitor medicines, which can be used to treat hypertension-complicated coronary diseases.