Obtained from the spiny dogfish shark and hammerhead shark (1), shark cartilage is promoted as a dietary supplement to treat cancer (2) (3) (4) (5), arthritis, osteoporosis, Kaposi sarcoma (6), macular degeneration, psoriasis (7), and inflammatory disorders.
Shark cartilage extracts show antiangiogenic and antitumor activities in vitro (8) (9) and in animal models (10) (11) (12) (13), but clinical use remains controversial due to lack of bioavailability data and unsatisfactory patient outcomes in clinical trials (1) (14).
Shark cartilage has also been studied for Kaposi sarcoma (6), metastatic renal cell carcinoma (5), and multiple myeloma (4) in early phase clinical trials. Neovastat (AE-941), a purified shark cartilage extract, did not improve survival in patients with non-small cell lung cancer (15), but is effective against psoriasis (7).
Most trials report low toxicity, but regular consumption of a shark cartilage supplement was associated with reversible hepatic dysfunction in a 57-year-old man (16). The Federal Trade Commission has barred three manufacturers from making unsubstantiated claims of efficacy for their shark cartilage products. Shark cartilage should not be confused with bovine cartilage.