
The commonly used name for the preparation is shark cartilage. Commercial products are sold as Cartilate, Cartilade, BeneFin, AE-941, U-995, Neovastat, Better Shark MC and numerous other brand names.
Cartilage is part of the skeletal system composed of elastic, translucent tissue. Sharks’ skeletal structure is not made of bones but of cartilage. Shark cartilage is obtained from the spiny dogfish shark Squalus acanthias and the hammered shark Sphyrna lewini and is available in either capsule or powder form. Shark cartilage products contain glycoproteins, such as phyrastitin 1 and 2.
Administration is usually either orally in capsule form or rectally by enemas of shark cartilage mixed with sterile water or by subcutaneous injection but is not normally applied intravenously. From clinical studies we know that for refractory metastatic renal cell carcinoma, a specific water-soluble shark cartilage extract, AE-941 (Neovastat), 60 to 240 mL per day has been used.1,2 For the treatment of solid tumors, 30 to 240 mL daily has been used.3 For cutaneous Kaposi’s Sarcoma, shark cartilage 3,750 to 4,500 mg per day has been used.4 Commercial products typically suggest doses ranging from 500 mg to 4.5g, given in two to six divided doses daily.5
In 1963 it was discovered that tumour growth was partly dependant upon angiogenesis.6 William Lane published a book in 1992 entitled Sharks Don’t Get Cancer.7 The claim is incorrect – sharks can get cancer of their cartilage.8,9 Numerous manufacturers offer commercial preparations available as food supplements, sold without restriction, through various outlets. In 1995, over 40 brands were on the market.
In 2000 Lane was prohibited by the Federal Trade Commission from claiming that “BeneFin or any other shark cartilage product prevents, treats or cures cancer”, until he can provide substantial evidence to support this claim. Since shark cartilage has been promoted as a cancer cure, there has been a measurable decline in shark populations.
It is claimed that a protein in shark cartilage can shrink tumour size, slow or stop the growth of cancerous cells and help reverse bone disease such as osteoporosis.7,10 Providers claim that shark cartilage is effective in cancer because of anti-angiogenic properties. Shark cartilage is also claimed to have antitumor, antioxidant, anti-inflammatory and anti-atherogenic actions, although these putative actions are so far poorly supported by credible clinical research.
Angiogenesis enables new blood vessels and, consequently, tumours to grow. All cartilage, including human, contains anti-angiogenic factors. When shark cartilage is taken orally, they are being digested rather than absorbed into the bloodstream. Therefore no effects after oral administration should be expected.
Shark cartilage contains inhibitors of tumour angiogenesis 11-13,34 and immune modulators 14 and may have cytotoxic activity in vitro.35 The polypeptides identified included acidic and basic fibroblast growth factor, angiogenin and transforming growth factors alpha and beta.15 Many of the formulations of commercially available shark cartilage contain little or no anti-angiogenic activity. Furthermore, not all cancers are affected by anti-angiogenic factors. Reliable dose-response data and bioavailability studies are not available.
The popularity of shark cartilage seems to have peaked between 1990 and 2000 but more recent data suggest it is still commonly used by cancer patients.16 Reliable prevalence data are not available. In a survey including 100 patients with various types of cancer shark cartilage was among the most commonly used therapies.17 In an earlier survey including 143 advanced cancer patients, 10.7% of respondents were consuming preparations of shark cartilage.18 More recent survey data imply that 7% of lymphoma survivors use shark cartilage preparations.36 An article in a non-peer-reviewed magazine reports that shark cartilage is a $5 billion-a-year business, with pills and powders sold in health food shops to more than 25.000 people every year.19
Shark cartilage products are marketed as dietary supplements and therefore are not submitted to medicines regulation. Pre-market evaluation and approval by the US Food and Drug Administration (FDA) are not required for dietary supplements. The FDA has not approved of the use of cartilage as a treatment for cancer or any other medical condition. Providers of dietary supplements are not legally permitted to make any claims on the packages of their products for preventing or curing any disease. In practice, such claims are, however, often made via books, websites etc.
A typical course of shark cartilage costs approximately 525 Euros per month and the cost for approximately 100 capsules is approximately 33 Euros.9 The daily cost would be approximately 30 Euros ($40).
Most recent update and revision in November 2011 by Edzard Ernst.
Fully revised and updated in April 2010 by Edzard Ernst.
Summary first published in September 2005, authored by Edzard Ernst.