AE-941, Arthrovas™, cartilage, Cephaloscyllium ventriosum, chondroitin sulfate, chondrosine, Haifischknorpel (German), Houtsmuller diet, Mustelus californicus, Neoretna, Neovastat®, octasaccharides, polar shark cartilage, Psovascar™, shark, shark fin soup, smooth-hound shark, Sphyrna lewini (hammerhead shark), squalamine, Squalus acanthias (spiny dogfish shark), swell shark, U-955.
Note: The product Catrix® is made from cow cartilage, not from shark cartilage.
Shark cartilage is one of the most popular supplements in the United States, with over 40 brand name products sold in 1995 alone. Primarily used for cancer, its use became popular in the 1980s after several poor-quality studies reported "miracle" cancer cures.
Laboratory research and animal studies of shark cartilage or the shark cartilage derivative product AE-941 (Neovastat®) have demonstrated some anti-cancer (anti-angiogenic) and anti-inflammatory properties. However, there is currently not enough reliable human evidence to recommend for or against shark cartilage for any condition. There are several ongoing cancer studies. Many trials are supported by manufacturers of shark cartilage products, which raises questions about impartiality.
Commercial shark cartilage is primarily composed of chondroitin sulfate (a type of glycosaminoglycan), which is further broken down in the body into glucosamine and other end products. Although chondroitin and glucosamine have been extensively studied for osteoarthritis, there is a lack of evidence supporting the use of unprocessed shark cartilage preparations for this condition. Shark cartilage also contains calcium. Manufacturers sometimes promote its use for calcium supplementation.
Shark cartilage supplements at common doses can cost as much as $700-1,000 per month.
Chondroitin sulfate, a component of shark cartilage, has been shown to benefit patients with osteoarthritis. However, the concentrations of chondroitin in shark cartilage products may be too small to be helpful. The ability of shark cartilage to block new blood vessel growth or reduce inflammation is proposed to be helpful in rheumatoid arthritis. However, there is limited research in these areas, and more studies are needed before a strong recommendation can be made.
For several decades, shark cartilage has been proposed as a cancer treatment. Studies have shown shark cartilage or the shark cartilage product AE-941 (Neovastat®) to block the growth of new blood vessels, a process called "anti-angiogenesis," which is believed to play a role in controlling the growth of some tumors. There have also been several reports of successful treatments of end-stage cancer patients with shark cartilage, but these have not been well designed or included reliable comparisons to accepted treatments.
Many studies have been supported by shark cartilage product manufacturers, which may influence the results. In the United States, shark cartilage products cannot claim to cure cancer, and the U.S. Food and Drug Administration (FDA) has sent warning letters to companies not to promote products in this way. Without further evidence from well-designed human trials, it remains unclear if shark cartilage is of any benefit in cancer and patients are advised to check with their doctor and pharmacist before taking shark cartilage.
It is proposed that shark cartilage or the shark cartilage product AE-941 (Neovastat®) may be helpful in patients with macular degeneration. A small amount of research suggests possible benefits, but more study is needed before a recommendation can be made.
Based on laboratory studies, shark cartilage may reduce inflammation. However, it is unclear if shark cartilage is a safe or helpful treatment for pain in humans.
Shark cartilage products have been tested by mouth or on the skin in people with psoriasis. However, no clear benefits have been shown. More research is needed before a conclusion can be drawn.
Doses of 0.2 to 2.0 grams per kilogram of body weight per day, taken by mouth in two to three divided doses, have been studied.
80 to 100 grams of ground shark cartilage extract has been taken by mouth daily, divided into two to four doses. Doses of the shark cartilage derivative AE-941 (Neovastat®), available in clinical trials, have ranged from 30 to 240 milliliters per day taken by mouth or 20 milligrams per kilogram taken twice daily. Rectal doses of 15 grams per day or 0.5 to 1.0 grams per kilogram of body weight per day in two to three divided doses (prepared as an enema) have also been studied.
Creams applied to the skin with 5% to 30% shark cartilage are available and have been recommended by some practitioners for the treatment of psoriasis alone or with shark cartilage by mouth, for four to six weeks. Studies have used 5% to 10% preparations applied daily.
Shark cartilage is not recommended in children due to a lack of scientific study and a theoretical risk of blocking blood vessel growth. There is one report of a nine year-old child with a brain tumor treated with shark cartilage who died four months later.
Allergic reactions to shark cartilage or to any of its ingredients are possible, although there is limited human information in this area. Caution should be used in patients with a sulfur allergy since products may be sulfated.
A limited amount of published research suggests that shark cartilage is well tolerated in most people at recommended doses. The most common adverse effects reported are mild-to-moderate stomach upset and nausea. In several studies, patients stopped taking shark cartilage due to gastrointestinal distress, cramping, or bloating. Liver damage and taste alteration has been reported.
Uncommon side effects reported in studies or historically include confusion, decreased muscle strength, decreased sensation, weakness, dizziness, fatigue, increased or decreased blood sugar levels, and low blood pressure. Shark cartilage products may contain high levels of calcium, which may be harmful to patients with kidney disease, abnormal heart rhythms, a tendency to form kidney stones, and those with cancers that raise calcium levels. In theory, due to the blocking of new blood vessel growth, shark cartilage may be harmful in people with heart disease or narrowed blood vessels of the legs (peripheral vascular disease). In theory, wound healing and recovery from surgery or trauma may be reduced.
One case report implicates inhaled shark cartilage dust in an asthma exacerbation and resulting death of a 38 year-old male.
Shark cartilage is not recommended in pregnant or breastfeeding women. Shark cartilage may block the growth of new blood vessels and drugs with similar properties, such as thalidomide, can cause birth defects. There is limited study of shark cartilage in these areas.
Shark cartilage products may contain high doses of calcium and may cause dangerously high blood calcium levels when taken with drugs known to increase blood calcium. Examples include long-term use of thiazide diuretics such as chlorothiazide (Diuril®) and antacids such as Tums®. In theory, shark cartilage may add to the effects of drugs and experimental agents that block new blood vessel growth. Based on one animal study, the cancer drug cisplatin and shark cartilage may act together against tumors, although there is a lack of reliable human supportive evidence.
Limited evidence suggests that shark cartilage may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare provider. Medication adjustments may be necessary.
Shark cartilage products may contain high doses of calcium and may cause dangerously high calcium levels in the blood when taken with calcium supplements or antacids. Chondroitin sulfate and glucosamine may have additive effects when taken with shark cartilage.
Limited evidence suggests that shark cartilage may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.
Trace elements that are found in shark cartilage in higher amounts than those in other fish or animal bones include iron, zinc, selenium, manganese, copper, molybdenum, titanium, and strontium.
This information is based on a professional level monograph edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): Ernie-Paul Barrette, MD (Case Western Reserve University School of Medicine); Ethan Basch, MD (Memorial Sloan-Kettering Cancer Center); Samuel Basch, MD (Mt. Sinai Medical Center, NY); Steve Bent, MD (University of California, San Francisco); Heather Boon, BScPhm, PhD (University of Toronto); Dawn Costa, BA, BS (Natural Standard Research Collaboration); Paul Hammerness, MD (Harvard Medical School); Jenna Hollenstein, MS, RD (Natural Standard Research Collaboration); Michael Smith, MRPharmS, ND (Canadian College of Naturopathic Medicine); David Sollars MAc, HMC (New England School of Acupuncture); Philippe Szapary, MD (University of Pennsylvania); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Candy Tsourounis, Pharm D (University of California, San Francisco); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).
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Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.