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Shark cartilage and cancer

Shark cartilage is cartilage taken from spiny dogfish sharks and hammerhead sharks and made into a powder. You can buy it as a food or dietary supplement.

Several years ago, a doctor published two books that claimed that sharks don’t get cancer and that shark cartilage could cure cancer. This is not true and sharks can get cancer. But many people with cancer still believe that shark cartilage may control their cancer or cure them, even though there is no scientific evidence for this.

Brand names for shark cartilage include Carticin, Cartilade and BeneFin. Some people use these as an alternative cancer therapy. You can find information about why people with cancer use alternative therapies in our complementary and alternative therapies section.

An extract from shark cartilage called AE-941 (Neovastat) has been developed and is being researched as a cancer treatment. You take AE-941 as a liquid that you drink.


How you take shark cartilage

Shark cartilage comes in various forms. The most common type is capsules that you swallow. You can also take it

  • As a powder or a liquid that you swallow
  • As an enema (into the back passage – rectum)
  • As an injection under the skin

Most researchers agree that the protein molecules in shark cartilage powders are too big for the digestive system to absorb. So shark cartilage that you swallow is not likely to be absorbed into the body.

In the UK, shark cartilage is sold as a food supplement and not a drug. You can buy it over the counter in many health food shops. The USA’s Federal Trade Commission found that many over the counter products don’t actually contain much shark cartilage. Unfortunately, we don’t know how much shark cartilage is in the products available in the UK. There is no scientifically proven recommended dose of shark cartilage. Some commercial suppliers suggest 70 grams per day. But shark cartilage contains calcium salts, and some doctors are worried this would mean taking in too much calcium. This could cause serious health problems.


Side effects of shark cartilage

We know from research that shark cartilage can often cause changes in the way you taste things. Other rare side effects include

  • Feeling and being sick
  • Loss of appetite
  • Itching
  • Diarrhoea
  • Constipation
  • Indigestion
  • Dizziness
  • Swelling of hands and feet due to fluid collection
  • Tiredness
  • Low blood pressure
  • A change in blood sugar levels
  • High blood calcium levels

These effects can be serious. In research studies, one patient with diabetes had low blood sugar levels. Another patient had liver problems. Doctors recommend that people with liver disease should not take shark cartilage.


Research into shark cartilage in people with cancer

Researchers have been interested in cartilage as a potential treatment for cancer because cartilage doesn’t contain any blood vessels. Cancers develop blood vessels to supply them with food and oxygen and help them to grow. Some laboratory studies have shown that certain compounds in shark cartilage can block the growth of blood vessels. So in theory this could slow down the growth of cancer cells or stop the cancer growing. But no research has shown that it can do this in humans. Cancer treatment designed to stop the growth of blood vessels is called anti angiogenesis. We have information about other anti angiogenesis treatments in our biological therapy section.

In 1998, an American study tested shark cartilage in 60 patients with advanced cancer, when their treatment was no longer working. The study used the brand called Cartilage, which is a powder.

None of the patients showed a response to treatment with shark cartilage. The study authors found that shark cartilage

  • Didn’t help people with advanced cancer
  • Didn’t improve quality of life for people in the study

A highly purified extract of shark cartilage called Neovastat (AE-941) was tested in a clinical trial in America in 2007 and reported in 2010. Neovastat was given alongside chemotherapy and radiotherapy to people with advanced lung cancer. Everyone in the trial had chemotherapy and radiotherapy. Half the patients also had treatment with Neovastat. The other patients had a placebo pill. The study showed that Neovastat gave few side effects and was safe to take but did not help people to live longer.

In May 2005, The United States National Centre for Complementary and Alternative Medicine (NCCAM) reported on a trial using a brand of shark cartilage called BeneFin. 88 patients with advanced breast or bowel cancer had either standard care or standard care plus Benefin. The study showed that shark cartilage did not improve survival or quality of life.


The cost of shark cartilage

Alternative therapies are usually quite expensive. Before you start taking any alternative therapy, make sure you have thought about the ongoing cost. Shark cartilage capsules sold over the internet can cost about £20 for a box of 100 capsules. Depending on who you buy it from, the recommended dose is between 3 and 12 capsules, 3 times a day. At the highest dose, £20 worth would last less than 3 days.


Internet information about shark cartilage

The internet can make it easy to find information about cancer therapies. But it is important to remember that anyone can write information or advertise health treatments on the internet. There isn’t any regulation, so many people use the internet to make false claims.

Many websites advertise or promote shark cartilage as a cancer treatment. But no reputable scientific cancer organisations support any of them. Some people who promote alternative therapies such as shark cartilage rely on the experiences, or stories, of people who have used them. Be very cautious about believing information you read on the internet. Be very careful about paying to take any type of alternative cancer therapy.

We have a section on searching for information on the internet in our about complementary therapy section.


A word of caution

We don't recommend alternative therapies such as shark cartilage, as there is no scientific or medical evidence to back up the claims made for them. If you have cancer, using unproven methods instead of conventional medical treatment can be very harmful to your health.

Talk to your own specialist about any alternative or complementary therapies that you want to try. Then your doctor will always have the full picture about your care and treatment. It is also very important to find out all you can about the therapy before deciding to use it. We have information about the safety of using complementary and alternative therapies in this section.

We are concerned that people can end up paying a great deal of money for so called cancer cures that don’t work. Some alternative therapies are money making businesses targeting people who are ill and very vulnerable. So it is important to be very careful.


Useful organisations

Some of the organisations listed on our complementary therapy organisations page can give information about shark cartilage.

You can also find information on the following websites.

The Memorial Sloane Kettering Integrative Medicine website has information about many types of herbs and dietary supplements. It also evaluates alternative or unproven cancer therapies.

The American Cancer Society has information about complementary and alternative therapies.

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Updated: 11 January 2013