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Modified citrus pectin (MCP)

Find out about modified citrus pectin.

Modified citrus pectin (MCP) is an alternative therapy. Some websites claim that it can help to stop prostate cancer and melanoma skin cancer from spreading. There is no scientific evidence to back up this claim.

Pectin is found in many fruits, including citrus fruits. It is what we use to make jam set, and is found mostly in the pips and the pith of citrus fruits.

The pectin in modified citrus pectin has been changed to make it easier for the body to take in through the gut.


Alternative therapists claim that pectin may help to stop prostate cancer and melanoma spreading. MCP has been tested in animal studies for these cancers.

In mice, MCP seemed to lower the risk of prostate cancer spread to the lungs. Also in mice, it seemed to result in less melanoma spread to the lungs.

MCP may make it harder for cancer cells to break away and spread in mice but it hasn't yet been shown to affect primary cancers (the original tumour). It has also not shown any activity in fighting cancer in people.

One study in humans tested modified citrus pectin (MCP). This was a small pilot study looking at the effect of MCP on prostate specific antigen (PSA).

Prostate Specific Antigen is a protein produced by prostate cells. It is produced in higher amounts by prostate cancer cells.

The study looked at the time it took for PSA levels to double in men with prostate cancer who had not responded to treatment at all, or whose cancer had begun to grow again after treatment. 

It did seem to take longer for the PSA to double in some of the men on the trial. Researchers decided that more trials with larger numbers of patients will have to be done before we know if MCP is of any use in prostate cancer treatment.

Until such studies are carried out and published, Cancer Research UK will not be able to offer any other view on this substance.

How is it taken?

You take it as a capsule or a powder. The powder needs to be dissolved in liquid and taken on an empty stomach.

Side effects

There is not much information about the side effects of modified citrus pectin. Some reports seem to show that in large quantities it may cause diarrhoea, stomach pains and wind (gas).

Always speak to your doctor if you are thinking of starting to take any alternative or complementary therapy such as MCP.

Last reviewed: 
21 Jul 2015
  • Complementary and alternative medicine use among newly diagnosed prostate cancer patients
    CM McDermott and others
    Supportive care in cancer, 20 (1): 65-73, 2012

  • Memorial Sloan-Kettering Cancer Center information about Pectin
    Accessed on July 21 2015

  • Clinical benefit in patients with advanced solid tumors treated with modified citrus pectin: a prospective pilot study
    M Azemar and others
    Clinical Medical Oncology, 2007, 1: pages 73-80

  • Modified Citrus Pectin - Prostate Cancer, Nutrition, and Dietary Supplements
    National Institutes of Health, USA - accessed March 2015

  • Modified citrus pectin (MCP) increases the prostate-specific antigen doubling time in men with prostate cancer: a phase II pilot study
    BW Guess and others
    Prostate Cancer and Prostatic Diseases, 2003;6(4): pages 301-4


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