Modified citrus pectin (MCP)

Modified citrus pectin (MCP) is an alternative therapy. There is not enough scientific evidence to say that pectin can treat cancer. 


  • Pectin is a naturally occurring substance (a polysaccharide) found in the peel of citrus fruits.
  • Large quantities may cause diarrhoea, stomach pains and wind.
  • Claims that MCP can treat cancer are not backed up by enough research.

What is modified citrus pectin?

Pectin is in the peel and pulp of citrus fruits - lemons, oranges, grapefruits and apples. It is what we use to make jam set. The pectin in modified citrus pectin has been broken down. This makes it easier for the body to absorb through the gut. 

Why people with cancer use it

Early trials in the laboratory have shown that MCP may have an effect on cancer growth and very early studies showed it had some effect in prostate cancer cells.  

MCP may also stimulate the immune system and lower cholesterol. 

How you have it

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

In large quantities modified citrus pectin may cause diarrhoea, stomach pains and wind (gas).

Research into MCP as a cancer treatment

In 2007 a pilot study gave 5g of modified citrus pectin (MCP) powder dissolved in water to patients with different types of cancer including prostate cancer. They took the treatment 3 times a day for 8 weeks. Following treatment patients reported some improvement in their quality of life, including less fatigue, pain and insomnia. 

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

PSA 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.

How much it costs

Be cautious about believing information or paying for any alternative cancer therapy on the internet. Prices can vary greatly from a few pounds to hundreds of pounds. 

A word of caution

It is understandable that you might want to try anything if you think it may help treat your cancer. It is important to talk with your doctor first before taking an alternative or complementary therapy. 

You could harm your health if you stop your cancer treatment for an unproven treatment. 

Larger studies need to be done to test MCP to see whether it is useful in cancer care. Until further studies are carried out and published, Cancer Research UK will not be able to offer any other view on this substance.

  • 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 August 2022

  • 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 August 2022

  • 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

Last reviewed: 
08 Aug 2022
Next review due: 
08 Aug 2022

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