Related Topics: Breast Cancer, Features, Hormones

Breast Cancer And Progesterone

Bioidentical doctors have been saying for years how protective progesterone is for breast cancer. Now research seems to have ‘discovered’ it but are we talking about the same thing?

AnnA Rushton

There are around 55,200 new breast cancer cases in the UK every year, that’s around 150 every day (2014-2016). Breast cancer is a major health concern as it claims the lives of almost 1,000 women a month.

Progestins or progesterone?

For many years researchers such as Dr Ray Peat, bioidentical pioneers such as Dr John Lee and doctors experienced in bioidentical progesterone usage such as Dame Dr Shirley Bond have advocated the use of bioidentical progesterone to help oppose the excess oestrogen that is behind the disease.

Now it seems that medical science has caught up as Cambridge University researchers have shown that ‘progesterone’ slows the growth of tumours.

I agree it absolutely has been shown to be effective in helping women with a history of breast cancer both preventively and after treatment to help with the side effects.

However what concerns me is that they also state that it is an’ inexpensive drug used in contraceptives’, so yet again we have the confusion between the natural hormone progesterone and the synthetic progestin.

They are not the same, progestins have their own side effects and cannot replicate the effects of the natural hormone in the way that bioidentical progesterone can.

Why bioidentical progesterone is effective

The study appears to suggest that progesterone may work in nearly half of the 55,200 cases diagnosed each year when these are oestrogen receptive.  Researcher Jason Carroll said:

‘The results are pretty clear and potentially have direct benefits for many women with breast cancer.’

His research centres on tumours that are fuelled by the hormone oestrogen and in this type of tumour, progesterone ‘talks’ to the oestrogen that is trying to feed the tumour. This stops the cancer from growing as quickly.

The journal Nature has also reported tests on mice with tumours given progesterone at the same time as tamoxifen, a drug widely used after breast cancer surgery, had a dramatic effect.

Cancers treated with the progesterone-tamoxifen combination grew half as quickly as those given tamixofen alone.

Again this is not news to bioidentical doctors like Dr Shirley Bond who has recommended using progesterone alongside Tamoxifen to offset the side effects of the drug, particularly the horrendous hot flushes which are a common result.

What you can do

A simple way to protect yourself from breast cancer risk is to tackle any oestrogen dominance to minimise the risk of breast cancer and this is best done by reducing your risk factors.

Supplementing with bioidentical natural progesterone is a critical first step, as is making sure you are not overweight as that means you will be producing additional oestrogen in your fat cells, particularly after a hysterectomy and at menopause.

As almost 70 per cent of women now survive breast cancer beyond 20 years any advance in treatment is welcome, but don’t ignore the experience of the thousands of women who are already successfully using bioidentical progesterone.

What we need to ensure that it is the real hormone, and not a synthetic progestin, that is being used in any treatment regime.

Helpful information

Good hormone levels are essential to good health, and particularly in the case of all hormonal cancers, and it is progesterone that is the vital hormone to oppose excess oestrogen.

The book ‘What Your Doctor May Not Tell You About Breast Cancer’ by John Lee MD is available as a Kindle or paperback.

Transdermal Creams Confirmed As Best For Hormone Use


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Please feel free to discuss this article in the comments section below, but note that the author cannot respond to queries made there.
Comments 8
Sorted by:  Date | Recommended
AnnA Rushton | 8:57 am, February 16th, 2018

From our website Bernadette at

Bernadette | 8:40 pm, February 14th, 2018

Hi I am on tamoxifen for breast cancer where do I get biodentical progesterone..

Elaine | 3:32 am, January 4th, 2018

I have recently been diagnosed with ductal carcinoma in situ which has been caught early and being removed next week before it spreads .I used to take menapause plus boots own brand but have stopped through the worry it may have helped to cause the cancer cells forming I am now suffering night sweats and really want to take something that stops this but won’t be a threat to breast cancer please help getting desperate ..

AnnA Rushton | 5:27 pm, October 31st, 2017

Dawn we do know of some GP’s prescribing Serenity on the NHS as it is classed as a natural medicine, but having said that there are not many GP’s prescribing it. It will depend on the attitude of the individual doctor and their practice guidelines. As the action of progesterone is to oppose the excess oestrogen associated with breast cancer it can be used alongside or after Tamoxifen usage.

Dawn Croft | 9:01 pm, October 30th, 2017

Please can you advise if a GP could prescribe bioidentical progesterone? Or would it be prescribed from a breast care clinic? Also, is the taking of this medication as effective several years after finishing taking tamoxifen?

AnnA Rushton | 10:09 am, August 1st, 2015

You could use a combination cream such as 20-1 vaginally to help Gisella and would help with the sore breasts.

Gisella Mantovani | 12:18 am, July 29th, 2015

I have reoccurrence of bladder infections due. Of manapause been on hrt creams but not happy cause I have breast cancer history in my family I have stop taking the cream cause my infections still come back plus my breast were getting tender so went to my go & he suggested to go on low dose suppository but iam very against Taking. These hrt products so can u suggest me what natural hrt creams I try for this problem thanku

jr | 8:13 pm, July 16th, 2015

This is more evidence that the WHI was not the definitive trial assessing HRT and breast cancer risk. WHI utilized Premarin and Provera (Prempro) or Premarin alone. Prempro increased breast cancer and Premarin alone decreased it. Researchers took these findings to mean that estrogen *prevents* cancer and progesterONE causes it. Both are incorrect. Premarin is horse estrogen and WEAKER than human estradiol, so it may have been acting like tamoxifen in the WHI women. Provera, on the other hand, has consistently been shown to have different effects on cell growth than natural progesterone. E3N, from France, is a better study because it shows that estradiol alone or combined with progestIN causes breast cancer, but estradiol combined with micronized progesterone was neutral.

Hopefully, this new research will be the beginning of a paradigm shift.

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