How Progesterone Is Beneficial – Facts, Not Fiction

Women from puberty to post menopause use bioidentical hormones and know the benefits, and here two private GP’s with many years experience give their views.


Comment by Dame Dr Shirley Bond DCmdrSOStj MB BS LRCP MRCS FFARCS

As a private GP who has been prescribing progesterone for over 30 years, Dr Shirley Bond worked with the late Dr John Lee – the pioneer of bioidentical progesterone usage – and has seen the benefits to her patients. So why is it still being dismissed by those who should know better? Here she gives her views on using bioidentical hormones.

Before using natural progesterone I researched it and its physiological effects fully. I am increasingly frustrated by the increase in anti-progesterone literature especially when the view is supported by incorrect statements. The most recent one I have come across is in a book by Dr Marilyn Glenville. While I respect her as a nutritionist, I feel it necessary to say she is not a medical doctor but has a PhD in nutrition which entitles her to use the prefix Dr.

Synthetic progesterone does not exist

There are no such substances as synthetic progesterones – they are progestins/progestogens and are completely different from progesterone which is a naturally occurring hormone. It can be synthesised in a lab from soya or yam and the chemical that results from this is identical in its chemical and molecular structure to the naturally occurring hormone. This is why the body recognises it as the same as the progesterone naturally produced in a woman’s own body.

When progestogens are synthesised in a lab what results is a completely different chemical molecule. This has one or two actions in the body similar to progesterone – but has many that progesterone does not and which can, and do, cause problems.

Progesterone can be taken by mouth, hence the existence of the licensed form known as Utrogestan. A higher dose needs to be given in this way as some is removed by the liver because it is a naturally occurring hormone. When absorbed via the skin it does indeed go directly to the peripheral blood stream but then goes to the liver where some is removed.

Progesterone and breast cancer

There is much evidence that supports the view that oestrogen is the hormone that induces cancerous changes in breast tissue. Interestingly it is also well documented that this effect is increased when the oestrogen is combined with progestogens as in traditional HRT. If oestrogen is combined with progesterone, not progestogens, this cancer producing effect of oestrogen seems to be reduced although there is not so much research on this available as yet.

It is true that most breast cancers with a high number of oestrogen positive receptors also have a high number of progesterone positive receptors. It has been suggested that this could be a natural response of the body to reduce the oestrogen effect.

Regarding these receptors what is so frequently forgotten is that hormone receptors are very specific in the way in which they respond to hormones. They can only react as they are designed to react. The effect of oestrogen on receptors in breast tissue is to increase the multiplication of cells. If this multiplication over reacts in any tissue cancerous cells develop. The effect of progesterone on receptors in breast tissue is to encourage maturation into normal cells not cancerous cells.

Thus if a patient has progesterone positive receptors the use of progesterone is beneficial.

While progesterone may increase blood vessel formation, there is no evidence that this increases cancer cells. If anything it should help the body’s natural response to cancer cells. We form cancerous cells in our body all the time but if our immune system and blood supply to tissues is good, then specific cells destroy these cancerous cells!

The research into progesterone and osteoporosis was done many years ago and the trial was badly designed. A group of women were divided into group A and B. Group A was given progesterone for 18 months followed by placebo for 18 months and the reverse was done to groupB. 18 months isn’t long enough for a significant change in bone density no matter what treatment is used, therefore a positive result could not have been shown.

I have used progesterone for osteoporosis, for myself and my patients, and together with correct supplementation it works.


Hormones are powerful substances and should only be used as a response to specific symptoms or conditions that they will benefit and preferably supervised by a doctor experienced in that field.

However bioidentical hormones by their very nature must be better and safer than chemical substitutes that mimic the action of natural hormones, but without the same benefits, and to which the body cannot respond normally.

Comment by Dr Tony Coope M.B; Ch.B; D.Obst.R.C.O.G

Dr Tony Coope has over twenty years experience in General Practice, prior to which he spent four years as a hospital doctor, covering the specialities of medicine, surgery, paediatrics, geriatrics and emergency/trauma medicine.

He now works as a private GP with an Integrated Medical approach including the use of nutritional supplements, bio-identical hormones, botanicals and the use of sound and monochromatic light in healing.

Much of what is written about progesterone in the media, including misunderstandings by both doctors and therapists, is a complete distortion of the truth. In the last two decades of practice I have been aware of only one woman who has developed breast cancer while on progesterone, and there were several other factors involved including sporadic use of progesterone cream. My observation supports the view that progesterone receptors on cancer cells are a good thing, an opportunity to slow down their proliferation and even to help prevent recurrence, – in other words it performs the same the role as tamoxifen but without the side effects.

The fact that the placenta in pregnancy raises progesterone levels by as much as twenty to fifty times the norm tells us something about that hormone’s safety during this very sensitive time in the development of the baby. If it was anything but positive, nature would never be this careless. To spread confusion and alarm in this way about bioidentical hormones is unacceptable when there is so much that is known about their benefits to women in all areas of hormone health.

More information:

The late Dr John Lee used progesterone extensively in his practice and wrote and lectured worldwide on the subject. His books are a good place to start for an authoritative and experienced view of the beneficial effect of bioidentical hormones. His most famous is ‘What Your Doctor May Not Tell You About Menopause’ but he wrote others concerning perimenopause and cancer.