What are Progestins, Progestogen & Progesterone?

Confusion arises when one word is regularly used to refer to three different molecules.

As a colleague of Dame Dr Shirley Bond’s for many years, we update each other regularly on hormonal matters of interest.  A recent piece in the Sunday Mail – and repeated in the Daily Mail – made my blood boil. It also make me  want to tear out my hair and bang my head against the wall – not a healthy combination!

I frequently respond to questions from women who tell me they are taking progesterone in their Pill/Coil or HRT – but they are not.  It is not their fault that they believe this as both their doctor and media continue to make this elementary mistake.

They are not the same: it is rather like getting a new key cut which goes into the lock so it fits, but it won’t turn and open the door. Progestogens mimic the action of progesterone, but they are not the same thing.

Excellent Illustration

The reporter in the newspaper said in a piece on the Pill and depression that “those taking the combined Pill – which contains the hormones oestrogen and progestogen (of which progesterone is the most commonly known form).

To say that the natural hormone is a form of a synthetic progestogen/progestin is so topsy turvey I sent it to Dr Bond for her comments, reported below:

Yet again we have an article which confuses progesterone and progestogen.

First of all just look at the chemical structures of these two compounds and it is obvious they are not the same. While they may contain the same atoms the way they are put together is what makes the difference.

An example that explains this more easily is to consider coal and diamond. Both of these are made up of carbon atoms but the molecular structur of the compounds results in completely different substances. So it is with progesterone and progestogen.

Another Excellent Illustration

One of the reasons there is confusion regarding the fact that progesterone is different from progestogen stems from the use of the term progestogens by the medical and pharmaceutical powers.  This arose way back in the 1950s when HRT was being introduced.  Although it was recognised that the natural occurring hormone progesterone was the best hormone to counteract the bad effects of oestrogen, the drug companies were reluctant to include it in their products because it could not be patented.

So, the molecule of progesterone was tinkered with and changed to a form that could be patented.

Although this product now called progestogen prevented the unwanted effect of oestrogen on the uterus, i.e. cancer, it did not have the same effect on other parts of the body as progesterone.

In fact we now know that progestogen increases the cancerous effect of oestrogen on the breast.

It is so important that this confusion is corrected and that accuracy exists.

How can the general public have correct information when those who write articles about progesterone and progestogens fail to check that what they write is correct?