Progesterone or Progestin-Does it Matter?

Tomatoes, no matter how they’re pronounced or what side of the pond you’re from, are essentially the same. But Progestins and Progesterone are most definitely different, even though they’re often talked about as if they were the same and that’s a problem. Progestins are synthetic. Progesterone is not. And they act very differently in our bodies.

A few weeks ago, I walked you through the three different types of estrogens our bodies make and their distinct roles. If you missed that very important post, click here to view. It’s important to understand the differences between these estrogens AND progestins vs progesterone in order to begin to understand the controversary that surrounds hormone replacement therapy (HRT).

This is fundamental information that I encourage every woman learn to become her own advocate as a perimenopausal and/or postmenopausal woman and in the world of HRT.

Pro-je-stens or Pro-je-ste-rone

Why A Name Matters

 All through a woman’s life, estrogen usually gets most of the attention and top billing when we’re talking about balancing hormones, perimenopause and menopause. But progesterone is just as important as estrogen. Progesterone is the yin of estrogen. It’s our calming hormone. It is an anti-inflammatory and anti-growth hormone. 

Unfortunately, progesterones, as a group, were given a bad rap with the Woman’s Health Initiative (WHI) study. The study that set Hormone Replacement Therapy aka HRT on its heels 22 years ago. They used Progestins, not Progesterone in the study AND I’ll show you why this matters!

Let’s unpack this a bit. 

First off, progestins do not naturally occur in the human body and the chemical structure actually looks more like testosterone than progesterone. They began to be widely used in the early 1950’s and were the only form of progesterone available until the 1980’s when something called body-identical/micronized progesterone was introduced.

Progestins are the form of hormone used in the BC pill, implants, and hormonal IUDs and they come with a warning. They can cause blood clots, heart attacks and strokes. Taken orally, they can also cause a change in the microbiome, nutrient depletion of vitamins and minerals, reduce libido, cause weight gain, and depression. 

Below is a table that clearly shows the difference between progestins and progesterone.

As you can see, they pretty much work in opposite ways. 

Since there are obvious and crucial differences between progestins and progesterone, it’s super important to know what form was used when reading published data on hormone replacement therapy, listening to the media, and when tapping into professional groups. Unfortunately, these two forms of ‘progesterones’ are often talked about as if they were the same, so sometimes it’s hard to know what is being referred to. It’s tricky.

This is also important when discussing hormones with your doctor. There are still many doctors who are of the mindset that progesterone causes cancer and heart disease and will be hesitant to prescribe OR they will unknowingly prescribe a progestin. (That just happened to a client this week) They haven’t been taught the distinction between the two forms. And maybe it’s not their fault.

As I mentioned, when talking about estrogens, teaching about hormone replacement in medical school pretty much came to a halt in 2002 with the, not-so-well reviewed, results of the WHI study. So that means the majority of doctors 50 years and younger have not received much training in this arena.

I began this piece by saying that progesterone is the yin of estrogen. It works as a counterbalance to estrogen in all parts of the body including:
  • The UTERUS, where progesterone thins the lining while estrogen thickens it.
  • The BRAIN, where progesterone is calming while estrogen is stimulation
  • The BREASTS, where progesterone helps to slow cell division, while estrogen increases cell division.
  • SLEEP!!! Helps with GABA and serotonin receptors
  • The BONES, where progesterone helps to stimulate the bone building cells called osteoblasts.
It’s a wonderful modulator and equalizer.

Many doctors do not feel it’s necessary to include micronized progesterone in their HRT protocol if a woman has had a hysterectomy, but as I’ve just pointed out, it does more than just thin the uterine lining, so in my opinion, it’s beneficial to include, uterus or not.

Over a woman’s lifetime, until menopause, she receives the protective effects from both estrogen and progesterone produced during her monthly cycles.

The use of oral birth control pills (progestins) stops this whole beautiful dance between estrogen and progesterone and actually takes away this protective process. While I’m all for stopping unwanted pregnancy, I’m not so much in favor of the way BC pills are prescribed to young women, to help with acne, ‘regulating periods’, and reducing PMS. The pill, used in this way, is  just masking the underlying problem(s). And it’s all too often given without a clear disclosure of the risks aka a full informed consent.

I know, I’ve digressed a bit here but there’s so much I want to say and all at once!!! The important thing to remember is, the name DOES matter because these two different types of progesterone behave so differently, with different outcomes and consequences.

I welcome any comments or questions! Be well!

Cindy D

Please remember that anything written here is for informational purposes only. Nothing here is to replace the care or recommendations by your health care provider.

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