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Bioidentical Progesterone
Studies,Opinions and Bias About
Safety and Effectiveness

Do you have a an experience to share about using bioidentical progesterone cream...or, a question about getting started with it? Please share your thoughts here In regards to progesterone cream...

What do Proponents and Critics Say about the use of
Bioidentical vs Synthetic Progesterone?

Progesterone Molecule

It's not hard to find statements on the web about the lack of evidence on natural progesterone's safety and effectiveness. What's harder to find, but still very available, is evidence that there have been studies, enough to begin to draw some conclusions. So why are there still so many critics of bioidentical hormones?

Some of these critics say,

“People promoting the use of bioidentical progesterone and other bioidentical hormones stand to gain financially”

This is true, however,

Fugh-Berman, McDonald, Bell, Bethards & Scialli (2011) reviewed 50 articles published in the four years following the Women's Health Initiative study (the study that was stopped early due to findings of increased risk for breast cancer, blood clots, stroke and heart disease for women on HRT) for bias and found that,

“Although most of the articles were scientifically accurate, common themes in the 50 articles included arguments that clinical trial results should not guide treatment for individuals, and suggestions that the risks associated with hormone therapy have been exaggerated and that the benefits of hormone therapy have been, or will be, proven.”

Fugh-Berman et al (2011) also stated, “Articles promoting the use of menopausal hormone therapy were 2.41 times (95% confidence interval 1.49–4.93) as likely to have been authored by authors with conflicts of interest as by authors without conflicts of interest.”

In other words, people promoting the use of non-bioidentical hormones, in many cases, also stand to gain financially.

Safety and Effectiveness
The Arguments for and against Bioidentical Progesterone

“They're not proven safe or effective”

There are hundreds of studies on bioidentical hormones. They have been used in Europe for the last fifty years.

According to Schwarz, Holtorf & Brownstein (2009), “There are 25 years of scientific research with hundreds of studies in the U.S. and Europe that have demonstrated that bioidentical hormones, estradiol and micronized progesterone, are equally or more effective than synthetics -- and safer.”

Moskowitz (2006), in her review of 138 articles on hormones, bioidentical and non-bioidentical, states, “[the author] concludes there is currently sufficient evidence to support their [bioidentical hormones] preferred use over that of their synthetic cousins.”

L'Ermite, Simoncini, Fuller & Genazzani (2008) write, “in specific clinical settings the choice of the transdermal route of administration of estrogens and the use of natural progesterone might offer significant benefits and added safety.”

“You don't know how much is being absorbed when you use bioidentical progesterone cream”

“Over the counter creams should be avoided because they don't contain enough progesterone to be effective”

From Moskowitz (2006): “A study by Hermann et al compared 80mg progesterone daily via a topical cream (Pro-Gest) [an over the counter cream] to 200mg oral micronized progesterone (OMP) as Prometrium daily and found no difference between two products with respect to steady-state blood levels of progesterone as measured by area under the curve (AUC).”

“Oral progesterone is more predictable in terms of absorption”

“Oral micronized progesterone also exhibited substantial variability in absorption among individuals. In one study, maximum serum concentration ranged from 15.72 – 625.98 ng/mL, following a single 300mg dose; the authors also noted that absorption increased with age.” (Moskowitz, 2006).

“Compound Pharmacies Are Not FDA-Regulated”

This argument states that FDA regulation assures uniformity of quality and quantity of the product.

It is true that these pharmacies are not FDA-regulated, they are licensed and regulated by state boards, and their compounds are FDA-regulated, according to the International Academy of Compounding Pharmacists.

Progesterone Terms and Benefits

Progesterone is a hormone produced by women. Progesterone levels are high during the second half of a monthly cycle.

Progesterone is often referred to as the pregnancy hormone, because one of it's main functions is to prepare the uterus for pregnancy.

Progesterone is calming to the nervous system, relieving anxiety and insomnia.

Progesterone is usually the first female hormone to begin declining in perimenopause.

Because progesterone and estrogen work in harmony, the declining progesterone creates an estrogen-dominance situation, where estrogen has too much power in your body.

For symptoms relating to this imbalance of hormones, see symptoms of low estrogen,symptoms of too much estrogen, and symptoms of low progesterone

For a more general discussion on biodentical hormones, see bioidentical hormone therapy

Synthetic, “Natural,” Bioidentical:
What do these terms really mean?

First of all, all hormones except those made by your body are synthetic. All hormones are made in a lab.

Bioidentical describes the structure of the molecule of the hormone. It is thought that a molecule shaped the same way as your human molecules would have safer and more effective actions in your body than one that is shaped like a nonhuman molecule. Also called natural progesterone cream.

In over the counter creams, the ingredient must say progesterone (USP). USP stands for United States Pharmacopeia – the official group that sets standards for prescription and over-the-counter medicines, dietary supplements and other health care products made and sold in the US.

If the label on your product says USP progesterone, that means it meets those standards.

Progestin describes a type of progesterone that is not the same molecular structure as the one your body makes. Provera is a synthetic progestin (medroxyprogesterone acetate), and can have many side effects.

Progestogen could refer to either progestin or bioidentical. Progesterone is also used to refer to either progestin or bioidentical.

And just to be sure that you are thoroughly confused, proponents of bioidentical progesterone often refer to it as natural progesterone, and critics of bioidenticals will refer to progestins as natural progesterone!

Oh yes, and then there's the wild yam confusion. Wild yam is not progesterone, does not contain progesterone, and cannot help your body make progesterone.

If you want to take progesterone, you are looking for bioidentical progesterone, period. It may or may not be made from wild yams.

Your body cannot make progesterone from diosgenin, or any plant that contains it. So you can use all the wild yam or diosgenin you want; but it will not create the same effect as bioidentical progesterone.

Benefits of Bioidentical Progesterone Cream

The thinking behind using bioidentical progesterone cream is to help balance the hormones in your body. Progesterone has many functions, and it is the relative dominance of estrogen, due to environmental factors, as well as the fact that your progesterone levels drop much more in menopause than your estrogen levels do, that cause the problems.

Some signs of estrogen dominance are: depression with anxiety or agitation, dry eyes, fatigue, headaches, foggy thinking, fat gain, especially around abdomen, hips and thighs, irritability, insomnia and memory loss.

Use of progesterone cream may help with mood swings, headaches, bloating, fatigue, insomnia, hot flashes, and low thyroid.

Side Effects of Progesterone Cream

The only side effects mentioned by doctors using this therapy are sleepiness if you use too much, and incidences of having elevated levels of the hormone after using the cream for awhile. This can be avoided by having your levels tested and going off the cream as necessary to restore normal levels or possibly by using lower dose creams.

When I first starting using the cream, it felt so good I couldn't believe I'd waited so long to try it – it was just right for my body at that time. Later on (after a couple of years), I just naturally wanted to taper off – it didn't feel good anymore.

How to use Bioidentical Progesterone Cream

The cream is used for about two weeks per month if you are in pre-menopause, and for about three weeks per month after menopause. The cream can be applied to the face, neck, inside of arms, breasts, back of knees. Rotate where you use the cream from day to day to assure maximum absorption.

For more specific information about progesterone dosage, see How to Use Progesterone Cream

Natural Alternatives to Bioidentical Progesterone

There are other natural alternatives for hormone balance and menopausal symptoms. See maca, herbal progesterone, and herbal estrogen for herbs that can help balance hormones.

Also see soy and menopause for information on the safety and effectiveness of soy supplements.


Fugh-Berman, A., McDonald, C.P., Bell, A.M., Bethards, E.C., & Scialli, A.R. (2011). Promotional tone in reviews of menopausal hormone therapy after the Women's Health Initiative: An analysis of published articles. PLoS Med 8(3): e1000425. doi:10.1371/journal.pmed.1000425

L'Ermite, M., Simoncini, T., Fuller, S., & Genazzani, A.R. (2008). Could transdermal estradiol + progesterone be a safer postmenopausal HRT? A review. Maturitas. 60, 185 – 201. Retrieved from Science Direct.

Moskowitz, D. (2006). A comprehensive review of the safety and efficacy of bioidentical hormones for the management of menopause and related health risks. Alternative Medicine Review. Volume 11, Number 3, 2006.

Schwartz, E., Holtorf, K., & Brownstein, D., (2009, March 16). The truth about hormone therapy. The Wall Street Journal. Retrieved November 27, 2011 from http://online.wsj.com/article/SB123717056802137143.html

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