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Montana Integrative Medicine :: Bozeman, MT

Natural Versus Synthetic Hormone Replacement Therapy
By Dr. Charlotte Massey, ND, LAc

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When women consider hormone replacement therapy, most women are familiar with the terms natural and synthetic and typically think only of estrogen and progesterone.  Relative to hormone replacement therapy, what does “natural” really mean?

Clarification of the term natural in the context of hormone replacement therapy is a very important distinction for any woman considering hormone therapy to understand.  In my experience, as a naturopathic doctor, patients often equate natural with healthy and safe and therefore they want the most “natural” approach available.   Often what women really mean when they inquire about natural hormone replacement are the hormones that are made from plants as compared to the hormones made from pregnant mare’s urine which are considered synthetic, such as Premarin™.  The hormones that are made from plants and considered to be “natural” are termed bio-identical.

The hormones that can be used in bioidentical hormone replacement therapy are made from plants and consist of the same hormones our bodies make: estrone, estradiol, estriol, progesterone, dehydroepiandrosterone (DHEA), and testosterone. These hormones are made from either beta-sitosterol extracted from the soybean or from diosgenin extracted from Mexican wild yam root.  The hormone that is produced is biochemically identical to the same hormone our body makes, hence the term bioidentical.  When referring to hormone replacement therapy, I prefer the term bioidentical to natural, as it is a more accurate description of the type of hormone therapy.

Bioidentical hormone replacement is available in customized doses from compounding pharmacies made in the form of cream, capsules, troches or sublingual drops.  Certain bioidentical hormones are also available through conventional pharmacies that have been manufactured by a pharmaceutical company such as estradiol as the Vivelle-Dot™ and progesterone as Prometrium™.  Even though pharmaceutical companies manufacture the latter, the hormone delivered is bioidentical.  The Vivelle-Dot™ contains estradiol, a bioidentical hormone therapy.  It is made from a plant source and is biochemically identical to the estradiol made by our bodies.  The advantage of prescriptive compounded hormones is that there is a greater diversity of doses and greater combinations of the different hormones available.  Ultimately it is a matter of which type of delivery system works best, meaning which one does the patient get the most benefit from.  Some women simply don’t absorb the cream well so therefore she may receive greater benefit from the Vivelle-Dot™ a patch with a patented delivery system to aid the absorption of estradiol.

So how do bio-identical hormones differ from synthetic? You may recognize synthetic hormones best by their names, such as Premarin™ and Prempro™.  Premarin™ consists of conjugated equine estrogens (CEEs) and Prempro™ contains conjugated equine estrogens (CEEs) plus medroxyprogesterone acetate (MPA), a synthetic progestin.  Conjugated equine estrogens are derived from pregnant mares’ urine.  Within Premarin™ there are about 10 different types of synthetic estrogens, none of which match the estrogen made by the human body.  Premarin™ has also been shown to contain about 200 additional ingredients, most of which are foreign to humans and their exact actions within the body are unknown. 

MPA is a synthetic progestin that has progesterone-like activity in the body; however, it is not the same as bio-identical progesterone and it has been shown to have increased adverse effects on the cardiovascular system.  An additional disadvantage for synthetic hormones is that they are only available in standardized doses manufactured by pharmaceutical companies, which means that the doses cannot be customized to meet an individual’s unique needs.   Also, since synthetic hormones do not match what the body makes, their levels cannot be measured by laboratory testing whereas the levels of bio-identical hormone replacement can be measured by both blood and saliva tests.  Measuring the amount of hormone replacement provides guidance to ensure that the lowest effective dose is being used as treatment.

There are risks associated with hormone replacement therapy, both synthetic and bioidentical. I recommend that women be screened by a qualified physician for their personal risk factors based on their health history and their family health history.  I also recommend that women be as informed as they can be about both the risks and benefits of hormone replacement.  If hormone therapy is a safe option, it can be used to treat moderate to severe symptoms of menopause. If a woman is already taking synthetic hormone replacement, she can safely be switched over to bioidentical hormone therapy.  Within my practice at Montana Integrative Medicine I work with bioidentical hormone therapies when treating women with menopausal symptoms.