Bioidentical estrogens and micronized progesterone are made into a range of products, many of which are FDA-approved and available with a prescription at your local drugstore (see chart, “FDA-approved hormones for menopausal symptoms”). Commercially available bioidentical estradiol comes in various presentations and forms, such as including pill, patch, cream, and various vaginal preparations. For progesterone it is micronized and comes in a capsule or as a vaginal gel.
|FDA-approved hormones for menopausal symptoms|
|Conjugated equine estrogens (CEE)/
pregnant mares’ urine
|Synthetic conjugated estrogens/plants||Cenestin, Enjuvia||Pill||No|
|Alora, Climara, Esclim, Estraderm, Vivelle, others||Patch||Yes|
|Estropipate (modified estrone)/plants||Ortho-Est, Ogen, others||Pill||No|
|Estradiol acetate||Femring||Vaginal ring||Yes|
|Estradiol hemihydrate||Vagifem||Vaginal tablet+||Yes|
|Progestins, micronized progesterone|
|Medroxyprogesterone acetate (MPA)||Amen, Cycrin, Provera||Pill||No|
|Micronized* progesterone USP||Prometrium||Pill||Yes|
|Prochieve 4%||Vaginal gel||Yes|
|Norethindrone||Micronor, Nor-QD, others||Pill||No|
|Norethindrone acetate||Aygestin, others||Pill||No|
|CEE and MPA||Premphase, Prempro||Pill||No|
|Ethinyl estradiol and norethindrone acetate||Femhrt||Pill||No|
|17 beta-estradiol and norethindrone acetate||Activella||Pill||No|
|17 beta-estradiol and norgestimate||Prefest||Pill||No++|
|17 beta-estradiol and levonorgestrel||Climara Pro||Patch||No++|
|*Particles are made smaller for better absorption.
**Bioidentical estradiol until ingested and converted in the liver to estrone.
+For vaginal symptoms only.
++The estradiol is bioidentical but not the progestin.
Bioidentical estradiol in pill form is converted in the liver to estrone, a weaker bioidentical estrogen. In order to get the maximum benefit of estradiol before it get metabolized in the liver, the so called first pass metabolism, the estradiol is best given non enterically, such as given in cream form and absorbed through the skin and NOT the GUT. When given in a patch, it enters the bloodstream as bioidentical estradiol. Creams, gels, and lotions applied to the legs or arms can also deliver bioidentical estradiol directly to the bloodstream, although it’s uncertain how much is absorbed.
Studies have shown that the natural hormone or bioidentical hormone can help to relieve hot flashes and vaginal dryness, but as yet, few large studies have investigated the differences among the various hormones and methods of administration. More research is needed to further understand these differences and compare the risks and benefits.
Women taking bioidentical estrogen who have a uterus must still take an FDA-approved progestin or micronized progesterone to prevent endometrial cancer. It serve to prevent unopposed hypertrophy of the uterine lining, much the same in the second half of the menstrual cycle where its level increased. So-called natural, plant-derived progesterone creams sold over the counter contain too little of the hormone to be effective. And yam extract creams don’t help because your body cannot convert them into progesterone.