Bioidentical Hormones

by Christiane Northrup, M.D.


There seems to be a lot of confusion around the definition of “natural” versus “bioidentical versus “synthetic” hormones. One thing to remember when making this distinction is that “bioidentical” refers to the shape of the molecule itself rather than the source of the hormone. By this, I mean that hormones can be marketed as “natural” or “plant-based,” yet not come near to being “bioidentical” to native human female hormones or performing as such in the body. Examples of this are the numerous proprietary HRT options being marketed as “plant-based” and “natural,” as well as purely yam-based creams.

Our bodies are literally swimming in hormones that act somewhat analogous to keys in a lock, or pieces to a puzzle. Though this analogy presents a less than complete picture, it can be helpful toward a basic understanding of their action. The puzzle to which I refer makes up the big picture of who we are as human beings and how we operate. When we take in hormonal replacement therapy that doesn’t fit the original design that our cells have evolved to recognize, the end result simply may not feel or act quite right. Hence all those side effects, ranging from annoying and uncomfortable to downright dangerous.

Many pharmaceutical companies are capitalizing on women’s quest for “natural” hormone replacement therapy by marketing proprietary hormone products that are “plant-based.” Yes, many of these hormonal molecules may have been derived from plant sources, but no, the molecules themselves do not always match those found in human females. Moreover, they are often not effectively converted or used in the body and sometimes have actions that are more deleterious than the symptoms they purport to quell or stave off.

Our hormones are comprised of a solid steroid base (yes—cholesterol!), decorated with “arms,” “legs,” and “tails” pinned on here and there. These attachments are what turn hormones into specialized molecules, allowing them to plug in to receptor molecules throughout the body, turning on and off much of the cellular behavior that makes us tick.

Pretty slick! Bioidentical hormones are those whose biochemical structure exactly duplicates those found “naturally” in the human body—that is, the ones whose structure has evolved for millenia. Why mess with a good thing?

True Natural Hormones

The molecules naturally produced in the human female body for which we most often seek replacement include the following: a) the three basic types of estrogen: estrone (E1), estradiol (E2), and estriol (E3); b) progesterone; c) testosterone and d) DHEA, an adrenal precursor to testosterone. These truly “natural” hormones are available by prescription (or, in the case of progesterone and DHEA, over-the-counter in low doses), and can also be readily titrated to a woman’s individual needs. Though many health care practitioners are still not trained in prescribing them, the opportunity is there for them to learn, and health care providers are becoming increasingly aware of their patients’ preferences.

Bear in mind that most of the mainstream studies have been performed on conventional HRT. In addition, pharmaceutical companies cannot take out a patent on what the majority of human women make effortlessly on a daily basis and, therefore, cannot generate large sums of money by packaging and selling them. This may explain why women are commonly offered prescriptions for nonbioidentical forms of HRT, while their efforts to obtain a prescription for bioidentical HRT can be met with varying degrees of skepticism. On the other hand, unique delivery systems for HRT are patentable, and for this reason options for HRT delivered via transdermal skin patches abound, some of which are bioidentical. Examples include many of the estrogen patches, including Vivelle, Estraderm, and Climara.

Most women know that Premarin, Prempro, and Provera are not bioidentical. My colleague Dr. Joel Hargrove says, “Premarin is a natural hormone—if your native food is hay!” (It’s made from conjugated mare urine.) Provera was developed as a substitute for bioidentical progesterone (the kind found in the human female body) because you cannot patent a naturally-occurring hormone! Prempro is a combination of Premarin and Provera.

If you are in doubt as to whether a particular product offered to you by prescription is natural, check the label—if it lists anything other than the above ingredients, including “esterified estrogens,” “progestins,” or “progestogens,” the product is essentially not bioidentical. You can also go to your library and look the product up in the most up-to-date Physician’s Desk Reference, or try plugging it into your favorite search engine on the Internet—many proprietary products even have their own site.

Many people have written to me to express their confusion about the use of progesterone creams, particularly regarding the efficacy of yam-based or other plant-based creams.

Unlike soy and flax, for example, which contain plant-based estrogens (phytoestrogens) that are adaptogenic and converted into utilizable forms in the body, wild yam (Dioscorea barbasco) cannot be converted into progesterone in the body.

The conversion can occur in a laboratory setting, however, and therefore, wild yam is sometimes used to synthesize the progesterone found in progesterone creams. The cream may technically be yam-based, but its active ingredient is not the wild yam itself but the USP progesterone that has been added. For this reason, while the body may absorb wild yam extract through the skin, which may then confer mild effects on menopausal symptoms, results of research on oral and topical applications of wild yam extract have not detected a significant change in progesterone levels in the blood.

If you want the beneficial effects of bioidentical progesterone, make sure the ingredients on the label include United States Pharmacopoeia (U.S.P.) progesterone. U.S.P. progesterone is available in over-the-counter 2% creams as well as by prescription. Choices for prescription-based bioidentical progesterone include Crinone Vaginal Gel in 4% or 8% concentration, or in an oral micronized form such as Prometrium capsules.

Spiritual and Holistic Options

I receive letters almost daily from women who have taken the initiative to offer their health care providers information on the natural approach to HRT, some with great success and others meeting with failure. In any case, it’s your body, and therefore it’s worth a try.

Here are the salient points to know and to share with your practitioner:

  • Our native human hormones can be synthesized in laboratories to exactly duplicate those found in our bodies.
  • Bioidentical HRT has been prescribed by doctors for many years and is readily available through formulary pharmacies.
  • Bioidentical HRT is easily titrated to suit women’s individual needs, is readily absorbed and utilized, and is safe and effective.
  • Bioidentical hormones are the ones we want to use as replacement therapy, if and when we decide they are necessary.

Learn More — Additional Resources

  • Many physicians and formulary pharmacists work in partnership with their patients to provide individualized hormone-replacement solutions. Ask your physician about this kind of customized care; he or she can call a local formulary pharmacy to consult with a knowledgeable pharmacist. To locate a pharmacy that provides individualized prescriptions, contact:
    International Academy of Compounding Pharmacists (IACP)IACP (formerly known as Professionals and Patients for Customized Care, or P2C2) is a nonprofit organization made up of more than 1,300 compounding pharmacists nationwide. The IACP website has a locator feature that can help you find a compounding pharmacy in your area.
    American Hormones, Inc. This compounding pharmacy was founded by Erika T. Schwartz, M.D., renowned expert in the field of natural hormones. American Hormones offers high-quality pharmaceutical-grade hormones shipped nationwide and internationally. The website has extensive information on bioidentical hormones.
  • For additional information on individualized hormone therapy, contact the Natural Woman Institute. The Natural Woman Institute was founded by Christine Conrad, author of A Woman’s Guide to Natural Hormones (New York: Perigee, 2000). NWI maintains a database of physicians and health practitioners nationwide who prescribe natural, bioidentical hormones.
  • The Wisdom of Menopause, by Christiane Northrup, M.D., Chapter 5, “Hormone Replacement: An Individual Choice”
  • Women’s Bodies, Women’s Wisdom, by Christiane Northrup, M.D., Chapter 14, “Menopause”
  • The 30-Day Natural Hormone Plan, by Erika Schwartz
  • New Menopausal Years, The Wise Woman Way: Alternative Approaches for Women 30–90, by Susun S. Weed
  • TCM: A Woman’s Guide to a Trouble-Free Menopause, by Nan Lu, OMD, LAc, with Ellen Schaplowsky

Christiane Northrup, M.D.

Christiane Northrup, M.D.

Christiane Northrup, M.D., is a visionary pioneer and a leading authority in the field of women’s health and wellness. Recognizing the unity of body, mind, and spirit, she empowers women to trust their inner wisdom, their connection with Source, and their ability to truly flourish.


Add comment
  1. Wendy Norfolk
    1 month ago

    Dr. Northrup, I am interested in the vaginal creams for menopause symptoms. Most of the initial symptoms that I experience in the first couple of years of menopause have significantly diminished, but I am very concerned because (for the first time in my life) I have started to have significant pain during sex. I am happily married, and I have always enjoyed sex. I don’t intend to stop now! However, it is hard to have an orgasm when you are experiencing pain, especially with deep thrusts. I believe that the bioidentical vaginal creams are what I would like to try (I haven’t had a hysterectomy and am age-appropriate for menopause at 53), but I am concerned that most, if not all, of the creams’ bioidentical estrogens are derived from soy. Since most of the soy grown in the US (well over 90%) is genetically engineered, I am not very enthusiastic about slathering glyphosate or bt toxins into my vaginal area!! Are there any products available that are made either from non-soy plant derivatives (that are still bioidentical and therefore usable by the human body) or are soy-derived, but are 100% certified organic and/or non-GMO certified soy sources? I have searched, but haven’t found much on this to date.

    Please help!!

    Thanks so much,

    Wendy N.

  2. Karyn Palmer
    1 month ago

    Hi Christiane,
    I have come across your work only recently and I have a great respect for what you have done and continue to do. Your fabulous female body course was indeed fabulous .
    So…I am wondering if your Pueraria mirifica would serve me atm or whether i need progesterone as prescribed by the doc.
    I was diagnosed with a dvt in my calf 5 weeks ago along with 2 large PEs and am therefore on blood thinners. This has lead to my already heavy periods (due to fibroids) to become excessive. Probs being that the usual antidote for reducing bleeding ie clotting medication, I cant have. Up till now i have been a very healthy and fit 47yr old with no health issues at all so Im struggling to keep on top of these new developments and trying to keep as drug free as possible!
    I would greatly appreciate some advice!
    Thanks and love to you!

  3. Teresa
    4 months ago

    I had a total hysterectomy there for I am in surgical menopause. I’m taking a black Kosh blend
    And OTC mendapause cream. Both seemed to work well. Then my doctor prescribed Premarin vaginal
    Cream, since the start of the Premarin cream and stopping the OTC cream I was using I have NOT had one good night sleep…any suggestions for sleep and what the heck can help me? Thank you

  4. Kim
    5 months ago

    I can’t seem to locate this website or database of physicians. Can you let me know where to find this as am looking for excellent physician in my area of Boston/southern MA who does bhrt. Thanks
    “NWI maintains a database of physicians and health practitioners nationwide who prescribe natural, bioidentical hormones. “

  5. Sandy
    6 months ago

    I started taking 450mg of PM in June 2016 and twice now I have had extra long (2wk) periods that are heavy. No cramping really but heavy bleeding. I’m currently in the second one. I started retaking the pills hoping for the period to stop but so far it hasn’t. When I restarted the pills I took 2 the first day and 2 the second day and one today. I need help. Am I taking too much or what. I am post menopausal I’m 65 almost 66. I like the effect of the PM and really don’t want to stop taking it. What would the schedule be or the amount be for someone like me. If my period does start (which I have had one every month since I started PM) do I stop taking the pills or continue. Should I reduce the amount I take? I have looked for answers for months and haven’t gotten anywhere. Thank you

  6. Ericka
    8 months ago


    Is topical progesterone safe and effective to stop hair loss and regrow hair? I am about to order a minodoxil/tretinoin/azaelic acid product to try to regrow my hair and it is progesterone in it. I asked if the progesterone is bio-identical or synthetic but the customer service rep did not know and said she would have to contact the compounding pharmacy to find out. If it is synthetic, is it ok to use? Or will it mess up my natural progesterone production? What else can I do to stop the hair loss and get my hair back? Every day I have less hair.

    Thank you.

  7. Sheila crone
    8 months ago

    My GYN recommends Bio-Te Identical Hormone implantable pellets every four to six months. I noticed more muscular strength within two weeks. The drawback is my sexual feelings exploded and I have no partner. I asked to have less testosterone but was told it was the hormone making me feel better overall. My question is : Is Bio-T identical hormones safe? My family practiioner says it will kill me by stroke or heart attack. But she also thinks the only test I need for regulating my thyroid is TSH. No, my hypothyroidism is not managed well at all. Can you help me with finding out how safe the Bio-Te is?

  8. Cathy
    8 months ago

    I am 67 and never took hormone replacement of any kind, nor did I ever take birth control pills during my fertile years. Would bio-identical hormones help me with aging symptoms in general such as forgetfulness? It would also be nice to feel a bit more like the woman I was hormonally before menopause.

    1. Jill
      4 months ago

      If you find an answer, please let me know! I am soon to be 63 & recently started bioidentical hormones for healthy aging. I never took birth control pills & had a natural menopause & have never take. Hormones! I am having trouble finding info regarding post-menopausal women just starting BHRT & the benefits. Most info seems to target women in perimemopause or just going through menopause. I started BHRT to slow down aging, improve skin & hair – is this a falsehood or true. Responses would be appreciated & thanks!

  9. Heather
    8 months ago

    Hello! I was wondering what works for perimenopause and having extra heavy periods? The doctor prescribed nuvaring? Seeing now it is synthetic and worried about the side effects?
    Please let me know if a patch or cream can work like the ring to calm and lighten the periods?

  10. Heather Martin
    8 months ago

    Is there a particular brand of bioidentical progesterone cream you recommend or like better than another?

  11. Michelle
    12 months ago

    I am 52 had radical hysterectomy last year and naturopath put me on compounded bio identical hormones 50mg oral progesterone, .5mg testosterone and 1mg estriol suppository for atrophy. I’m doing better than I was but I’m still symptomatic with insomnia, depression and brain fog. Western doc suggested .25 mg estradiol patch. I have had a kidney pancreas transplant 12 years ago and high risk for cancer due to meds causing cancer. Is estradiol patch safe or can u suggest something else that can help. Thank you.

    1. Christiane
      9 months ago

      The biggest contributor to cancer is excess sugar intake and emotional stress. Alcohol also contributes. Of course mammalian hormones can contribute as well. You probably know all this. You might try Pueraria mirifica liquid or capsules and see if they help. Then wean off the hormones. But all women are different. And at the end of the day, your inner wisdom is the best way to get your questions answered. Still, check out

  12. Terri W.
    12 months ago

    I am 51 and in perimenopause. Should I be using bio identical progesterone cream daily if I’m still menstruating? I also take estrogen and testosterone. My latest urine test shows I’m a little estrogen dominate and my Dr. Is ok with that? Something doesn’t seem right to me.

    1. Kim
      9 months ago

      I would like to know this also.

    2. Christiane
      9 months ago

      The biggest contributor to estrogen dominance is excess insulin from a diet that is too high in sugar. ( A huge problem around the world). So– I recommend that you check out the book Always Hungry by David Ludwig, MD or go to Progesterone is fine. If you’d like to do something non-hormonal that is often very effective, try Pueraria mirifica. And check out my company

  13. Kathy M
    12 months ago

    I’ve been on bio-identical hormones for more than 10 years but would like to get off of them. Is there any information available about how to do that safely?

    1. Christiane L NOrthrup
      12 months ago

      There are a couple ways to do this: The first is just to slowly wean off your hormones by taking one less pill per week the first week, two fewer the second week, etc. Until you are totally off the hormones.

      The SECOND way to do this is to get some Pueraria mirifica — an herbal supplement very rich in phytoestrogens but without ANY of the adverse effects of prescription hormones. Start on this one capsule in the morning and one at night. ( I started a company to bring this herb to the attention of women cause it’s so effective. Then– after a couple weeks on the Pueraria mirifica, just wean off your hormones in about 2 weeks time. This will give your body a nice transition. And you may well find that all the things you experienced on the hormones that you liked are now possible with another type of approach. Thanks for asking!!

  14. Marie
    1 year ago

    Hello I just did a natural IUI , for unknown infertility, and after 5 days I had a blood test to check my progesterone level which seems to be in the normal range but doctor prefers I take progesterone to help implantation. I asked for a more natural one and they prescribed crinone. I am a very sensitive and allergic person and I am just concerned that this could just harm me instead of helping. What do you think? Thank you

    1. Christiane L NOrthrup
      12 months ago

      Crinone is bioidentical progesterone. And I believe you will do just fine on it!

  15. Carol
    1 year ago

    Now that i am on the other side of menopause, what would be the reason to take any kind of hormones?

    1. Christiane L NOrthrup
      12 months ago

      This all depends on how much hormone your adrenals and ovaries are still making. I personally take the the herb Pueraria mirifica for the phytoestrogen content. It keeps everything quite nicely moisturized. And there are also bone, heart, and reproductive system benefits. I started a company to let women know about it. Check out But trust your inner wisdom. You might be just fine with what you’re currently doing!

  16. Karen T.
    1 year ago

    I have been using Pro-Gest progesterone cream for over 20 years(1/4 tsp. 2X a day and then 1/8 tsp. 2X a day). I originally started it to balance Premarin and continued it after stopping the estrogen pills. However, is it possible to have too much progesterone in your body tissues? After all this time, I have developed low thyroid issues, with a lot of joint and muscle pain, popping joints, etc. I wonder if these two are related. Does the progesterone cream have a build-up effect after many years of use? I am 68 years old, normal blood pressure and weight. Thanks so much for your help.

  17. Dyan
    2 years ago

    I think this slideshare will be a good complement to the article:

  18. Tisa C
    8 years ago

    I had to stop and thank you for all your courage and fortitude for standing up against traditional medicine and religion in a loving manner to make our world a better place. You are a hero for women of all ages and I have been privileged to discover your work on my journey. Blessings & Love!

  19. Coleen B.
    8 years ago

    This is so interesting. I recently heard a minister tell of healings in Africa during a mission trip. He said that these healing could take place because there were no obstacles being generated in the mind of the people seeking help. No other options except faith in the healing power of God.

    In a book I am reading, the author states, “we must ALLOW the Spirit (Divine Love-healing stream) to work. I find that statement very powerful.

  20. Stuart M.
    8 years ago

    I loved the meditation that you did on your Wednesday evening Hay House event! Wow! I am so excited to read the book, arriving from Amazon soon! I am sure the book will be wonderful and yet I feel as if I already know this. It feels so true and perfect! Since Wednesday night I have twice found myself stopping what I was doing to follow an urge to send energy to someone far away who has no knowledge of my sending it. Somehow I know it is important for me to send and that they are receiving it and it is healing them. Our paths have crossed many times. You would be amazed to know how you have showed up in my life over the years. As far back as 26 or 27 years ago when I came to a clinic that you were working at. Then at OZ Books in SW Harbor, Maine nineteen years ago next month. I remember because my now 19 year old daughter was a baby asleep in my arms as I listened to a most exciting and provacative lecture! A wonderful Louise Hay event in Atlanta 10 years ago or so…. now with 4 kids I can not be so sure of what happend when as I was when I only had one and she slept all the time …. I have followed your work, read your books and watched your PBS specials and other TV appearences. I have given your books, told people about you! I could go on and on about how much I love and appreciate you and your work! Thank you for the energy and light you put out into the world! Once again you have given me something at the exact time that I needed it. Love and blessings to you!

  21. Kim L.
    8 years ago

    Thank-you so much for bringing this information to us….I feel the healing all around me, as I did after the meditation with you at the “I Can Do It” conference in San Diego….Same Kim that spoke to you on air today….I feel it everytime I meditate with Bruno Groening, the music, with Divine Love guiding the way…..I never would have thought something could feel so right & Divine!! I bless you, & Hayhouse, & Louise Hay, & all involved in this wonderful event we shared today!! Totally Awesome!!! Thank-you………Light & Love KL

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