Bioidentical Hormones

The Medical Letter recently evaluated “bioidentical” hormones and concluded

There is no acceptable evidence that “bioidentical” hormones are safe or effective. Patients should be discouraged from taking them.

“Bioidenticals” include progesterone, estrogens (estriol, estradiol, and estrone), and testosterone. They have mainly been promoted as a safer, more natural alternative to menopausal hormone replacement therapy (HRT), but they are also claimed to increase energy, well-being, and quality of life, and to have an anti-aging effect. Suzanne Somers recommends them for all age groups and both sexes. There is no evidence to support any of those claims.

The whole “bioidentical” thing is a pseudoscientific concept: it is a marketing term rather than a scientifically meaningful one. Bioidenticals are promoted by celebrities like Suzanne Somers, a few maverick medical doctors like Kent Holtorf, proponents of “natural” medicine, patients who were frightened by the Women’s Health Initiative study of hormone replacement therapy, and critics of Big Pharma. The mainstream scientific community is in consensus: a number of medical organizations, from the American Cancer Society to the Mayo Clinic, have issued statements similar to that of The Medical Letter.

The terminology is confusing. Bioidenticals are plant extracts modified to have the same molecular structure as endogenous hormones. But there are FDA-approved Big Pharma hormones that are just as “bioidentical”: they are also plant extracts modified to have the same molecular structure as hormones produced by the ovary. Only one bioidentical hormone, estriol, has no corresponding FDA-approved version. It is only present in large amounts during pregnancy: its safety and efficacy as a supplement have not been tested. Proponents of “bioidenticals” make much of the difference between “artificial” Big Pharma progestins and “natural” progesterone, but that same progesterone molecule is also sold as a prescription drug. (Progestins were originally developed because progesterone is poorly absorbed, but now Big Pharma has developed a micronized version of progesterone that is absorbed adequately.)

One of the biggest concerns is that “bioidenticals” are prepared in compounding pharmacies that are not regulated. The FDA has long been concerned about these pharmacies. In a 2006 survey, the potency ranged from 67.5% to 268.4% of the amount specified on the label, and there were variations within the same samples. Contaminants have also been found, including bacteria. Package inserts describing risks are required for FDA approved products but not for compounding pharmacy products.

From 1990 to 2005, FDA learned of at least 240 serious illnesses and deaths associated with improperly compounded products. Because pharmacists are not required to report adverse events to FDA, there may be additional deaths and injuries of which the agency is unaware.

Another big concern is that dosage is usually guided by salivary hormone levels, which are unreliable. Suzanne Somers even advocates that the patient adjust her own dosage from day to day just depending on how she feels.

Advocates claim that bioidenticals are safer than pharmaceuticals, but since they are essentially the same compounds, there is every reason to think they would have the same side effects. At least 3 cases of endometrial cancer have been reported in women taking bioidentical hormone replacement therapy.

Critics complain that Big Pharma is profit-motivated. Interestingly, bioidenticals are more expensive than the Big Pharma versions of the same hormones and they are not covered by insurance.

Proponents speak of individualizing dosage to “balance” the hormones, but I can’t understand how they could ever hope to do that. The body produces several different hormones and the amount of each varies according to the stage of the menstrual cycle. With each constantly going up or down, how could you define balance or hope to mimic the natural state?

“Bioidentical” hormones may satisfy some of the psychological needs of people like Suzanne Somers, but they don’t satisfy the requirements of science-based medicine or even of common sense.

Posted in: Pharmaceuticals

Leave a Comment (33) ↓

33 thoughts on “Bioidentical Hormones

  1. Can you clarify the legal status of “bioidentical” hormones?

    Are they being sold as dietary supplements? Is their inclusion in this category unambiguous?

  2. superdave says:

    I bet if they called them bioidentical steroids no one would want them

  3. Watcher says:

    It’s amazing to me that people are so willing to monkey with the intricacies of the endocrine system. So much depends on these fine-tuned biochemical interactions.

  4. LovleAnjel says:

    They are sold as supplements & are added into lotions. An acquaintance is a part of an MLM company that sells (among other things) bioidentical hormone-powered lotions to help women get pregnant– scary! I don’t know if there is a cosmetics regulation that covers that or if it also falls under DSHEA.

    And yes, it’s touted as 100% safe with no side effects because it’s plant-derived and therefore more “natural” than pharmaceuticals. I have to bite my tongue a lot during her visits.

  5. Recovering Cam User says:

    You’ll find some of them in both categories, Alison – OTC products that can be bought by anyone such as yam creams, and formulations of actual progesterone that are only available by prescription.

  6. WilliamLawrenceUtridge says:

    Some are over the counter (progesterone cream, DHEA) while most of the estrogens are not. Right now I believe the only place in the US you can get estriol is compounding pharmacies. I substantially wrote the BHRT wikipedia page, the references section has a ton, a ton of free, full-text articles in it, with lots of really nitty-gritty review articles. The whole thing is absurd – bioidenticals already exist, and they have known side effects. The only difference between BHRT and “conventional” HRT is compounding, since you can ask your doctor for “bioidentical” hormones produced by major manufacturers with much better quality and safety standards. The approach gets wrapped up in a “natural” rhetoric. Possibly because they’re “identical” to human hormones, possibly because they’re derived from plants – like most hormones are – and possibly because they don’t need to be manufactured. Proponents are never really clear what “natural means. Calling any HRT “natural” is nonsense since declining hormone levels in the body during menopause is one of the more natural things in the world. Plus, a lot of the objections to the “unnaturalness” of Premarin (equine estrogens extracted and purified from pregnant mare urine) is bunk as it gets converted to a “bioidentical” version in the body. One person I argued with insisted BHRT was different because it used transdermal rather than oral delivery systems. A bit mind-boggling since it conflates drug delivery with molecular structure (in addition to being available as FDA-approved drugs already).

    Some proponents also advocate for (expensive) blood and saliva testing as a way of “adjusting the dose” – which is nonsense since they’re not sure what the ideal dose is (normally the dose is determined by symptom relief, though a careful examination of BHRT claims and methods indicates they also adjust based on symptoms and not testing), it’s unclear if blood and saliva levels are meaningful at the cellular level where the effects take place, and the test materials, which usually are mailed to a distant lab, aren’t necessarily stable for the time and temperature changes they face while being mailed. A lot like quacks will use bogus testing to prescribe the “right” vitamin supplements.

    More fun is the Wiley Protocol, a compounded BHRT approach that actively aims for the hormone levels of a 20-year old.

    Seriously – they know what the risks of these compounds are. They already exist as FDA-approved versions. There is absolutely no reason for BHRT to exist.

  7. qetzal says:

    LovleAnjel writes:

    An acquaintance is a part of an MLM company that sells (among other things) bioidentical hormone-powered lotions to help women get pregnant– scary! I don’t know if there is a cosmetics regulation that covers that or if it also falls under DSHEA.

    As far as I know, DSHEA only applies to products taken orally. In addition, I believe claiming that such a product will help make a woman pregnant makes it a drug by definition, no matter what’s in it.

    From reading this page, it appears that FDA’s “light regulatory footprint” for these products is mainly because they’re typically made by compounding pharmacies. I’m not sure how a product sold through an MLM company would fit into that though. I suspect marketing such a product directly to consumers may be illegal. Whether FDA is likely to take any action is another question, of course.

    I have to bite my tongue a lot during her visits.

    I don’t see why. If a friend of mine mentioned that once, I might bite my tongue, but if they brought it up repeatedly, I’d most likely tell them what I really thought. Politely, of course.

    Your friend probably won’t listen to you if you do, and she’ll probably keep using/selling the products (given that she’s part of the MLM). But there’s at least a chance that she’s not really aware of the problems and risks, and that she’ll reconsider, or do more research, or ask her doctor.

    If nothing else, maybe she’ll at least stop bringing it up during her visits. Your tongue won’t be so sore afterward! ;-)

  8. jaa says:

    I think you need to learn more about bio-identicals hormones before posting.Bio-identical hormones are available at standardized dosages approved by the FDA. Some drug names are: Estrace, Evamist, Vagifem, Estraderm, and Climara for estrogen and Prochieve, Prometrium, and Crinone for progesterone. AFAIK, we don’t have any studies comparing “FDA Approved” Bio identical estrogen to Premarin.
    I believe you are doing a disservice to all by equating bio-identical hormones to compounding pharmacies.

  9. LovleAnjel says:


    I get a pitch on a different line of products every time, and since I haven’t ordered anything yet (who buys a a $75 bottle of hand lotion?) it has slowed down a bit. I like the free samples though, so I try not to discourage her too much.

    My favorite line from her 1st sales pitch was “I know this looks like a pyramid, but it isn’t.” Very entertaining.

  10. WilliamLawrenceUtridge says:


    Harriet seemed to make that very point in the article, as did I. And as far as I know you are correct, there are no studies comparing Premarin to other types of estrogens. This is a recognized failing – most industry-funded drug research doesn’t do useful comparisons ’cause it means they’re still able to market new drugs as “new” rather than “better than the old ones” if the data indicates there’s no real difference. Comparisons of dose, type, and route of administration haven’t been done on a large scale, but need to – and these studies shouldn’t be presented as “bioidentical versus other”, it should be “X versus Y hormone for Z condition on A population using B route of administration”. But that’s a huge sample with a lot of comparisons. Each hormone can be expected to have risks and benefits that are different for different people. Since so many of the “bioidentical” hormones already exist as FDA hormones with known risk and benefit profiles, the substantial difference between “bioidentical” and “conventional” is a fuzzy, blurry, (and as Harriet says) primarily marketing-driven distinction.

  11. superdave – “I bet if they called them bioidentical steroids no one would want them”

    My guess – they’d appeal to a different target market, but only if they are sold with the promise that they don’t show up in doping tests.

  12. Joe says:


    May I add: One of the talking points for “Bioidenticals” is they were prepared to match the needs of the particular patient (also explained by Harriet). Hence, the connection to compounding. I looked into this a few years ago and I recall the American College of Gynecologists adopting the position that such adjustments were not necessary.

  13. weing says:

    Timely post Harriet. I just saw a patient taking bioidentical hormones and adrenal support for “adrenal fatigue” diagnosed by salivary gland hormone levels.

  14. WilliamLawrenceUtridge says:

    Weing, you may be interested in this article for its sections on saliva testing, as they give the biological rationales why it’s not helpful:–%20Cirigliano.pdf

    – the section titled “Individualizing therapy and saliva tests” on page 613 (14 of 32).

    Lisa Boothby and Paul Doering also wrote two extensive articles on BHRT, one in 2004 (“Bioidentical hormone therapy: a review”, PMID 15167316) and one in 2008 (“Bioidentical hormone therapy: a panacea that lacks supportive evidence” PMID 18660693).

  15. weing says:

    Thanks, will check them out.

  16. Jann Bellamy says:

    Thank you, thank you, thank you, for this explanation of “bioidentical” hormones. I’ve heard about them — mostly at the gym, which seems to be a great repository of woo. We have an OB/GYN in my city who’s made a specialty of prescribing them and of course some people “swear” they feel better after taking them. Sounds like a very expensive placebo effect. I’ve always wondered about them but never got around to looking it up.

  17. WilliamLawrenceUtridge says:


    Oh, it’s not a placebo – these are hormones! Real physiological effects, significant ones, along with significant risk! We know all about their effects since they have been studied for decades. That’s a big part of the nonsense – it’s not that the hormones don’t work, it’s that they’re oversold as a) doing far more than what we know hormones actually do and b) being far safer than other, “nonbioidentical” hormones.

    But they are more expensive, and I’m quite sure many of the benefits are enhanced (or created) by the placebo effects. Never forget, you could legitimately get these exact hormones from virtually any pharmacy for years now.

  18. Harriet Hall says:

    Most of the benefits Suzanne Somers claims for bioidentical hormones are not documented real physiologic effects but due to placebo response, misinterpretation, or regression to the mean. The way advocates use them produces placebo responses, but these drugs are not just placebos because they also have serious physiologic effects.

  19. Joe Doherty says:

    Advocates claim that bioidenticals are safer than pharmaceuticals, but since they are essentially the same compounds, there is every reason to think they would have the same side effects. At least 3 cases of endometrial cancer have been reported in women taking bioidentical hormone replacement therapy.

    If, as per homeopathy, magic healing properties can be added to water by shaking it, maybe the power of nature imparts magical safety properties to plant hormones that Big Pharma hormones don’t possess.

  20. The Blind Watchmaker says:

    I have been perplexed at how advocates of something that they refer to as ‘identical” can claim that it is both ‘different’ and ‘better’.

  21. WilliamLawrenceUtridge says:

    One thing I’ve never understood – why bioidenticals are seen as a universal panacea, when we have drugs specifically designed to block these very hormones for health reasons. Tamoxifen anyone?

  22. LMAO says:

    Gggrrrrr… this is a subject that just gets me so worked up. I know some legitimate, reputable, heretofore mainstream healthcare professionals who are being eagerly sucked into the world of anti-aging medicine and just makes me ill watching it happen. [I’d love to see SBM do a piece on A4M, its offshoot, the World Council for Clinical Accreditation, and all their ilk… they make chiropractic look positively angelic…]

    Vitally central to the entire industry is this personalized, targeted, chemistry-corrective medicine, which is always based on a whole slew of expensive lab tests, ancillary diagnostics and an evaluation of each patient’s unique lifestyle demands (yes, a female executive has a different “correct” endocrine profile than a female celebrity or a housewife). If the fact that one such clinic is an affiliate of a world-renowned medical center isn’t bad enough, then there’s also the fact that the testing costs through the clinic run roughly three times what the adjacent medical center charges for the same tests! Seriously!

    And yes, I absolutely meant to use the word industry. It’s a multi-million dollar INDUSTRY that now rivals all the other quackeries combined. I know firsthand of clinics and practices being opened up by credible practitioners and providers, who also (conveniently) sell all the necessary “specially formulated” supplements and bio-identical hormones. They actually engage in MLM, providing the formulations through “affiliate” reps! Evidently, the formulas they “provide” or prescribe (not sell) are uber-special and cannot be gotten anywhere else in the world! It boggles the mind that board-certified doctors and multi-decadal hospital administrators with Ph.D.s could actually believe this crap. These are friends and colleagues of mine whom I’ve previously respected. I have to think that they really don’t believe it, and instead have knowingly turned to snake oil for the express purpose of getting rich.

    @superdave, your bio-identical steroids comment immediately brought to mind this great segment that 60 Minutes ran about four or five years ago:

    Gotta love Kroft’s comments about “the ‘temple’ of anti-aging medicine… the Cenegenics Medical Institute in Las Vegas… founded in 1998 by its chief prophet, Dr. Alan Mintz… offering hope to anyone who is feeling tired, getting flabby and losing interest in sex.”

    Temple? Prophet? Buwahahahaha!

  23. viciii says:

    i’m going on 2 years having taken bioidentical hormones. I have never felt better and go for regular check-ups with my physician. My lab work has always come back fine. I definitely wouldn’t give up bioidentical hormones for anything…

  24. Scott says:

    Then you’ve been quite thoroughly taken in by a fraud. I feel very sorry for you, but hopefully they won’t kill you (as they almost did Suzanne).

  25. psavage1 says:

    Just because a star quality persona recommends something certainly is not a reason to accept it. Nor should one just simply dismiss it either. It just “begins” the conversation (as Oprah stated in her telecast).

    However, one cannot just look at the aspect of the pharmacy when discussing BHRT. It certainly cannot be a single one-pill-fits-all solution.

    There are thousands of doctors in the US taking extensive medical training on bioidentical hormones, associated with stellar institutes like the University of South Florida — and their assessment — it works — WHEN it is

    1) Under the care of a highly qualified and trained physician
    2) Working with the best labs (which vary based on the patient)
    3) With a highly qualified compounding pharmacist.

    Look to companies like to find out more on what this is really all about.

    These “scare” tactics are unproductive — and uninformed.

  26. Harriet Hall says:


    You state that “it works.” I’m willing to be convinced: show me the evidence.

    Note that the opinions of doctors who make a living prescribing bioidentical hormones and the unsubstantiated claims of commercial websites do not constitute evidence.

  27. shortandsweet says:

    Until we have scientific evidence saying that they are harmful in any way, I will continue to take them. They have made me feel normal again. No more hot flashes (and they were intense), no more sleepless nights, no more mood swings, my weight has normalized, my skin is not so dry, I have energy again, more mental clarity and I actually have a libido again! I use a Vivelle Dot patch and a compounded progesterone. I have been taking them for over 3 years. I feel like I have gotten my life back. My internist, who specializes in hormone replacement for both women and men, checks my levels every 6 months to make sure they are where they should be. She also, thru my blood work, checks my cholesterol levels, including the LDL particle size, which some docs don’t even know about, my vitamin D level (it’s actually a hormone) and many other things that most docs never test for. She is very thorough. She has written a book on the importance of hormone balancing.

  28. David Gorski says:

    Until we have scientific evidence saying that they are harmful in any way, I will continue to take them.

    Wouldn’t a better approach be to say something like this:

    Until we have scientific evidence saying that they do not carry any risks above and beyond those carried by currently used hormones, it would be prudent not to take them?

    My internist, who specializes in hormone replacement for both women and men, checks my levels every 6 months to make sure they are where they should be.

    Presumably you are postmenopausal (otherwise you probably wouldn’t be taking hormone replacement). Consequently, what level is the level where your hormones should be and what is the scientific evidence to show that this is the level where they should be?

  29. psavage1 says:

    Dear Dr. Harriet,

    Have you considered looking into the Fellowship for BHRT which has it’s Master’s program with the University of South Florida?

    They offer medical CME seminars on the topic of BHRT (all physicians are required to complete the first 5 modules) including also having AMA Board Certification in their specialities.

    You can register for the modules at:

    There are about 2,000 physicians now nationwide that are participating in this training.

  30. john smith says:

    Harriet Hall said:”I’m willing to be convinced: show me the evidence.”

    Dear Harriet,

    When you say you would like to see the evidence, I would assume you are referring to the peer reviewed medical literature evidence, Is this correct? If so, do you accept ALL of the peer reviewed medical literature, or do you accept only portions of it as evidence?

    For example do you accept only placebo controlled randomized trials (RCT’s) and reject all others? OR, do you also accept other types of studies as medical evidence? Because if you accept other types of medical studies, then the Holtorf article in Postgraduate medicine summarizes this evidence quite well.

    Postgrad Med. 2009 Jan;121(1):73-85.

    The bioidentical hormone debate: are bioidentical hormones (estradiol, estriol, and progesterone) safer or more efficacious than commonly used synthetic versions in hormone replacement therapy? Holtorf K.

    The problem with the Cirigliano article is that is was ghost written by Pharmawrite, paid by Wyeth, and only looks at RCT type studies, rejecting all others.

    By the way, bioidentical hormones are gaining in popularity because women are smart customers. They know that biodentical hormones are safer and more effective than Premarin and Provera. You should wise up and join them.

    regards from John Smith,
    a friend of PSavage1

    1. Harriet Hall says:

      When I say I would like to see the evidence, I mean the kind of evidence that would make The Medical Letter change its recommendations. I don’t mean the kind of evidence presented in a second-rate publication by a known promoter of bioidentical hormones who does not have a good scientific reputation. Holtorf lists all those studies, but the Medical Letter experts had access to that information too, and they evaluated the entire body of medical literature and came to a very different conclusion – because they were unbiased.

  31. john smith says:

    Dear Harriet Hall,

    Thanks for your new and unique definition of medical evidence which miraculously depends on what the Medical Letter says. What happens if the Medical Letter goes bankrupt and closes shop?. No more medical evidence? I suggest you try to find a more “science based” definition of medical evidence, because the medical letter isn’t evidence of anything, it’s opinion, and opinions can be wrong, just like your opinion is wrong. By the way, the spouse of the executive editor of the Medical letter takes money from Big Pharma, so it is not exactly as non-biased as you claim. What does Holtorf’s reputation have anything to do with the references he cites? Is this part of science based medicine, to smear the author so you can throw out the “evidence”? This isn’t science, its politics. Go back to your ghost written evidence like the Cirigliano article, that type of pro-industry bias should appeal to you. This blog should be renamed from “science-based medicine” to “politics-based medicine”.

  32. psavage1 says:

    Like John,

    I cannot condone your single source of information as the sole decision of this medicine.

    Have you perhaps reviewed and others as a source of information? Have you considered the multitudes of other sources of training required of physicians in this field?

    This blog is silly if you haven’t reviewed all the sources or at least considered them. Take some time to see what they are teaching at the USF accredited courses.

    Your view is single sided – and a narrow-minded blog. I know educated readers will appreciate that.

Comments are closed.