“Bio-identical” Hormone Replacement Therapy

Keris KrennHrubec and Diana Zuckerman, PhD

First published January 2008. Revised August 2010.

To avoid the risks of hormone replacement therapy, more and more women are turning to alternatives. How safe are they?

Major research studies have reported that hormone replacement drugs can increase a woman’s risk for heart disease, breast cancer, and stroke. (For more information, please visit: Hormone Therapy and Menopause ). The most widely-used hormone drugs (Permarin and Prempro) are made from animal hormones.1 Most other hormone drugs are made from plants or are completely synthetic. “Bio-identical” hormone therapy is a new term used to describe drugs that contain hormones that are more similar (although not necessarily identical) to the hormones that naturally occur in the human body. However, since the term is not recognized by the Food and Drug Administration (FDA), the definition is used different ways by different people and organizations.2 Most of these new drugs are mixed in pharmacy operations, and never had to prove to the FDA that they are safe or effective. Some people are claiming that because these drugs are more “natural”, that they are better for you. They are also making false claims that they can prevent or treat diseases such as Alzheimer’s, strokes, and some cancers.3

Hormone therapy used for menopause includes two hormones: estrogen and progesterone.1 However, there are many different kinds of estrogen and progesterone that can be used, and “bio-identicals” usually use an estrogen called estriol.3 There is no substantiated evidence that these so-called “natural” therapies are safe or effective, and certainly no proof that they are safer or more effective than current FDA-approved hormone therapy. In fact, since they are very similar to the drugs already on the market, it is likely that they will produce the same side effects. Manufacturers and some health professionals are misleading women, doctors, and health care providers by claiming that these drugs are a better and safer treatment than the FDA-approved treatments.

Why Aren’t “Bio-Identicals” FDA-Approved?

Bio-identical drugs are made by pharmacy operations in a process called “pharmacy compounding,” instead of being manufactured the way most drugs are. In this process, the pharmacist alters or changes a drug that had previously been approved by the FDA. However, when the drug is modified in the compounding process, it is no longer FDA-approved.4

The goal of pharmacy compounding used to be to allow a medical prescription to be customized for a particular patient, typically to dilute a particular drug, or to make a medicine made without certain ingredients that cause allergic reactions. In many cases, this kind of compounding is beneficial to the patient, but it is not without risks.4

However, pharmacy compounding can allow untested drugs to be widely sold to millions of people. When FDA-approved drugs are changed during the compounding process, serious problems can arise because the production standards of compounding are not required to be regulated or monitored.4 After compounding, consumers have no assurance that the product was appropriately made and is the correct dosage. Since the compounded drugs are new concoctions that are not FDA-approved, and have not been tested in controlled clinical trials, their safety and effectiveness is not known.4

“Bio-identicals” are made through this process with the claim that they are being tailored to a specific woman’s need. In reality, however, there is no evidence that the hormones are being tailored for individual women. Most important, these drugs tend to contain estriol, a drug which is not FDA-approved for any use.2

Why are “Bio-Identicals” a Problem?

It is possible that “bio-identicals” produce the same benefits and risks as regular hormone therapy. Since there haven’t been any clinical trials, however, nobody knows either the short-term or long-term side effects. And many pharmacy operations are making misleading or inaccurate statements, persuading women that they are receiving an improved treatment, when what they are getting is a drug that is unregulated and possibly dangerous. Not only are “bio-identicals” subject to the normal concerns of compounded medication, but women are falsely being told that they are safer and more effective than other hormones, and that they will prevent other serious diseases.

The FDA Takes Action to Protect Women’s Health

In response to those concerns, in January 2008 the FDA sent warning letters to seven pharmacy operations regarding the claims that they routinely make about the safety, efficacy, and superiority of “bio-identicals” as a treatment for menopausal symptoms.3 The claims that these pharmacy operations were making are completely unsubstantiated. In their warnings, the FDA told the compounding pharmacies that such false and misleading statements are a violation of federal law.3 However, the pharmacies are allowed to sell the bio-identical drugs as long as they don’t make false claims about them.5

How Do I Know if My Hormone Therapy has been Compounded?

This kind of compounding is only legal if it is in response to a doctor’s prescription.3 It is unlawful for a pharmacy to simply give you modified drugs without consent. However, the FDA recommends several tips for protecting yourself on their Web site at http://www.fda.gov/consumer/updates/compounding053107.html#do. This includes talking with your doctor about FDA-approved therapies, as well as talking to your pharmacist about any compounded therapy you receive.

Not all “bio-identicals” are compounded. However, if they have estriol in them, they have not been approved by the FDA.

Your doctor may have recommended “bio-identicals” and/or compounded hormone therapy to you. That is legal, as long as false claims are not being made that the products are safe or effective. However, patients need to know that these products are not as carefully evaluated as other drugs that are sold in the U.S. Even if there are published studies indicating that they are safe or effective, the studies were most likely conducted by researchers who are paid by someone who makes money from the sale of the product, and not carefully scrutinized to make sure the studies were conducted properly and the results were accurately described in the publication. It is impossible to be completely informed under these circumstances, so consider the lack of information when you make a decision about whether to try a “bio-identical” hormone product.


1 National Institutes of Health. (July 2006). Hormones and Menopause: Tips from the National Institute on Aging. Retrieved from: http://www.niapublications.org/tipsheets/hormones.asp

2 FDA/Center for Drug Evaluation and Research. (2008, January 9). Compounded Menopausal Hormone Therapy: Questions and Answers. Retrieved from: http://www.fda.gov/cder/pharmcomp/BHRT_qa.htm

3 FDA News. (2008, January 9). FDA Takes Action Against Compounded Menopause Hormone Therapy Drugs. Retrieved from: http://www.fda.gov/bbs/topics/NEWS/2008/NEW01772.html

4 FDA Consumer Health Information. (2007, May 31). The Special Risks of Pharmacy Compounding. Retrieved from: http://www.fda.gov/consumer/updates/compounding053107.html

5 FDA Consumer Health Information. (2008, January 9). Bio-Identicals: Sorting Myths from Facts. Retrieved from: http://www.fda.gov/consumer/updates/bioidenticals010908.html