Flurry of FDA action against aromatase inhibitor supplements

A bodybuilder with Grade I gynecomastia (left) and after symptom resolution. Source: Dr. Mordcai Blau, Wikimedia Commons

If you've ever met me, you'll know that I'm not a bodybuilder. That's why I was taken aback earlier this year when I learned that men are taking aromatase inhibitors - and not for breast cancer. This education came to me when I was asked by a network news program to comment on a litany of drugs and supplements found in the possession of self-proclaimed guru James Arthur Ray following the Sedona sweat lodge deaths at one of his "Spiritual Warrior" retreats. Among the bodybuilding supplements and testosterone replacement drugs authorities found in his possession was anastrozole (Arimidex), for which he had a valid prescription.

Aromatase catalyzes the appropriately termed aromatization of testosterone to 17β-estradiol (Wikimedia Commons)

Strategies to increase testosterone in men - indirectly or with direct testosterone supplementation - run the risk of causing feminizing side effects. The goal in these settings is to prevent gynecomastia and testicular atrophy by preventing testosterone from being aromatized to 17β-estradiol or androstenedione from being converted to estrone. So, no, my pharmacist friends: the rash of aromatase inhibitor prescriptions you're filling for men does not indicate an epidemic of male breast cancer - normally only 0.8% of breast cancer cases. Earlier this month, I noticed that the US FDA announced a series of "voluntary product recalls" from supplement manufacturers whose products contained an aromatase inhibitor, 1,4,6-androstatrien-3,17-dione, or ATD. The compound has also been cited under the names 6-etioallochol-1,4-diene-3,17-dione, 1,4,6 etioallocholan-dione, or 3,17-keto-etiochol-triene. Due to the unusual regulation of dietary supplements in the US, when such products contain an undeclared drug or other agent not classified as a dietary ingredient, FDA usually encourages companies to recall their product and issue a warning to consumers. Five such warnings came out between September 13 and 16, leading FDA to issue a summary warning on September 20. The full text and links to the five warnings can be found here but this is the general issue in FDA's language:
ISSUE: Products marketed as dietary supplements contain aromatase inhibitors, commonly known as “ATD.” Adverse events associated with the use of aromatase inhibitors could include the following: decreased rate of bone maturation and growth, decreased sperm production, infertility, aggressive behavior, adrenal insufficiency, kidney failure, and liver dysfunction. Consumers with liver, kidney, adrenal, or prostate abnormalities are at higher risk for developing adverse events. BACKGROUND: The FDA concludes that products containing aromatase inhibitors have a reasonable probability of resulting in permanent impairment of a body structure or function in at risk consumers. FDA has notified manufacturers that these products do not meet the definition of a dietary ingredient and therefore the product is in violation of provisions of the Food, Drug and Cosmetic Act.
The FDA alerts cover the following products and I've put the links here so readers can access the individual recalls and warnings: Advanced Muscle Science (Arom-X, Arom-X UTT, Arom-XL, 4-AD, and Decavol), ArimaDex, Clomed, Off Cycle II Hardcore, and iForce - Reversitol. Each of the FDA warnings note that none of the five companies have received any reports of adverse reactions - note wording that adverse effects "could include the following..." Therefore, it's not yet known if any of the products contain enough ATD to cause side effects. The widespread use of these products and these recalls obviously have no impact on off-label prescribing of AIs. However, clinical trials are ongoing for the use of AIs in andropause or hypogonadism in elderly men, male infertility/obesity-related oligospermia, and improving insulin sensitivity in obese men.

Author: David Kroll

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  1. Nice read. I also read a little piece about gynecomastia on an Australian bodybuilding site that is a manufacturer of protein powder among other things, but they have a pretty awesome article base which might benefit some people here since all the articles are written by doctors and health professionals. Cheers

  2. Given the relative ubiquity of environmental estrogen agonists, (such as bisphenol-a) as well as the impact estrogens have on a male’s testosterone levels, I’m somewhat surprised the FDA is pursuing these manufacturers as aggressively as they are. While some “performance enhancing drugs” do indeed have potentially harmful or even fatal side effects, aromatase inhibitors rarely exhibit the magnitude and frequency of side effects as do testosterone analogs. Shaking down “mom and pop” manufacturers who are producing a fairly innocuous compounds serves neither the interests of justice nor public health.

    For those who are genuinely concerned about the availability of aromatase inhibitors, the common white cap table mushroom, available at your local grocer, has been shown to inhibit aromatase on par with several schedule III drugs. Perhaps the FDA can turn it’s inquisition towards mushroom cultivators next.

    • J Cimino’s comment on FDA attacks on supplements that are unlikely to really be harmful and which have had no reports of adverse effects as compared to others, is right on.

      And his/her antidote to Federal Idiocy, Excess and power-grabs is even better! Wake up people… they want to control everything.
      THANK YOU J C !

  3. Not surprising that drug supplements are getting looked at closer, people overdose too easily on anything over the counter. If mushrooms really do have higher levels, it shows how complicated getting a fixed study with an easy baseline.

  4. Not to sound like a conspiracy theorist but one can’t help but wonder if population control is hinted at. We’re bombarded with estrogen, male fertility has dropped by half since the 1950’s and here’s an EFFECTIVE supplement that with NO reported side effects in at least 5 years yet the FDA yanks it from the grasp of consumers who otherwise find great benefit from it.
    Simultaneously, it takes them years and sometimes decades to pull drugs which had a mirriad of reported harmful and sometimes deadly side effects attched to them. It all seems a bit suspicious.

    • Its not a conspiracy, just governmental incompetence.

    • No, actually the highest level of ruling elites do want to reduce world population as they have since announcing that around 1970.
      And the plastic bottles (many source of chemicals like GE, estrogen in the drinking water (female urine), estrogenic compounds in antibacterial agents and anything else that makes nominal and correct levels of testosterone available is what they want. This is part of the scheme also of “world peace”, a world full of wussies.
      Further, studies on late pregnancies where less DHEA is available to the fetus shows decreased brain development and performance. That might not be a goal, but explains part of the obvious dumbing down going on.
      Don’t believe the elite want to control you? Read Richard Gardner’s 1974 piece in Foreign Affairs (quarterly of the CFR) where they told you what they were going to do, and have done most of it.

      • Correction to above, should read
        … that makes nominal levels …. unavailable (reduced) as to testosterone.

  5. here’s the funny part: alcohol does the same thing you, it lowers sperm production, causes aggressive behavior, causes liver and kidney damage. it also does something aromatase inhibitors don’t do: kill brain cells. not even marijuana has those side effects. if taken at safe dosages almost any aromatase inhibitor is safe, and some guys like me who are steroid-free powerlifters just happen to have leftover gynecomastia from puberty and there for need AI’s…

  6. For those who are genuinely concerned about the availability of aromatase inhibitors, the common white cap table mushroom, available at your local grocer, has been shown to inhibit aromatase on par with several schedule III drugs. Perhaps the FDA can turn it’s inquisition towards mushroom cultivators next.

  7. There is a better, natural alternative out there which the Myomin. It has been proven really effective in targeting gynecomastia and other symptoms of Estrogen dominance in both male and female. Many BHRT practitioners have been looking into this supplement and most have found it as an effective and safe replacement to common AI’s such as DIM, I3C and Chrysin.


  1. Part Fills for October 6 « Science-Based Pharmacy - [...] All those aromatase inhibitor prescriptions you’re filling for body builders? No, it isn’t breast cancer. [...]