Arimidex (anastrozole) is an aromatase inhibitor that now has widespread adoption
by both women and men. Arimidex was originally developed to help in the
battle against breast cancer but was heavily used by male steroid users and,
shortly after, fertility and sports medicine physicians. These off label
usages have been steadily
growing, especially among the steroid community, whose
supraphysiological testosterone levels often require the brakes be put on
their heavy aromatization and all its ensuing side effects such as
gynocomastia, mood changes, loss of libido and erectile dysfunction.
There are also a couple of additional usage relating to testosterone levels that have caused
its usage among men to acclerate even further:
1) Pseudo-HRT. Arimidex can boost testosterone and the
testosterone-to-estradiol ratio very significantly. This can make it a
viable short term solution for many men with low testosterone since it preserves
fertility and can solve some estrogen-related problems. An even bigger
driver is the fact that at least half the male population is overweight or obese. In my link on
Testosterone and Arimidex,
I cover how one study in senior men showed an average testosterone increase of
62% and a boost in the testosterone-to-estrogen ratio of 112%! Not bad for
just popping a pill, eh?
Need to boost your Nitric Oxide naturally through food, drink and supplements? Check out Lee Myer's book here:
The Peak Erectile Strength Diet
Or do you need the most comprehensive testosterone book in Amazon? Here it is:
Natural Versus Testosterone Therapy
2) Estradiol Dampening on HRT. Men
with low (hypogonadal) testosterone levels can end up with overly low estrogen
levels such that they actually begin to experience bone loss and, eventually,
osteopenia. (Quite a few men will even go to full-fledged osteoporosis.)
However, the opposite situation is actually occurring with some men going
on the new testosterone therapies where testosterone is pushed well above 800
ng/dl, i.e. weekly injections or pellets. In these cases, many men who are
(generally but not always) carrying extra weight will find that their estradiol shoots way up at the
same time. So you may have a man with testosterone of a 1000 and estradiol
of 100 that nullifies the effect of the raised testosterone. E2 levels this high will usually put the brakes on erectile
strength, libido and are a risk factor for many nasty conditions.
The solution? Many practitioners are now relying on Arimidex to handle the
elevated estradiol issue, so it is becoming increasingly common for men to be on high dose
testosterone and low dose Armidex to lower one's bloated estradiol levels. And, from
what I have seen, the physician does not think of Armidex as a short term
solution while he insists on weight loss with his or her male patient.
Instead, Armidex is considered part of a package HRT solution.
As always, I am very concerned about packaging Arimidex as a long term, "natural"
solution. Arimidex is a pharmaceutical and it has many potential long term
problems associated with it. Here are a few of the sobering health issues that
you should discuss with your doctor before you consider this as a
1. Negative Alterations of Inflammatory Cytokines. One study showed
that "anastrozole induced the increased levels of proinflammatory cytokines,
IFN-gamma, IL-12, and the decreased levels of IL-4, IL-10 secretion. We further
found that anastrozole suppressed the differentiation of naive T cells to Treg
cells, and it blocked the balance of IgG2a/IgG1 in peripheral blood."  This
is potentially ugly as I would argue that
Inflammation is Enemy Number One. The last thing most guys need to
accelerate systemic inflammation by even a small amount.
2. Joint and Arthritis Risk. One very common risk of Arimidex
treatment is joint pain and/or arthritis. The study above concluded that
"anastrozole potently promote the progression of arthritis." One study on women showed that Arimidex users had a higher than
expected number of complaints about joint issues.  (Just because this was
on women does not mean it does not apply to men. Many men complain of
joint issues while on Arimidex.) Now I should mention
that most of the study work has been done on women who are on Arimidex for breast
cancer treatment. Their estrogen is brought down very low. Men who
have moderate estradiol adjustment into youthful E2 levels are obviously a
different animal altogether. In other words, men on low dose Arimidex will
probably not have this concern, unless their doctor does not monitor and
unwittingly pushes his patient's estradiol too low. I have see this happen
on The Peak Testosterone Forum.
3. Liver Toxicity. Arimidex is mildly liver toxic in some
individuals. For example, one study of men found that liver enzymes were
raised in about 7% of men.  Now, admittedly, this is generally not a major
issue, but liver function is extremely critical. See my links on
and Insulin Resistance and
The Liver and Inflammation
for examples. Again, is this going to be good over decades?? NOTE:
This is probably not an issue for men on low dose Armidex.
NOTE: In my link on Arimidex and HRT, I discuss a number of other important
reasons that men on HRT may want to limit their Arimidex usage as well. You may also want to check out my link
Natural Estrogen Blockers if you want, under your doc's supervision of course, to go to a more
supplement or lifestyle-based approach.
4. Possible Clotting Issues. Arimidex can interfere with the clotting cascade. See my
page on The Risks of Testosterone for more information. It is possible that men
with certain clotting or cardiovascular risk factors could get themselves in trouble.
5. Vitamin D Depletion. Some researchers speculate that Arimidex depletes
Vitamin D as they have found that patients with muscle and joint pains on
Arimidex have lower than expected levels of Vitamin D, although this is not
proven yet. Practitioners have also noted that taking extra Vitamin D
helps with a variety of side effects and one study in women even verified this.
Forum poster on Arimidex was put on high dose Vitamin D and my
guess is that this is the reason.  Extra Vitamin D has also been known to
help with rheumatoid arthritis.  NOTE:
This is not an issue for men on low dose Armidex who also have their 25-hydroxy
6. Estradiol Crash. Some men on the forum have reported that even small amounts of Arimidex have crashed their estradiol levels.
seem sensitive to even very small dosages and often have to go to compounded Arimidex. However, we also had one
troubling story on the
Peak Testosterone Forum, where a man took Arimidex as part of an HRT (TRT) protocol and found his estradiol had tanked to below 5 pg/ml in two separate blood draws. Furthermore, both blood draws showed his total testosterone to be above 850 ng/dl, so it was definitely not due to a lack in testosterone. Something about the Arimidex seemed to completely shut him down. 
CONCLUSION: As you can see, generally the side effects of Arimidex are usually negligible assuming one is taking relatively small dosages. However, there are several nagging concerns that, hopefully, will one day be addressed. My opinion: if you are going on testosterone therapy, get those abs back!
Yes, you can try Armidex short term. But do what it takes to lower your body fat percentage to where you can see a
nice line down those abs: this usually will dramatically lower your
aromatiziation and, therefore, estradiol levels even on high dosages of
testosterone therapy. I have seen estradiol greatly reduced in men who
have gotten their weight way down.
CAUTION: Natural aromatase inhibitors are few and far between at this
point. I do not recommend chrysin, because it can affect the thyroid, nor
too much zinc, as it can lead to copper depletion potentially
Experimental Gerontology, Jun-Jul 2009, 44(6-7):398-405, "Immoderate inhibition
of estrogen by anastrozole enhances the severity of experimental polyarthritis"
2) Breast Cancer, 2006;13(3):284-8, "Joint symptoms: a practical problem of
3) The Journal of Urology, Feb 2002, 167(2 Part 1):624–629,
"AROMATASE INHIBITORS FOR MALE INFERTILITY"
5) Arthritis Rheum, 2004 Jan, 50(1):72-7, "Vitamin D intake is inversely
associated with rheumatoid arthritis: Results from the Iowa Women's Health