Anastrozole Arimidex Profile
Pharmaceutical Name: Anastrozole
Drug Class: Aromatase Inhibitor
Active Life: 48 hours
Anastrozole is an aromatase inhibitor. Aromatase inhibitors prevent the
conversion of androgens into estrogen in fat, muscle, breast, and brain (1).
The medical use of Anastrozole is primarily to inhibit the progression and
growth of breast cancer in women by blocking the aromatase enzyme. It has also
been used by some doctors to try and treat low testosterone production in men,
as well as being used in conjunction with testosterone replacement therapy.
For bodybuilders and strength athletes, Anastrozole is used to minimize the
aromatization of anabolic steroids, and to a lesser extent for it's ability to
raise testosterone levels in users. By reducing the amount of estrogen in a
steroid user's body he will be able to avoid estrogen related side effects
such as water retention, gynocomastia, etc (2). Obviously this is something
that users should be hoping to limit as much as possible.
Interestingly, in addition to decreasing estrogen it has been demonstrated
that anastrozole can also increase testosterone levels by up to 58%, along
with also raising levels of lutenizing hormone (3). This is quite significant
especially when one considers that anastrozole can be used in conjunction with
other compounds during a user's post cycle therapy to raise natural
testosterone levels once administration of anabolics steroids is completed via
the hypothalamic testicular pituitary axis.
How to properly use and dose Arimidex
In the majority of users, .5mgs per day should be enough to prevent any
estrogen related side effects related to anabolic steroid use. Even when doses
were increased to 1 mg per day there was no change in the amount of estrogen
that was able to be reduced as compared to doses of .5mgs per day (3). This
would seem to indicate that raising your dosage will show no further results
if estrogenic side effects continue to be a problem at a dosage of .5mgs. If
symptoms persist the user may have to try a more potent compound such as
Having said all of this however, most users will be able to reduce any water
retention that they may have, or other estrogen related side effects, with
dose less than .5mgs per day. Anecdotally users have reported that doses in
the range of .25mgs per day or .5mgs every other day are enough to acheive
this result. It is possible to administer anastrozole every other day due to
it's active life of 48 hours.
For users using anastrozole during their post cycle therapy the same dosages
should apply. There is no need to increase or decrease dosages. It can be run
throughout the post cycle period with no ill effects.
Blood levels of the compound should stabilize and reach their peak at about
7-10 days after first administering the drug (5). Therefore it is unlikely
that a user would need to frontload with anastrozole or begin taking it before
they start administering the anabolics that they plan on taking.
Side Effects/Risks of using arimidex
Anastrozole is seemingly very mild on blood lipids (cholesterol) and has not
been shown to affect them adversely (6,7). However it should be noted that in
theory if one was to consistently suppress your natural estrogen levels for a
long period of time, this would negatively impact your health (including your
cholesterol). Despite this there is no scientific evidence that anastrozole
can be dangerous for healthy individuals to use, even for extended periods of
It would seem then that anastrozole has little in the way of negative side
effects associated with it's use. It is by far one of the safest compounds
that an athlete can use.
1. Preclinical pharmacology of "Arimidex" (anastrozole:
ZD1033)--a potent, selective aromatase inhibitor. J Steroid Biochem Mol Biol
2. The ATAC Trialists Group. The ATAC (Arimidex, Tamoxifen, Alone or in
Combination) adjuvant breast cancer trial in post-menopausal women with early
breast cancer. Lancet 2002; 359: 2131-39
3. Mauras N, O'Brien KO, Klein KO, Hayes V. "Estrogen suppression in males:
metabolic effects." J Clin Endocrinol Metab. 2000 Jul;85(7):2370-7.
4. Leder BZ, et al. "Effects of aromatase inhibition in elderly men with low
or borderline-low serum Testosterone levels." J Clin Endocrinol Metab. 2004
5. Taxel P, et al. "The effect of aromatase inhibition on sex steroids,
gonadotropins, and markers of bone turnover in older men. J Clin Endocrinol
Metab 2000 86:2869???2874
6. Dougherty RH, et al. "Effect of aromatase inhibition on lipids and
inflammatory markers of cardiovascular disease in elderly men with low
Testosterone levels." Clin Endocrinol (Oxf). 2005 Feb;62(2):228-35.
7. Hayes FJ, et al. "Aromatase inhibition in the human male reveals a
hypothalamic site of estrogen feedback." J Clin Endocrinol Metab. 2000
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