Anti-Oestrogens – Everything you need to know about Arimidex (Anastrozole)


Anti-Oestrogens – Everything you need to know about Arimidex (Anastrozole)

Welcome to the first in the Anti-oestrogenic drugs series. We will start off this series by looking at one of the more popular anti-oestrogens, Arimidex (Anastrozole).

This is a relatively new drug, first developed in 1995, it was developed to contend with Tamoxifen for adjunctive treatment of hormone receptor positive breast cancer. It was found to potently inhibit the aromatase enzyme. An enzyme responsible for conversion of testosterone into oestrogen. It is well known to potently suppress oestrogen and cause greater regression of hormone receptor positive breast cancer, much more so than tamoxifen. It suppresses endogenous oestrogen production by 80% when used at a dose of 1mg daily. Not long after these studies were published the bodybuilding community started to utilise it to effectively reduce aromatisation of exogenous steroids.

What are the side effects?
The most commonly experienced side effects are hot flashes, fatigue, mood changes, joint pains, nausea, vomiting, headaches and an increase in blood pressure. A more serious side effects is the change in bone mineral density that occurs which puts the person at risk of osteoporosis. They should not be used during pregnancy. Furthermore, the reduction in oestrogen means that the cardioprotective and neuroprotective qualities of oestrogen are lost. This put the individual at greater risk of cardiovascular disease due to the changes in cholesterol. In bodybuilders, the addition of Arimidex to testosterone causes an even larger decrease in HDL (good cholesterol) and thus Tamoxifen should be considered in these cases.


How is it used?
The recommendations for athletes using this drug off-script varies. Anastrozole is very popular amongst athletes due to its effectiveness and 0.5 mg to 1 mg a day may reduce serum oestradiol by about 50% in men. Every day or every other day dosing may be utilised. The only way to ensure your oestrogen is in a good range is through blood work. In addition, some agents have higher aromatisation rates than other agents which will alter dosage and timing. Whilst high levels of oestrogen may produce unwanted side effects, so will low levels. Therefore, the goal should never be to crash oestrogen unless one is prepping for a competition and wants to lose additional water weight. A ‘harder’ and more defined appearance will be achieved with high levels of this drug which is why it is commonly used for losing weight.

This is everything you need to know about Arimidex (Anastrozole).


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