Anastrozole is a highly powerful anti-estrogen that is officially classified as an Aromatase Inhibitor (AI). Best known by the brand name Arimidex released by Zenaca Pharmaceuticals in 1995, this is the most commonly used AI in testosterone replacement therapy. However, testosterone replacement therapy is not this AI’s primary purpose of use; Anastrozole was developed for breast cancer patients, and it has proven highly effective. For both testosterone replacement therapy and breast cancer patients, the AI works by simply controlling estrogen in the body, which can be a problem for either patient, although for very different reasons.

Functions & Traits:

As an AI, Anastrozole functions by inhibiting the conversion of testosterone to estrogen, specifically by inhibiting the conversion that is brought on by the aromatase enzyme. The aromatase enzyme metabolizes testosterone, converts it to estrogen, and as a result, estrogen levels increase in the body. By inhibiting this process, Anastrozole has the ability to reduce serum estrogen levels in the body by as much as 80%; in fact, such a reduction is very common.

The reduction in estrogen is beneficial for the low testosterone patient because the use of exogenous testosterone can cause estrogen levels to increase, which in turn can promote the most common side effects associated with testosterone use. High levels of estrogen can promote gynecomastia (male breast enlargement), excess water retention and even high blood pressure if water retention becomes severe. Not all men will need Anastrozole or any type of AI during therapy, but the majority will in order to keep serum estrogen levels balanced. If you’re curious as to how this trait is beneficial to the breast cancer patient, it’s actually quite simple. Breast cancer feeds off of estrogen, and by reducing it this can essentially starve the cancer. While perhaps a bit simplistic, it has been a more than welcomed treatment for countless patients.

The functions of Anastrozole go well beyond its anti-estrogenic nature; in fact, this AI has the ability to directly promote testosterone production. First and foremost, by inhibiting testosterone from being aromatized, this will allow more of the testosterone entering the body to remain active. Men who are on testosterone treatment and who need Anastrozole often see their testosterone levels enjoy an approximate 20% upward increase when the AI is added to the equation.

Anastrozole also has the ability to increase testosterone levels due to its ability to stimulate two primary gonadotropins in Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). These are two hormones that are released by the pituitary gland that when released signal to the testicles to make testosterone, LH being primary. For this reason, some physicians will treat their low testosterone patients with Anastrozole only in an effort to remedy the condition. Unfortunately, this protocol rarely works efficiently. The total increase in testosterone is often not enough to bring the individual to optimal testosterone levels. Further, if the individual suffers from primary hypogonadism, he more than likely already produces adequate amounts of LH and FSH; adding more will not help with the problem.

Side Effects:

There are several possible side effects of Anastrozole. Overall, this is generally a very well tolerated AI, but individual response will dictate quite a lot. Most people will not have an issue with responsible use, but due to the individualistic nature of men some will not be able to use it. The most common side effects of Anastrozole are weakness and fatigue. This is normally due to taking too much. When estrogen levels go too low, this will drain the individual. With minimal doses, only what is needed in conjunction with testosterone therapy, there is no logical reason for weakness or fatigue to be an issue. Unfortunately, for the breast cancer patient, much higher doses of Anastrozole are often needed and without the use of testosterone; weakness and fatigue are almost inevitable but worth the trade off when it can save your life.

Beyond weakness and fatigue, the side effects of Anastrozole may include headaches in poor responders, but most will adapt once a little time has passed. Hot flashes are also possible as is high blood pressure although somewhat rare. Joint pain is also a possibility when serum estrogen levels are bottomed out, but this should not occur with proper testosterone therapy. Depression, nausea and vomiting are also possible listed side effects of Anastrozole, but they are extremely rare.

The final possible side effects of Anastrozole revolve around cholesterol. Like all AI’s Anastrozole has the ability to negatively affect lipids; however, it doesn’t appear to have a dramatic or statistically significant effect when used alone. This can, however, change when its use is conjoined with testosterone. Studies have shown that the use of testosterone in moderate doses, even moderate supraphysiological doses will have only a slight affect on cholesterol if any at all. However, when an AI is added it can cause a 20%+ reduction in HDL cholesterol (good cholesterol). This does not mean it will, but it can. In order to afford protection and keep yourself healthy, a healthy lifestyle is the best thing you can do for yourself, which should apply with or without Anastrozole. Diets that are rich in omega fats, low in saturated fats and simple sugars as well as conjoined with regular cardiovascular activity will protect your cholesterol more than anything else.

Doses & Administration:

In the treatment of low testosterone, Anastrozole doses will normally fall in the 0.5-1mg 1-2 times per week range. In most cases, this is enough to keep estrogen under control with 0.5mg 1-2 times per week being the most common dose of all. There are those who will need more, such as 1mg three times per week or who are prescribed to take it as needed, but they are a small minority. Remember, too much Anastrozole will lower your estrogen levels substantially, which can come with a host of problems, such as severe fatigue, joint pain, erectile dysfunction, loss of libido and even a severely weakened immune system. Too much Anastrozole is never a good thing; it should only be used as needed and as little as needed.

Note –  Anastrozole is taken orally and comes in 1mg strength.

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