What Are Aromatase Inhibitors?
Aromatase is an enzyme responsible for a key step in the production of estrogens in both men and women. Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when using external testosterone. They may also be used for chemoprevention in high risk women.[1]
How Do Aromatase Inhibitors Work?
Aromatase inhibitors lower estrogen levels in the body by blocking aromatase, an enzyme that converts other hormones into estrogen. This is especially important for men who are using exogenous testosterone or other anabolic steroids that “aromatise.” The majority of estrogen in the male body is a breakdown product of testosterone. When men take testosterone injections they run the risk of increasing estrogen levels as well.
Why Would Men Want To Take Aromatase Inhibitors?
The majority of estrogen in the male body is a breakdown product of testosterone. Other sources and production of estrogen in men include the Leydig Cells in the testicles, adrenal glands and peripheral tissues (adipocytes: fat cells).
Men with naturally low levels of testosterone and who use exogenous testosterone are subject rises in estrogen levels. The more testosterone that is administered into the body means that there is more testosterone available that can be converted into estrogen. This is especially true in obese males who have significant amount of fat cells that house aromatase. Men who are obese tend to have higher estradiol levels than men of normal weight. Elevated estrogen levels can stimulate male breast enlargement (gynecomastia). As men age testosterone production declines and the ratio of estrogen to testosterone rises in favor of estrogen. It is often the ratio and balance of estrogen to testosterone that affects male physiology.[2]
The use of aromatase inhibitors, (Arimidex or Anastrozole) can stop this conversion and breakdown of testosterone. Arimidex has been used in coordination with TRT in many men’s health testosterone clinics to reduce the breakdown of testosterone, reduce estrogen production and as a treatment for gynecomastia.[2]
The Top 2 Aromatase Inhibitors For Men
1. Exemestane (Aromasin)
I’m putting Aromasin first on this list because I personally feel that it is a much better aromatase inhibitor for men who are going to be using it for long term use. One of the benefits to taking Aromasin over Arimidex is that Aromasin will not have a major impact on your cholesterol profile where Arimidex will.
Dosage
Aromasin usually comes in 25mg tablets and how much you should take depends on how well you respond to this medication and how much exogenous testosterone you’re taking. A typical dose taken for men who are on a TRT protocol would be 12.5mg taken 2x per week.
A general rule of thumb that I’ve personally found to be true is that you should take 25mg per every 250mg of testosterone taken weekly. For example if you’re taking 500mg of testosterone per week then you would want to take 50mg of Aromasin weekly. You would split the dose over 2-3 days.
You should always monitor your blood work to make sure that your estrogen levels are within range. Managing estrogen is one of the hardest parts of TRT and will most likely need a few adjustments before getting it right. If you don’t keep your estrogen levels in check it can lead to bloat, fat gain, irritability, mood swings, and can lead to gynecomastia..
Side Effects
Possible side effects of Aromasin are:
- Bone and joint pain
- Hot flashes
- Fatigue
- Headache
- Insomnia
- Increased sweating
- Nervousness
- Dizziness
- Dry skin
- Diarrhea
- Vision changes
- Hair changes
2. Anastrozole (Arimidex)
Arimidex (anastrozole) lowers estrogen levels in postmenopausal women, which may slow the growth of certain types of breast tumors that need estrogen to grow in the body.
Arimidex is used to treat breast cancer in postmenopausal women. It is often given to women whose cancer has progressed even after taking tamoxifen (Nolvadex, Soltamox).
Arimidex is also used to help manage estrogen levels in men who are taking testosterone.
Dosage
Arimidex usually comes in 1mg tablets and like Aromasin the amount that you will need to take will vary based on how well you respond to the medication and how much testosterone you’re taking.
A typical dose taken for men who are on a TRT protocol would be 0.5mg taken 2x per week for a total of 1mg per week. The general rule of thumb here is 1mg of Arimidex per every 250mg of testosterone.
You should always monitor your blood work to make sure that your estrogen levels are within range. Managing estrogen is one of the hardest parts of TRT and will most likely need a few adjustments before getting it right. If you don’t keep your estrogen levels in check it can lead to bloat, fat gain, irritability, mood swings, and can lead to gynecomastia.
Side Effects
Possible side effects of Arimidex are:
- Weakness
- Hot flashes
- Numbness or tingly feeling in your skin;
- Swelling in your ankles or feet;
- Joint pain or stiffness, problems with your fingers while gripping;
- Sore throat
- Headache
- Back pain
- Bone pain
- Depression
- Mood changes
- Sleep problems (insomnia);
- High blood pressure (severe headache, blurred vision, pounding in your neck or ears)
- Nausea, vomiting
- Mild rash
- Negative effects on cholesterol profile
Conclusion
Aromasin and Arimidex are both very effective aromatase inhibitors for men to help manage estrogen levels while taking exogenous testosterone. Which one works best for you will have to be determined by you and possibly your doctor. It might take a couple of months of experimenting to figure out the right dosage but it’s worth the investments to make sure you get it right. The rule of thumb for Aromasin is 25mg per every 250mg of testosterone. The rule of thumb for Arimidex is 1mg per every 250mg of testosterone. I personally prefer Aromasin to Arimidex since I’ve found the right dose to minimize side effects and keep my blood work looking good.
Sources
- https://en.wikipedia.org/wiki/Aromatase_inhibitor
- https://www.regenxhealth.com/post/how-to-manage-estrogen-levels-in-men-on-testosterone-replacement-therapy-trt
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