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Anastrozole vs Enclomiphene: Differences and Side Effects

Anastrozole vs Enclomiphene: Differences and Side Effects
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 5 min read

Treatments for low testosterone are bountiful on today’s market. Low testosterone is a problem affecting many men. Roughly 5.6 percent of men suffer from low testosterone. To treat low testosterone, many men turn to Anastrozole and enclomiphene

But what are the differences and side effects of Anastrozole and enclomiphene? 


Anastrozole is a medication used to treat low testosterone. This medication works by reducing the amount of estrogen produced by the body. Although it was originally developed to treat hormone receptor-positive breast cancer, Anastrozole is also used to treat low testosterone in men. However, there is insufficient evidence to prove that this drug is effective. 

Despite this, one study found that Anastrozole increased testosterone levels in older men with hypogonadism. Another study, which analyzed men with infertility and low testosterone, concluded that anastrozole is effective in increasing sperm count and testosterone in certain men.

While Anastrozole has been found effective in treating low testosterone and infertility, it is not effective in treating erectile dysfunction and other sexual function problems. There may be incidences where healthcare providers prescribe Anastrozole off-label for low T. It is usually prescribed in low doses in men who are receiving testosterone replacement therapy (TRT). This medication comes in tablet form and is taken by mouth.

Anastrozole is a “non-steroidal fourth generation aromatase inhibitor” that converts testosterone to estradiol, a hormone that matures and maintains the female reproductive system. 

Anastrozole comes with a number of side effects, which include depression, arthritis, back pain, hot flashes, and bone fractures. According to the Mayo Clinic, Anastrozole can cause other side effects, which include rib and back pain, feelings of warmth, decreased height, and congestion. 

Some of the most common side effects of Anastrozole include the following:

  • Dizziness

  • Blurred vision

  • Nervousness

  • Headache

Less common side effects of Anastrozole include:

  • Chest heaviness or tightness

  • Cough

  • Hoarseness

  • Elevated blood pressure

Anastrozole blocks aromatase, an enzyme used to convert testosterone into estrogen. By slowing down the conversion process, testosterone levels rise. Estrogen levels are consequently lowered. Since many men take testosterone treatments, those who receive TRT in tandem should exercise caution. 

Experts recommend having your estrogen and testosterone levels monitored while taking aromatase inhibitors or AI medications like Anastrozole. However, experts assert that there are many benefits to taking Anastrozole for low testosterone. Research has found that Anastrozole increases sperm quality in aging men with low testosterone. 

Anastrozole has been found to prevent developing conditions, such as fertility problems. Although this medication has many benefits, it also has the potential to cause erectile dysfunction in some men. Experts think this happens because Anastrozole keeps the body from producing estrogen. 

Studies have found that long-term use of Anastrozole can lead to hair loss, liver issues, and increased cholesterol levels. Although cholesterol levels may rise while on anastrozole, you do not need to get treatment for this issue. If high cholesterol runs in your family, you may want to see a doctor about it. 


 But what is enclomiphene exactly? According to experts, Enclomiphene is a medication used to raise serum total testosterone levels in men with secondary hypogonadism. Enclomiphene is used to keep sperm counts at normal levels. This medication significantly increases testosterone levels in men with hypogonadism.

Enclomiphene has been found to be just as effective as topical testosterone and produces increases in LH and FSH levels. LH stands for luteinizing hormone, and FSH stands for follicle stimulating hormone. 

While enclomiphene is very effective, it is important to remember that it also has its own set of side effects. According to experts at RXList, enclomiphene can lead to a high libido, acne, and potentially, a temper.

 Enclomiphene doesn’t have any serious interactions with other drugs. However, it does have moderate interactions with 71 other drugs. Enclomiphene has mild interactions with 101 other drugs. This medication should not be taken by women who are pregnant or breastfeeding. Men who take enclomiphene typically see an increase in testosterone after roughly two weeks of treatment.

Those who take enclomiphene typically see an increase in LH and FSH levels within this period of time. Enclomiphene is relatively safe, and comes with a few side effects. According to experts, enclomiphene can cause hot flashes, nausea, breast tenderness, and stomach pain. You can take Enclomiphene for six cycles. This provides enough time for you to see if the drug is benefitting your body. 

Studies have found that enclomiphene can cause an increase in testicle size, according to the American Urological Association. One drawback of enclomiphene is that it does not provide consistent increases in sperm count, despite evidence that it helps with other aspects of male reproductive health. 

Enclomiphene was not approved to treat secondary hypogonadism in 2007. This happened, because the FDA did not feel increasing testosterone was a good option for a “non-testosterone therapy for hypogonadism,” experts say. You should not take enclomiphene if you are allergic to it or any of its ingredients.

If you are taking other medications or herbs, it is important to check with your doctor before you take this medication. He or she will be able to inform you of any risks or benefits associated with the use of enclomiphene

Be careful not to miss a dose of enclomiphene. You should contact your doctor to get instructions, if you miss a dose of enclomiphene. Be aware that there is a potential for overdose. Seek medical attention immediately if you think you may have overdosed. Drug interactions are different for everyone. Some people may do well with enclomiphene, while others experience a range of side effects.

That’s why it is so important to speak with your doctor about this medication. Doctors recommend that you stop or limit your consumption of alcohol and tobacco while taking this medication. Enclomiphene is not habit-forming. Experts do not know how long this drug remains active in the body. However, enclomiphene has both common and rare side effects. 

Mild side effects of enclomiphene include:

  • Vomiting

  • Nausea

  • Stomach bloating

Enclomiphene has some serious side effects. These include:

  • Breast cancer

  • Retinal bleeding

  • Stroke

Studies have evaluated the effect of testosterone-boosting drugs and found that Anastrozole increases the production of testosterone by stimulating the hypothalamic pituitary axis. Both Anastrozole and enclomiphene inhibit estrogen, while AI drugs reduce levels of estradiol. When used in tandem, experts have found that all of these have positive effects on testosterone levels, leading to better health.

Most men who use these medications find that their testosterone levels return to normal. Different people experience different results when taking these medications. Some people may see an increase in testosterone, while others may see a decrease. No one is exactly the same, and everyone reacts differently.

Because of this, it may be helpful to speak with your healthcare practitioner prior to taking either of these medications. While both of these medications produce the same results, the way each drug works is different. 

Anastrozole starts reducing levels of estrogen as soon as you start taking it. However, it can take weeks to months for Anastrozole to work at full capacity. Men who take Enclomiphene typically see a significant increase in testosterone levels after taking enclomiphene for two weeks.   

Enclomiphene is antiestrogenic and goes by the brand names Androxal and EnCyz. While enclomiphene is very effective, you will not feel its effects until you have been taking it for two to three months. At this point, enclomiphene will hit full capacity and will increase testosterone levels. You may not feel these effects immediately, but be on the lookout for acne and an increased libido. 

As a selective estrogen receptor antagonist, enclomiphene “antagonizes receptors in the pituitary gland, according to Wikipedia. This increases the secretion of gonadotropin. Enclomiphene is different from Anastrozole in the sense that it is a single isomer with estrogen antagonism. 

Enclomiphene improves hormone levels to the point that sperm counts improve. Randomized studies have validated Enclomiphene’s success in raising testosterone levels in men. When compared to other treatments, enclomiphene helps hypogonadal men maintain fertility, while improving testosterone levels. 

Enclomiphene works differently than other methods of testosterone therapy. According to experts, enclomiphene triggers the body to produce its own testosterone, while methods like TRT replace natural testosterone with synthetic testosterone

Anastrozole is different in the sense that it is made by a number of manufacturers under different names. Some manufacturers add extra ingredients into the medication, so different brands may not be exactly the same. While Anastrozole is efficient in treating low testosterone in hypogonadal men, anastrozole can at times, cause problems. 

If you want to avoid any negative side effects, it is important to set up a treatment plan with a medical professional. Your doctor may not be able to tell you how the drug will affect you ahead of time. However, he or she can make sure you’re informed of the possible consequences of taking Anastrozole or one its name brands.

It is also important to do your research. Research any medications you are taking to see if they interact with either of these drugs. 



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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.