Estrogen Blockers for Men: Everything You Need to Know (2023)

Over time, levels of the hormones testosterone and estrogen can become imbalanced in men, potentially causing health problems. Medications called estrogen blockers are among the treatment options for those with low testosterone and higher estrogen.

This article discusses how estrogen functions in men and symptoms of a testosterone and estrogen imbalance. It also covers treatments that block estrogen and when to see a healthcare provider.

Estrogen in Men

Estrogen is often thought of as a female hormone, as the ovaries produce much of the hormone. However, men also have estrogen in their bodies. About 20% of a man's estrogen is produced by the testes. The rest is produced in body fat, the brain, skin, and bones.

Estrogen in the male body impacts many functions, such as:

• Maintenance and growth of bones
• Coordination of head and eye movement to support vision
• The type and location of fat in the body and metabolism
• Sexual functioning in relation to libido (sexual drive), erectile functioning, and the creation of sperm

Symptoms of Estrogen and Testosterone Imbalance

Changes to the ratio of estrogen and testosterone in the body can result in health problems for some people. For example, in people with late-onset hypogonadism, lower testosterone levels and an increase of androgens being converted to estradiol is associated with a number of health issues, including:

• Infertility
• Reduced sex drive
• Reduced muscle mass and energy
• Erectile dysfunction
  
• Hot flashes
• Decreased testicle size
• Gynecomastia (enlarged breast growth)
• Low-energy fractures (where bone fractures occur due to falling from a standing height or less)

Aromatase excess syndrome is a rare genetic condition that results in higher levels of estrogen. It can affect some young men and lead to late childhood developmental symptoms. In addition to breast growth, the associated symptoms include:

• Quicker than normal physical development that stops sooner than others
• Short stature

Estrogen Blockers

Estrogen blockers are a type of treatment that reduces the amount or functioning of estrogen in the body.

Several estrogen blocker medications used to treat the imbalance of testosterone to estrogen were initially developed for use in treating breast cancer in women. However, they have been prescribed for off-label use in male patients.

Medications

Medications used as estrogen blockers include:

• Aromatase inhibitors (AI): This medication can increase testosterone, along with other hormones, by inhibiting the ability of androgens to be converted to estradiol in the body. This decreases the overall level of estrogen in the body. The medication also acts on the hypothalamus and pituitary gland to increase luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the body, which may support healthy sperm. Some available AI medications used for this purpose are anastrazole and letrozole.
• Selective estrogen receptor modulators (SERM): These medications bind to estrogen receptors to prevent estrogens from binding with each other. A similar function of releasing LH and FSH can also be achieved by use of SERM. Common SERM medications used to address the hormonal balance in men include tamoxifin and clomiphene citrate.

Side Effects

Estrogen-blocking medications have been prescribed for off-label use in those with low testosterone for some time and are often well-tolerated. However, there aren't established guidelines for their use in men. More long-term studies are needed to establish efficacy and safety of the medications for this specific purpose.

That said, some research has found these reported side effects:

• AI: In general, AI are well-tolerated by those who use them for this purpose. Side effects may include nausea, increase in liver enzymes, headaches, and hot flashes.
  
• SERM: Researchers have noted that clomiphene citrate has minimal side effects while being able to increase testosterone levels and improve bone mineral density and androgen deficiency. Rare side effects for clomiphene citrate include headaches, changes in vision, and gynecomastia (enlargement of male breasts). Use of tamoxifen may involve more significant side effects, including gastrointestinal upset, risk of blood clots, and cardiovascular problems.
  

Natural Estrogen Blockers

While there is no solid evidence supporting the following as effective estrogen blockers, some proponents believe they can be used for this purpose:

• Maca root: Maca is a cruciferous plant that is found in Peru. It has been touted as an estrogen blocker and fertility enhancer in men, but there is no scientific evidence to support these claims.
  
• Wild nettle root: Wild nettles are leafy shrubs that are purported to contain compounds that act as natural estrogen blockers.
• Chrysin: Chrysin is a flavonoid that can be found in passionflower, honey, and bee propolis. Some research suggests that chrysin may block estrogen, however this has not been confirmed in human studies.
• Grape seed extract: There is some evidence that grape seed extract has been shown to act as an aromatase inhibitor, or estrogen blocker, in post-menopausal women.

Are There Alternatives to Estrogen Blockers?

While research findings are mixed, there is some evidence that testosterone therapy may decrease estrogen levels in men. One 2018 study found that estrogen levels decreased in transgender men who received testosterone therapy.

Strategies to avoid estrogens in the environment (which is a healthy thing to do in general) include:

• Avoiding meat products made from animals raised with synthetic hormones
• Avoiding plastic food containers, plastic water bottles, and plastic wraps. These can leach bisphenol A (BPA), an endocrine disruptor, into food and beverages, especially when heated.
• Avoiding shampoos and other personal care products containing parabens
• Eating lower-fat foods. High-fat diets, especially high-fat dairy products, are linked to excess estrogen production.
• Eating more cruciferous vegetables, such as kale, broccoli, and Brussels sprouts. These vegetables are thought to regulate estrogen.

When to Talk to Your Healthcare Provider

If you are experiencing symptoms associated with an imbalance of testosterone and estrogen, particularly reduced sexual desire and erectile dysfunction, speak with a healthcare provider to help you determine the exact cause. To investigate whether hormones may be at the root of your symptoms, they may do a blood test to measure your hormone levels.

If your hormone levels meet the criteria for a diagnosis such as hypogonadism, they can also advise on treatment options. These can range from changing lifestyle factors (such as sleep and diet) to medications.

Summary

When estrogen levels in men are higher than testosterone levels, estrogen blockers may be needed to restore the balance of these hormones and prevent health problems caused by a rise in estrogen. Most estrogen blockers are well-tolerated, but there are some side effects. If you notice symptoms such as erectile dysfunction, gynecomastia (enlarged breasts), or hot flashes, contact your healthcare provider.