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Chemical castration is the use of drugs to lower the production of hormones in your testicles.

Doctors use this method to treat hormone-related cancers, such as prostate cancer. Other names for chemical castration are:

  • hormone therapy
  • androgen suppression therapy
  • androgen depressive therapy

Let’s take a closer look at how chemical castration works, what the long-term risks are, and if it can be reversed.

The purpose of chemical castration is to lower the levels of male hormones, or androgens.

The main androgens are testosterone and dihydrotestosterone (DHT). According to a 2012 research review, about 90 to 95 percent of androgens are made in your testicles. The rest come from your adrenal glands.

Luteinizing hormone-releasing hormone (LHRH) comes from your pituitary gland. This hormone tells your testicles to make testosterone.

That’s where LHRH agonists come in. They work by stimulating the production of luteinizing hormone (LH). That’s why when you first take them, LHRH agonists cause testosterone levels to rise.

This effect only lasts a few weeks, though. And taking anti-androgens such as bicalutamide for a few weeks can relieve this concern.

When LH levels are higher, your pituitary gland stops making it. It no longer tells your testicles to make androgens. As a result, circulating testosterone is reduced to very low levels, similar to surgical castration.

About LHRH agonists

Some LHRH agonists are:

  • goserelin (Zoladex)
  • histrelin (Vantas)
  • leuprolide (Lupron, Eligard)
  • triptorelin (Trelstar)

LHRH agonists are also known as gonadotropin-releasing hormones (GnRH) agonists. They don’t directly affect the production of androgens in your adrenal glands, as anti-androgens do.

Treatment is ongoing

Chemical castration is not a one-time treatment. Your doctor administers the drugs by injection or implants them under your skin.

Depending on the drug and the dose, this must be repeated as often as once a month or as seldom as once a year.

For advanced prostate cancer, your doctor may recommend LHRH antagonists instead. They work faster than LHRH agonists, but don’t cause an increase in testosterone levels. Some of these medicines are:

  • degarelix (Firmagon), a monthly injection
  • relugolix (Orgovyx), a daily pill

Side effects of chemical castration can include:

Over the long term, chemical castration may also lead to:

According to a 2013 research review, side effects and complications may increase the longer you’re in treatment. Your doctor may recommend other therapies to prevent or ease these side effects.

Other potential risks

There are also concerns that men treated with hormone therapy may be at an increased risk of:

According to the American Cancer Society, not all studies have reached the same conclusions about these risks. More research is needed to fully understand the relationship between chemical castration and these conditions.

Chemical castration lasts as long as you continue to take the drugs. Once you stop taking them, hormone production returns to normal.

The effects are generally reversible. But if you’ve been taking the medications for a long time, some side effects may continue.

Chemical castration is administered with oral medication, injections, or an implant under your skin. This affects hormone levels, but there’s no immediate change in the appearance of your testicles.

However, they may shrink over time. In some cases, your testicles can become so small that you can’t feel them.

The effects last as long as you stay in treatment. Once you stop, they’re generally reversible.

Surgical castration, also called orchiectomy, is the removal of one or both testicles. It can be considered a surgical form of hormone therapy.

According to the National Cancer Institute, this procedure can lower testosterone in your blood by 90 to 95 percent.

Surgical castration is generally done on an outpatient basis. But once it’s done, it cannot be reversed, so you should consider it permanent.

A procedure called subcapsular orchiectomy involves removing your tissue that produces androgens instead of your entire testicle. This keeps your scrotum intact. If desired, artificial testicles can be inserted into your scrotum.

Chemical castration is used to treat hormone-dependent cancers, such as prostate cancer. Lowering androgens can help slow cancer growth and metastasis.

Chemical castration may be beneficial for prostate cancer that has spread or recurred after first-line treatment.

Prostate cancers tend to be castration-sensitive early on. Over time, they can become castration-resistant, but may still be responsive to:

Chemical castration can also be used to slow the progression of male breast cancer.

Chemical castration for people who are incarcerated for sexual violence

Because it can reduce libido, some countries chemically castrate people who are incarcerated for sexual violence.

A handful of states within the United States have legalized chemical castration for people who are incarcerated for sexual violence. It’s usually used as a condition of parole.

It’s not clear that lowering your sex drive is enough to prevent sexually violent offenses.

Not every person will completely lose sexual function. Chemical castration also relies on long-term compliance, which can be a concern.

Those in the medical profession may also have ethical concerns about overtreatment versus punishment. There are complex concerns related to coercion and potential lack of informed consent.

Whether performed for health reasons or legal ones, there is a need to monitor and treat side effects and complications.

Healthline

Chemical castration is the use of medication to lower levels of male hormones. It has the same effect as the surgical removal of your testicles, except that it’s not permanent.

There are significant side effects to chemical castration, such as:

  • loss of libido
  • hot flashes
  • shrinking testicles

Once you stop the treatment, androgen production should return to normal. But some side effects, such as osteoporosis, can become long-term concerns.

Chemical castration is primarily used to treat hormone-dependent conditions, such as prostate cancer.