Testosterone plays a vital role in a range of bodily functions, including muscle and bone health, cognition, red blood cell and sperm formation, and sexual and reproductive function in males.

However, testosterone levels can decline for various reasons, including stress, aging, and certain health conditions, such as hypogonadism.

This article discusses TRT in more detail, including who it is for, the types, how it works, how to get it, what to expect from it, and more.

TRT or androgen replacement therapy (ART) is a treatment that doctors give to males who have testosterone deficiency and are showing symptoms of hypogonadism.

Taking prescription testosterone helps restore the levels of this hormone in the blood, reversing the symptoms of low testosterone. People who take it may notice improvements in alertness, sexual function, energy, mood, and overall well-being.

Who is testosterone replacement therapy for, and how does it work

Doctors prescribe TRT to males with hypogonadism. To receive a definitive diagnosis, blood tests must show that a person has low testosterone levels, which the American Urological Association notes as being below 300 nanograms per deciliter (ng/dl). The individual must also have other symptoms, such as fatigue, breast growth, and sexual dysfunction.

However, doctors do not usually recommend TRT as the first course of action for low testosterone levels, even for males who show such symptoms.

If other conditions or medications cause testosterone levels to drop, doctors usually treat the underlying condition before recommending TRT.

TRT is only available with a prescription. If a person presents with symptoms consistent with low testosterone levels, a doctor will only provide a prescription after taking a thorough medical history and performing physical and lab exams.

As hormone levels fluctuate depending on activity levels, diet, and the time of day, doctors usually take a blood test before noon on 2 consecutive days. They may sometimes also ask for imaging studies and additional tests, such as tests for luteinizing hormone and follicle stimulation hormone, to determine the cause of the low testosterone levels.

There are several ways to administer testosterone:

Injectable

Injectable testosterone is an inexpensive and common form of TRT. A person can receive short-acting treatment, which involves a shot every 1 or 2 weeks, or long-acting treatment, in which the second shot is 4 weeks after the first, and all others are 10 weeks apart. The dosage and frequency of the treatment may vary depending on the person.

Doctors inject short-acting testosterone under the skin or muscle, while long-acting shots go in the gluteal muscles.

TRT can cause fluctuations in testosterone levels, which can affect energy levels, libido, mood, and the presence of symptoms such as breast tenderness.

Topical (transdermal)

People usually apply gels and creams on a daily basis. Gradual absorption causes more stable testosterone levels in the blood.

However, people using topical treatments must be careful to avoid skin-on-skin contact with other people for at least 6 hours after application. It is important to prevent the risk of transferring the medication onto other people’s skin because it may be dangerous for pregnant people and children.

Topical patches stick to the skin and stay in place for 24 hours until the next dose. The downsides to patches are that they are not cosmetically appealing and often cause skin irritations.

Cheek or buccal patches

A person places a buccal patch above the upper teeth, and it releases testosterone over 12 hours. In comparison with oral medications, patches may be less toxic to the liver. However, these patches can cause headaches and gum and mouth irritation.

Testosterone implants or pellets

Testosterone pellets are small plastic pellets that doctors implant under the skin. The implant goes into a person’s upper hip or buttock. The pellets dissolve slowly and can deliver TRT for 3–6 months.

Inserting implants is a minor inpatient surgical procedure. A doctor makes a small cut and then inserts the pellets in the fatty tissue below the skin. They perform the procedure under local anesthesia.

Learn more about testosterone pellets here.

Oral testosterone

Oral testosterone is a less common type of TRT that is more expensive and less practical. Its long-term use can potentially cause liver damage.

Most tablets also come with warnings about the drug causing hypertension and stroke. As a result, only individuals who cannot use other forms of TRT resort to taking testosterone by mouth.

Intranasal

A person applies nasal testosterone gel to the inside of the nose. They will need to do this three times a day at intervals of 6–8 hours, preferably at the same times every day. Some common reactions to this treatment include headaches, nosebleeds, a runny nose, and nasal discomfort.

TRT aims to restore a person’s testosterone levels to normal. The individual can expect improvements in their blood testosterone levels within a week.

A person may also note other benefits, such as an increase in bone density and lean body mass, an improvement in well-being, and a boost to energy and libido. It may take from 4 weeks to several months to see positive changes.

TRT is typically a lifelong treatment. Once a person starts TRT, their doctor will continually monitor their response to treatment. People need to have routine checkups at least every 6–12 months to assess their blood testosterone levels.

A doctor will also monitor changes in symptoms and side effects at 3 and 6 months after the initial treatment and then annually.

TRT costs range from $150 to $1,500 per month and vary depending on various factors, including:

  • type of medication
  • dosage
  • mode of administration
  • insurance coverage
  • doctor and laboratory fees

In addition to the possible short-term side effects, TRT may also cause health risks. The Endocrine Society recommends that people with the following conditions do not start using TRT:

It also states that the treatment is unsuitable for males who wish to conceive in the near future.

Males aged 40 years older, preadolescent people, and those with migraine or epilepsy may require special considerations.

The Food and Drug Administration (FDA) explains that the benefits and safety of TRT for treating low testosterone levels due to aging are not known. The organization requires that testosterone products carry warnings mentioning the possible risk of stroke and heart disease.

A 2017 review found that men undergoing TRT have a higher risk for cardiovascular events such as stroke.

Other side effects of taking testosterone include:

High cholesterol may also be a side effect. However, a 2021 study suggests that TRT may improve total cholesterol levels.

The current scientific literature suggests that TRT worsens breast and prostate cancer. However, TRT may offer benefits to people with early stage prostate cancer without stimulating the recurrence or progression of cancer.

The following are commonly asked questions:

How much does TRT cost?

TRT costs range from $150–$1,500 per month depending on the type of TRT, the mode and frequency of administration, and the insurance coverage.

Does insurance cover TRT?

Yes. Most insurance companies cover all forms of TRT. However, there may be out-of-pocket costs.

Is testosterone replacement therapy safe?

Although TRT offers benefits to people with low testosterone levels, it can cause many short-term side effects. It may also put people who take TRT in the long term at increased risk of liver and heart problems.

How long should I stay on testosterone replacement therapy?

TRT treatment length is indefinite unless the low levels are due to an underlying cause that is treatable.

TRT is a common treatment for low testosterone levels, but it is not suitable for everyone.

People who are considering TRT need a prescription and proper guidance from a doctor.