What Is Hormone Replacement Therapy (HRT)—and Do You Need It?

Medically reviewed by Kelly Wood, MD

Hormone replacement therapy (HRT) is a treatment that involves taking hormones to replace depleted estrogen, progesterone, or testosterone levels in your body. 

An obstetrician-gynecologist (OBGYN)—a doctor who specializes in the female reproductive system—will use HRT to relieve menopause symptoms by providing estrogen and/or progestin (synthetic progesterone). A primary care provider or urologist—a doctor specializing in the urinary tract—will also use HRT to replenish low testosterone levels.

Purpose

Hormone replacement therapy helps relieve symptoms related to hypogonadism, which occurs when the sex glands produce too little or no sex hormones. In people assigned female at birth (AFAB), HRT can help relieve symptoms of menopause and perimenopause—like vaginal dryness, night sweats, and hot flashes. 

In assigned males at birth (AMAB), HRT can help treat symptoms of hypogonadism like low sex drive, sexual dysfunction, and low muscle mass. Male hypogonadism occurs when the testes produce too little or no testosterone. This is more common in males as they age and testosterone levels naturally drop.

In rare cases, a healthcare provider may prescribe hormone replacement therapy to help initiate puberty, treat infertility, and prevent osteoporosis (a common bone condition) in postmenopausal people.

Types of Hormone Replacement Therapy

There are different hormone replacement therapies available based on your sex. Depending on your specific needs, your healthcare provider will prescribe you hormones in the form of pills, sprays, skin patches, topical creams or gels, vaginal rings, or injections.

Estrogen Therapy

This form of HRT only replaces estrogen. Estrogen-only therapy helps treat menopause symptoms in those who've had a hysterectomy—a surgery that removes the uterus. You can receive estrogen therapy via pills, skin patches, topical gels, and vaginal rings, tablets, or creams.

Combined Hormone Therapy

If you still have a uterus, estrogen and progestin (a synthetic form of progesterone) are both taken to help replenish levels. Adding progestin helps decrease the risk of uterine cancer from taking estrogen therapy. You can combine progestin with estrogen in a patch or pill. In some cases, your provider may recommend taking progestin in addition to estrogen as a pill, vaginal tablet, or vaginal gel.

Testosterone Therapy

This form of HRT replaces testosterone levels in AMAB with hypogonadism. Testosterone therapy is typically administered via an oral medication, injection, topical gel, or patch.

How Does HRT Work?

HRT given via pills, injections, skin patches, and topical gels works by releasing hormones into the bloodstream, which travels to other organs and tissues. This helps the body replenish lost or depleted hormone levels. Knowing what to expect before, during, and after the HRT process can help ease any anxiety and answer any questions you may have.

Before Hormone Replacement Therapy

Before you can start HRT, your healthcare provider will need to identify your estrogen and testosterone levels. This will help them ensure you have hypogonadism and figure out the correct hormone dosage that you need. If you are an AFAB, you might also need to check your follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. These tests can also identify menopause or perimenopause. 

During your blood test, your healthcare provider will insert a small needle into a vein in your arm to draw a blood sample. This may be slightly uncomfortable and sting. In less than 5 minutes, blood is collected in a small vial or tube and reviewed in a lab for certain hormone levels. During a testosterone level test, bloodwork is completed between 7 a.m. and 10 a.m because these are the times when testosterone levels peak.

During Hormone Replacement Therapy

Most HRT is painless and can be self-administered (meaning, you can give it to yourself). If you're receiving estrogen-only therapy, you'll need to take estrogen pills daily to help the body replenish hormone levels. You can also apply small doses of estrogen directly to vaginal tissue.

Combined hormone therapy may involve continuously taking estrogen and progestin every day. Your provider may also suggest cyclic therapy or sequential hormone replacement therapy. This form of combined HRT involves taking estrogen daily and then adding a progestin pill for 10-14 days every month.

During testosterone therapy, you'll need to apply testosterone-containing gels or patches daily to your shoulder, upper arms, or abdomen. If your healthcare provider recommends injections, testosterone will be injected into your buttocks muscle via an intramuscular injection. A healthcare provider will administer this injection, or they will teach you how to administer it yourself. Testosterone injection doses and timelines may include:

• 50-100 milligram (mg) doses once a week

• 100-200 mg doses every two weeks

• 750 mg initial dose followed by another dose four weeks later and additional doses every 10 weeks

After Hormone Replacement Therapy

After you administer your own HRT—or see a provider for an injection—you can go about your day as usual. Your provider will continue to monitor your hormone levels with blood tests as needed.

Your provider will likely recheck your hormone levels every 3-6 months. Depending on your unique needs, your provider may also check your levels yearly. Checking your hormone levels can help them decide if you should continue HRT or not.

Risks and Precautions

When treating menopause and perimenopause symptoms, research shows short-term HRT is typically safe—especially if completed before age 60 or within 10 years of experiencing menopause.

Estrogen Therapy Risks

Estrogen can thicken the lining of the uterus, which increases your risk of uterine cancer. If you have a uterus, adding progestin with combined hormone therapy helps decrease this risk. Research shows estrogen HRT may also increase your risk of blood clots, heart attack, stroke, and gallbladder disease. However, these risks are small and typically increase based on factors like age and existing conditions like heart disease, kidney disease, and obesity.

Combined Therapy Risks

Combined hormone therapy may also increase the risk of breast cancer. In fact, this therapy shouldn't be used if you have a history of hormone-sensitive breast cancer. 

Testosterone Therapy Risks

Research on the risks of testosterone replacement therapy is conflicting. Some research has found testosterone therapy increases the risk of heart disease. Other research has found no link between testosterone therapy and heart disease. However, testosterone replacement therapy is not safe if you have a history of prostate cancer, breast cancer, or uncontrolled heart failure.

Those using topical testosterone should also make sure the area they apply testosterone doesn't come into contact with children, pregnant people, or assigned females at birth. Testosterone can lead to early puberty, hormonal disruptions, and potential harm among these demographics. 

Overall HRT Risks

If you are pregnant or think you may be pregnant, stop taking any form of hormone therapy. You should also avoid HRT if you have a history of blood clots, heart attack, stroke, cancer, or liver disease.

Side Effects

It's possible to experience side effects during HRT. Common estrogen and combined hormone therapy side effects include: 

• Spotting or vaginal bleeding

• Sore breasts

• Bloating

• Headaches
  

Testosterone replacement therapy can also cause side effects like:

• Heartburn 

• Headache

• Diarrhea

• Gas

• Breast pain or enlargement
  

If you experience any side effects that affect your quality of life, talk with your healthcare provider and they can adjust your hormone dosage if needed. However, you should call your healthcare provider immediately if you have more extreme side effects, like:

• Severe mood changes

• Swelling

• Nausea or vomiting

• Dark-colored urine

Results and Benefits

Depending on your hormone levels, hormone replacement therapy may take months to years to see results. You will work with your healthcare provider on a custom schedule for blood tests and appointments to determine whether your HRT dosage is working. To reduce your risk of side effects and health risks, healthcare providers typically won't prescribe HRT for more than a few years. 

Research shows taking estrogen and combined hormone therapy can treat hot flashes and night sweats associated with menopause. Estrogen therapy is also effective at relieving vaginal dryness. Non-vaginal estrogen therapies may also help protect against bone loss in early menopause, which can lead to osteoporosis. Studies also show that combined hormone therapy may reduce the risk of colon cancer. 

Testosterone replacement therapy, however, can improve the side effects of male hypogonadism. Research shows that those who took testosterone replacement therapy noticed an improvement in energy levels, bone mineral density, muscle mass, mood, and sexual function.

A Quick Review

Hormone replacement therapy involves taking estrogen, progesterone, or testosterone to help relieve menopause or male hypogonadism symptoms. HRT is typically self-administered in the form of pills, patches, or gels to release hormones into the bloodstream.

While you take HRT, your healthcare provider will do routine blood tests to check hormones and decide if you should continue therapy, as this therapy does come with some risk of certain cancers and other diseases.

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