When most people think of hormone replacement therapy for menopause, they think of estrogen, and often estrogen paired with progesterone. That combination is the most common approach, but it isn’t the only one. 

In some cases, progesterone-only therapy is prescribed instead—leaving estrogen out entirely. This guide covers how progesterone-only therapy works and who it’s typically used for.

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What’s progesterone-only therapy?

Progesterone is a hormone your body naturally produces, primarily in the ovaries. It supports menstruation by preparing the uterine lining so it’s ready for a fertilized egg. And if you become pregnant, your progesterone levels rise to help sustain the pregnancy. But progesterone also impacts other parts of the body, including the nervous and cardiovascular systems. 

In menopause, ovarian function declines, and progesterone production drops with it. This can lead to vasomotor symptoms (VMS), vaginal dryness, and mood changes. Doctors may prescribe progesterone-only therapy to supplement declining progesterone levels and help relieve these uncomfortable symptoms. 

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Who should get progesterone-only therapy?

Doctors may recommend progesterone-only therapy if estrogen isn’t a good fit because you’ve had side effects from estrogen or simply prefer not to take it. Your medical history can also rule it out: For people with a history of certain conditions, like breast cancer and stroke, estrogen may raise the risk of complications. 

Progesterone alone also has potential benefits. A 2026 review in Exploration of Endocrine and Metabolic Diseases highlights several:

• VMS relief: Progesterone may reduce the frequency and severity of VMS like hot flashes and night sweats. Researchers propose it may help regulate the neural systems that govern internal body temperature.
• Sleep support: The metabolites of progesterone increase GABA-A receptor activity, which is known to produce a calming effect on the brain and promote sleepiness. That’s one reason why it may increase deep sleep, reduce the time it takes to fall asleep, and reduce waking during the night. 

The researchers note that progesterone’s benefits remain understudied, as it’s often overshadowed by estrogen. Further research is needed to better understand its full efficacy in menopause care.

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Bioidentical progesterone vs. progestins

Progesterone-only therapy comes in two forms, which fall under the umbrella term progestogens. Here’s how they differ:

• Bioidentical progesterone is biologically identical to the hormone your body naturally produces. To be an effective medication, the hormone has been micronized. This process makes the hormone smaller so it can more easily pass through your cells’ membranes. 
• Progestin describes a synthetic, progesterone-like compound that still activates the progesterone receptor and produces similar results. Common options include medroxyprogesterone acetate (MPA), norethindrone, and drospirenone.

The two come in different forms, which can shape which one is prescribed. For example, both are available as an oral medication that can be taken regularly, but progestins also come in other formats, like a hormonal IUD, for people who’d rather not take a pill every day.

Bioidentical progesterone and progestin also differ in the symptoms they help alleviate. While both provide VMS relief, micronized progesterone also helps improve sleep quality. On the other hand, synthetic progestins help protect bone health, which can decline during menopause. Depending on your symptoms and your medical history, your doctor may favor one over the other. 

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Is progesterone-only therapy safe?

Progesterone-only therapy is generally safe when prescribed appropriately. However, you should be mindful of the risks. Here are common side effects of progesterone without estrogen:

• Headache
• Breast pain or tenderness
• Nausea
• Bloating
• Acne
• Irregular vaginal bleeding

Most side effects are mild or moderate. They’re also generally short-lived, easing as your body adjusts to the treatment. Talk to your doctor if you experience severe symptoms or if they don’t alleviate after three months. 

Contraindications

Some health conditions, whether current or in your past, can make certain HRT products unsafe. These are called contraindications. If any apply to you, your doctor will recommend an alternative. 

Take Prometrium®, for example. Bioidentical progesterone is its active ingredient. Here are its contraindications:

• Allergy or hypersensitivity to Prometrium®’s ingredients
• Undiagnosed abnormal genital bleeding
• Breast cancer
• Deep vein thrombosis (DVT) or pulmonary embolism (PE)
• Arterial thromboembolic disease 
• Liver dysfunction or disease

Your doctor will assess all risk factors before prescribing. Have questions along the way? Don’t hesitate to ask. Your peace of mind matters.

Progesterone-only therapy vs. combined therapy

Progesterone-only therapy is just one type of HRT. Combined estrogen-progestogen therapy (EPT) is another, introducing estrogen into the equation. 

Estrogen’s benefits for menopausal women are well established. They include: 

• VMS relief: Estrogen, with or without a progestogen, may reduce hot flash frequency by up to 80%. It may reduce their severity, too.
• Genitourinary syndrome of menopause (GSM) relief: GSM is a collection of genital, sexual, and urinary menopause symptoms. Women taking estrogen report 60–80% improvement in their GSM symptoms.

Various EPT products are FDA-approved as standalone menopause interventions. Progesterone-only products are only approved for menopause when taken alongside estrogen. However, doctors still prescribe progesterone-only products off-label (outside their approved indications) as a standalone menopause intervention, as there’s a growing body of evidence showing how effective they are. 

Here’s a side-by-side breakdown:

*Doctors determine suitability on a case-by-case basis by assessing each individual’s health profile. 

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Understanding the risks of combined therapy

Combined therapy carries risks associated with both estrogen and progestogens. For example, estrogen’s side effects include: 

• Headache
• Breast tenderness or pain
• Nausea
• Diarrhea
• Unexpected vaginal bleeding
• Mood instability
• Leg cramps
• Hair loss
• Mild rash

Estrogen-containing products’ contraindications and warnings also reflect estrogen’s risk profile. Endometrial cancer, for example, is a key estrogen-specific risk. Unopposed estrogen drives the abnormal thickening of the uterine lining (hyperplasia), which can progress to cancer.

Progestogens help regulate endometrial growth, offsetting estrogen’s growth-promoting effects. In a three-year study involving 358 postmenopausal women with a uterus, 64% of those on estrogen-only therapy developed hyperplasia. For those who also took progesterone, this figure dropped to 6%.

This protection is their primary role in combined-therapy regimens. It’s a key reason why doctors prescribe combined therapy for people with a uterus. Estrogen-only therapy may be on the table for those who’ve had a hysterectomy.

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Find the HRT right for you at Maven Clinic

Maven Clinic’s Hormone Care specialists provide personalized, evidence-based support for perimenopause and menopause. Our clinicians review your symptoms, health history, and goals to help you explore treatment options, including hormone therapy when appropriate.

Millions of women, including Alison, trust us with their care:

“Navigating perimenopause has been difficult. I was having symptoms, but my physical and labs came back normal. After speaking with a Maven provider, I felt like someone understood what I was going through and that I wasn’t crazy!”

Discover our approach to hormone care.