Understanding the side effects of HRT

Like other medications, hormone replacement therapy (HRT) can cause side effects. While most are mild and resolve naturally with time, some may carry more serious risks—ones your doctor will discuss with you before starting treatment. 

It’s also worth remembering that not every woman will experience the same side effects, and symptoms can differ based on factors like age and existing medical conditions.

Read on as we cover common side effects of HRT, how risk varies across treatment options, and what alternatives your doctor might suggest. 

What’s HRT?

HRT is a treatment that replaces estrogen and sometimes progesterone. Women commonly use HRT during perimenopause and menopause because in this life stage, estrogen and progesterone levels naturally rise and fall. These hormones play many roles in women’s bodies, which is why fluctuations during menopause can cause lots of different symptoms, including: 

• Night sweats
• Vaginal dryness
• Insomnia
• Mood instability
• Needing to urinate urgently and more often

Common HRT side effects

You may experience side effects as your body adapts to treatment. Your doctor will walk you through the risks specific to you, but generally, they include: 

• Diarrhea
• Headaches
• Nausea
• Vaginal bleeding
• Breast tenderness
• Mood instability

Factors that may influence your risk of side effects include dosage, treatment type, and treatment duration. While most side effects typically improve within three months, individual responses vary. Tell your doctor if you experience any unexpected or worsening symptoms. 

Note: Side effects can overlap with perimenopause and menopause symptoms. This can make it tricky to know whether what you’re experiencing is a response to treatment or part of your body’s natural transition. If you have concerns, talk to your doctor—they’ll work with you to identify and address the underlying cause of your issues. 

Other risks to be aware of 

While rare, HRT can sometimes carry more serious health risks. These include an increased chance of developing:

• Gallbladder disease
• Uterine cancer
• Blood clots

Not everyone is at the same level of risk—your medical history and current health play a big role in how likely you are to experience these conditions. For most women, HRT is safe and effective when prescribed appropriately. 

‍Note: In 2025, the FDA updated its guidance on HRT and removed several warnings from black box medication labels after concluding that researchers had previously overstated the risk of certain conditions. These include cardiovascular disease, breast cancer, and dementia. 

Types of HRT and how they influence side effects

There are several ways to take HRT, and each method has its own side effect risks. 

Estrogen therapy vs. combined estrogen-progesterone therapy (EPT)

There are two main types of HRT: 

• Estrogen therapy (ET): Doctors only prescribe ET to women who’ve had a hysterectomy. That’s because taking estrogen alone can thicken the lining of the uterus, raising the risk of endometrial cancer.
• Combined estrogen-progesterone therapy (EPT): Combination therapy delivers both estrogen and progesterone. The progesterone counteracts estrogen's effect on the uterine lining. 

In terms of side effects, progesterone and estrogen therapy can cause several of the same symptoms as estrogen therapy, including headaches, diarrhea, and breast tenderness. 

Continuous combined HRT vs. sequential HRT 

Sequential HRT and continuous combined HRT are common treatment schedules:

• Continuous combined HRT: You take both estrogen and progesterone routinely, usually once a day. 
• Sequential HRT: You take estrogen routinely (typically daily), but only take progesterone during part of the month—often half. 

Sequential HRT can lead to monthly vaginal bleeding in response to progesterone withdrawal. Continuous combined HRT doesn’t usually cause routine bleeding, but breakthrough bleeding can occur while the uterine lining gets used to the treatment. 

Vaginal bleeding on HRT: When to speak with your doctor 

Women who experience withdrawal bleeding on sequential HRT typically see this at the end of each progesterone cycle. On continuous HRT, irregular bleeding is common in the first four to six months. If you notice unexpected bleeding at any point (including heavier bleeding than usual), speak with your doctor as soon as possible, as this can rarely be a sign of underlying issues like endometrial cancer 

Local HRT vs. systemic HRT

There are two ways to administer HRT:

• Local HRT: This treatment delivers hormones directly to a specific area, typically vaginal tissues. It comes in the following forms: rings, tablets/suppositories, patches, creams.
• Systemic HRT: Rather than targeting just one area, this treatment affects the entire body, delivering hormones into the bloodstream. It comes in the following forms: pills, gels, sprays.

Since systemic HRT enters the bloodstream, it passes through the liver, triggering your body to produce more blood-clotting proteins. If you’re at high risk of blood clots, doctors will likely recommend an HRT treatment that’s absorbed through the skin, where the risk of side effects is typically lower. This is because doses are lower, and the medication only treats a small area, so less of it gets into the rest of your body. 

Note: If you experience the symptoms of a blood clot, you should seek emergency medical attention as fast as possible. Warning signs include:

• Pain, redness, or swelling in the legs
• Sudden shortness of breath
• Chest pain
• Coughing up blood

Managing HRT’s side effects

Most HRT side effects are short-lived. You can often expect them to resolve on their own within a few months. The risk of major complications is low when doctors prescribe the right form of HRT and you use it appropriately. 

If you’re experiencing side effects, take these steps:

• Log side effects: Document which side effects you’re experiencing, when they occur, the context around them, and their severity. Your log doesn’t need to be perfect. The goal is to give your provider context to work with. 
• Make lifestyle adjustments: Lifestyle adjustments can go a long way. Take alcohol intake. Excess alcohol may exacerbate various common side effects. Cutting it may be an appropriate step for you. Speak with your doctor about which adjustments make sense for you.

Beyond these, most key steps are clinician-led. Depending on what you’re experiencing and how your body works, your doctor may adjust your treatment plan. Do not make adjustments without their input. 

Who shouldn’t take HRT? 

Some women face a higher risk of complications on HRT. Your doctor may advise against hormone treatment if you have an increased risk of:

• Blood clots
• Gallbladder disease
• Liver disease
• Cardiovascular disease (including stroke and heart attacks)
• Certain cancers (breast cancer, uterine cancer, or ovarian cancer)
• Abnormal vaginal bleeding

HRT also isn’t necessary if you’re pregnant, as the body naturally produces high levels of estrogen and progesterone during this period.

HRT alternatives: Finding what’s right for you

If you can’t or would prefer not to undergo hormone treatment, your doctor might recommend an alternative. These can include:

• Antidepressants: Beyond helping manage mood-related menopausal symptoms, these medications may also help reduce the frequency and severity of hot flashes. Low estrogen can disrupt the brain chemicals like serotonin and norepinephrine that regulate body temperature. Antidepressants rebalance these chemicals.
• Gabapentin: Studies show this antiseizure medication can lower the frequency and intensity of night sweats. The FDA hasn’t approved gabapentin for this use case, but doctors may prescribe it off-label. 
• Herbal remedies: Some research (though limited) points to the potential effectiveness of certain herbal remedies in reducing menopause symptoms. For example, black cohosh might reduce hot flashes, and St. John’s Wort could stabilize mood. 
• Cognitive behavioral therapy (CBT): In addition to mood support, CBT may help alleviate hot flashes by helping you manage your body’s stress responses.
• Lifestyle: Positive lifestyle changes like mindful eating, regular exercise, and quitting smoking can increase your overall health, reducing the impact of many menopause symptoms. 
• Fezolinetant: This nonhormonal prescription medication is used to treat moderate-to-severe hot flashes. It does this by blocking brain signals involved in temperature regulation. 

The role of whole-person care

Hormone care isn’t about prescribing a single solution, whether that’s HRT or an alternative. It’s about understanding root causes and finding the right route forward for you. That’s the approach we take at Maven Clinic: whole-person support.

Maven Clinic's Hormone Care program builds care around your whole health picture, not just the symptom that brought you in. You'll share your symptoms, history, and goals, meet a clinician who knows your story before you start, and get a plan that fits your life — with continuous support and 30+ specialties always a message away between visits.

FAQ

Can I start HRT if I still have periods?

Typically, yes. But the type of HRT your doctor recommends will depend on your health status and where you are in your perimenopause and menopause journey. Continuous combined HRT may not be suitable, as a constant delivery of progesterone can lead to unpredictable or prolonged bleeding if you still have periods.

Will symptoms return if I stop HRT?

Symptoms may return when you stop treatment, as the underlying hormonal changes of menopause persist. However, this depends on several factors, including the phase you’re in. Hormones can naturally stabilize after menopause.

Is HRT safe?

For most women, HRT is safe and effective when prescribed appropriately, especially when started during perimenopause or early menopause. Risk may increase with age, and doctors generally advise not starting HRT over the age of 60 due to the higher risk-to-benefit ratio.

What can I expect when starting HRT?

After starting HRT, it can take three months to notice improvements in perimenopausal or menopausal symptoms, though individual experiences vary. Side effects are most common during this initial period, typically easing as your body adjusts. 

Does HRT interact with other medications?

It can. Interaction risk depends on several factors, including the type of HRT and its administration method. It’s important to tell your doctor all medications you’re taking before starting treatment. 

When should I speak with my doctor about my side effects?

Talk to your doctor immediately about any concerns you have. If a side effect is unexpected or worsening, don’t wait for your next appointment, as it could indicate something more sinister that your doctor needs to know about.

Do side effects mean that HRT isn’t working?

Not necessarily. Some side effects happen because your body is adjusting to the treatment. Speak to your doctor, who will monitor your progress closely and identify the causes of any side effects.