hormone replacement therapy side effects

The 4 Hormone Replacement Therapy Side Effects to Consult Your Doctor About

by Charlotte

When you begin taking a new medication, it is common to become acutely aware of unexpected changes in your body. After all, many medications have profound physiological effects that can cause everything from temporary discomfort to dangerous side effects. And despite the efforts of doctors and pharmacists to educate their patients on the side effects of drug therapies, it’s impossible to predict how a medication will interact with each person’s body. As a result, patients are often left wondering whether their side effects are normal or cause for concern.

If you’ve recently started traditional hormone replacement therapy (HRT), experiencing side effects can be stressful, and it can be difficult to know when you should talk to your doctor. After all, most hormone replacement side effects like breast tenderness, acne, and nausea are typically harmless and often temporary. However, there are a few side effects both men and women taking HRT should consult their doctors about as soon as possible. There may also be ways to minimize your risk of experiencing these side effects by choosing safer formulations, dosages, and administration methods.

4 Potentially Dangerous Hormone Replacement Therapy Side Effects

Many patients find that traditional HRT has extraordinary benefits, allowing them to recapture their sense of well-being in the face of hormonal changes or disorders. However, some hormonal therapies have side effects that may signal serious medical conditions and warrant a doctor’s consultation. The primary symptoms to watch for are:

  • Sudden and severe headache
  • Slurred speech
  • Blurry or dim vision
  • Dizziness, shortness of breath, or fainting

These side effects are rare, although the risk is generally higher if you started HRT later in life and increases the longer you are on HRT. More importantly, you shouldn’t ignore them for any period of time; if you experience, these side effects, it’s critical to notify your practitioner  to ensure that your health is not compromised.

The underlying pathology that unites all of these symptoms is blood clotting. According to a systematic review of 19 randomized clinical trials examining women taking HRT, HRT increases your risk of developing blood clots by anywhere from two to five times the normal rate. However, the data is not consistent and there is evidence that the risk depends on both which hormones are used and the method of administration; research suggests that progestin and estrogen therapies have different risks, and transdermal estrogen is significantly safer than oral estrogen.  Researchers have also found that testosterone-based HRT products for men may be associated with a greater likelihood of blood clots, although the risk does not appear to remain stable over time. In one recent study, men taking testosterone therapy were 63% more likely to develop venous thromboembolism in the first six months of treatment, after which the risk progressively declined.

Although the increased risk can seem daunting, you are still highly unlikely to experience blood clots as a result of HRT. For example, the 63% increase in venous thromboembolism corresponds to only an additional 10 cases of thromboembolism per 10,000 patients each year, and men over 60 appear to be more likely to be affected. Additionally, the evidence is not conclusive; previous research with different methodologies has not found a relationship between testosterone therapy and blood clots. Nonetheless, it is important to be aware of any potential complications so that you can exercise caution, and people who have existing clotting disorders are particularly vulnerable and may be advised against HRT altogether. As such, it is important to discuss your concerns and potential risk factors with your practitioner prior to initiating treatment. However, some people are unaware that they have a clotting disorder due to an absence of overt symptoms and may take HRT without knowing that they are at added risk. Because blood clots may result in serious health crises, it is crucial to be on the lookout for early symptoms.

Sudden Headache

Sudden headaches can be caused by several different mechanisms of HRT, most of which are innocuous. However, sudden and severe headaches may also be caused by a blood clot. If the headache is caused by a blood clot, it will likely be accompanied by blurred vision. Furthermore, patients will find that these headaches do not respond to over-the-counter pain medications. In this context, blood clots can be life-threatening, and you should seek medical attention immediately.

Other headaches have a more benign explanation, such as dips or spikes in hormone levels. These headaches can sometimes reach the magnitude of a migraine, which means that they often entail altered vision and halos around light sources. Luckily, patients can usually treat hormone-induced headaches with over-the-counter pain medications. However, there’s no single clinical sign that patients can use to differentiate a hormonal headache from a headache caused by a blood clot, so patients need to check with their doctor to find out the exact cause.

Blurry or Dim Vision

Sudden vision impairment, like blurriness or dimness, can be a frightening experience. However, these vision impairments may potentially be the result of a handful rare of hormone replacement therapy side effects, most of which are benign. The most likely cause of vision issues during HRT is hormone-induced deviations of the fluid pressure in your eyes, which can lead to disturbances of vision. These changes are relatively harmless and do not warrant any major medical intervention, although patients may need to take eye drops or refrain from using contact lenses. But there is also the chance that blurry or dim vision could be caused by something more serious.

Altered cardiac tissue output and the increased risk of major blood clots are critical side effects of hormone replacement therapy which may cause blurry or dim vision due to insufficient oxygenation. While it’s highly unlikely, blurry vision or dim vision could preface an oxygenation crisis where you to lose consciousness. It’s also possible that blurry vision could be a non-emergent result of several smaller clotting events. Both of these situations require medical intervention.

Because there’s no way to know with confidence whether your blurry or dim vision is caused by hormonal fluctuations or a serious blood clotting event, you’ll need to talk to your doctor to identify the cause of your vision impairment.

Slurred Speech

One of the most serious symptoms to be aware of when taking HRT is slurred speech, as it may be a sign of stroke. Women taking HRT are unlikely to experience a stroke without having additional risk factors like smoking, obesity, or taking medications that affect blood clotting. However, research suggests that estrogen-only and combined HRT are both associated with is an increased risk of ischemic stroke (caused by blood clots) and hemorrhagic stroke (typically caused by high blood pressure). The risk may be particularly high if you started HRT five or more years after menopause and if you take oral HRT. Significantly, a number of studies have found that transdermal and vaginal HRT were not associated with a higher risk of stroke, and some suggest that these administration routes may actually offer protective benefits.

Currently, there is no consensus on the effect of HRT on stroke risk in men. While some studies indicate that testosterone therapy increases risk, others have found no association or found that testosterone therapy may protect against stroke in men with low testosterone. Additionally, some data suggest that risk depends on method of administration, with men using injectable testosterone experiencing a higher rate of stroke than men using patches or gels. Nonetheless, the U.S. Food and Drug Administration (FDA) requires that manufacturers of all prescription testosterone products include a warning about possible increased risk of stroke.

Regardless of whether a stroke is linked to HRT, slurred speech requires immediate attention. Do not ignore this symptom under any circumstances.

Dizziness, Shortness of Breath, or Fainting

Dizziness, shortness of breath, and fainting are all potential symptoms of blood clots due to HRT. Small blood clots in your lungs and chest may also cause moderate chest pain. You should reach out to your doctor if you experience these symptoms, but be aware that they may not be as scary as first seem. Your body routinely breaks down microscopic blood clots used to repair imperceptible injuries and with a little help from your doctor, you can often be back to normal without any invasive procedures.

Hormone replacement therapy side effects can also include alterations to the output of your cardiac tissue, which could potentially lead to dizziness or fainting in some patients. These symptoms may be consistent for as long as you are on HRT, or they may fade with time as your heart compensates. If your doctor determines that your symptoms are caused by HRT, you will probably undergo a few tests and be advised to start performing more cardiovascular exercise to compensate.  

Knowing When To Reach Out—and Who to Reach Out To

If you experience any of the above side effects, it’s critical to talk to your doctor. As always, if you’re extremely uncomfortable as a result of the sudden onset of side effects, go to the emergency room as soon as possible. With HRT, there’s only a very slim chance that you’ll experience side effects of that magnitude, but it’s better to be safe than sorry.

If you are wondering whether to continue traditional HRT in light of these risks, it’s important to know there may be safer formulations, dosages, or administration methods that will allow you to benefit from hormone replacement while minimizing risk. For example, many patients feel more comfortable using bioidentical hormone replacement therapy (BHRT) due to the potential for more precise dosing, versatile administration methods, and potentially lower risk of side effects. There may also be treatments available to address the side effects you are experiencing or, potentially, the underlying pathology that is making you vulnerable to those effects.

In order to receive the most appropriate care and ensure the best outcomes, it’s critical that you work with a highly-trained hormone replacement therapy expert, such as the practitioners in the BodyLogicMD network. These practitioners can create a personalized plan that’s right for your individual situation based on the latest research in the field. With the right guidance, you can ensure you get the treatment you need in order to protect your health and get the results you want.

If you are looking for expert guidance on hormone replacement therapy, BodyLogicMD-affiliated practitioners can help. The practitioners within the BodyLogicMD network are among the top medical professionals in the nation and specialize in helping patients find wellness through hormonal therapies. By taking an integrative approach to treatment, practitioners within the BodyLogicMD network will work with you to achieve your health goals and give you the resources you need to thrive. Get started on a customized treatment plan designed to fit your lifestyle and help you reach optimal wellness. Begin your journey, contact a local practitioner within the BodyLogicMD network to schedule your first appointment, or take our Hormone Balance Quiz today.

Disclaimer: These statements have not been evaluated by the Food and Drug Administration. All content on this website is for informational purposes only. The content is not intended diagnose, treat, cure, or prevent diseases.


  • Charlotte

    Charlotte is a patient care coordinator specializing in bioidentical hormone replacement therapy. She is committed to helping patients who struggle with the symptoms of hormonal change and imbalance explore their treatment options and develop effective strategies to optimize wellness.