Understanding the Side Effects of Estrogens, Esterified/Methyltestosterone

Every medication comes with potential side effects, and Estrogens, Esterified/Methyltestosterone is no exception. This combination hormone therapy — which pairs Esterified Estrogens with Methyltestosterone — is prescribed for moderate to severe menopausal hot flashes and night sweats when estrogen alone hasn't been enough. Knowing what to expect can help you tell the difference between normal adjustment symptoms and warning signs that need your doctor's attention right away.

What Is Estrogens, Esterified/Methyltestosterone?

Esterified Estrogens/Methyltestosterone is a combination of two hormones: an estrogen and an androgen (synthetic testosterone). It's available as a generic tablet in two strengths — full strength (1.25 mg/2.5 mg) and half strength (0.625 mg/1.25 mg). Brand names have included Estratest and Covaryx, though most prescriptions today are filled with the generic version (commonly called EEMT). For a deeper look at what this medication is and how it works, see our complete guide.

Common Side Effects

These side effects are relatively frequent and usually mild. Many improve within the first few weeks as your body adjusts to the hormones:

• Breast tenderness or swelling — One of the most common effects of estrogen therapy. Usually decreases over time.
• Nausea, vomiting, stomach cramps, or bloating — Taking the tablet with food may help.
• Headache or dizziness — Typically mild and temporary.
• Acne, increased facial hair growth, or oily skin — These androgenic effects come from the Methyltestosterone component. They tend to be mild at the half-strength dose.
• Weight changes — Some women gain weight, others lose it. Fluid retention is a common contributor.
• Changes in libido — Testosterone can increase sex drive, which is sometimes a welcome effect, but it can also swing the other direction.
• Vaginal itching or discharge — Usually mild and manageable.
• Breakthrough bleeding or spotting — More common in the first few months, especially with cyclic dosing.
• Darkening of facial skin (melasma) — Sun protection can help prevent this.
• Depression, anxiety, or mood swings — Hormone therapy can affect mood in either direction.
• Contact lens intolerance — Hormonal changes can alter the shape of your eyes slightly.

Serious Side Effects — When to Call Your Doctor

This medication carries a boxed warning — the FDA's most serious safety alert. The Women's Health Initiative (WHI) study found increased risks with estrogen-containing hormone therapies. Call your doctor immediately or go to the emergency room if you experience any of the following:

Blood Clots

• Sudden leg pain, swelling, warmth, or redness (signs of deep vein thrombosis)
• Sudden shortness of breath, chest pain, or coughing up blood (signs of pulmonary embolism)

Heart Attack

• Chest pain or pressure, pain spreading to your arm or jaw, nausea, sweating, or shortness of breath

Stroke

• Sudden numbness or weakness on one side of the body, trouble speaking, sudden severe headache, vision changes, or loss of balance

Liver Problems

• Yellowing of the skin or eyes (jaundice), dark urine, severe abdominal pain, unusual fatigue
• Methyltestosterone can cause liver damage, including rare but serious conditions like peliosis hepatis (blood-filled cysts in the liver) and liver tumors

Virilization (Masculinizing Effects)

• Deepening of the voice, male-pattern hair loss, or enlargement of the clitoris
• If you notice early signs of virilization, contact your doctor. Some of these changes may not be reversible if the medication isn't stopped promptly.

Other Serious Concerns

• Breast lumps or changes — Long-term estrogen use is associated with increased breast cancer risk
• Abnormal vaginal bleeding — Could indicate endometrial problems
• Severe allergic reaction — Rash, hives, swelling of the face/throat, difficulty breathing
• Vision changes or sudden loss of vision
• Hypercalcemia — Excessive thirst, frequent urination, confusion, bone pain (especially in women with breast cancer or bone metastases)

Side Effects in Specific Populations

Women Over 65

The Women's Health Initiative Memory Study (WHIMS) found increased risk of probable dementia in women 65 and older taking estrogen-containing therapies. This medication should be used at the lowest effective dose for the shortest time possible, especially in older women.

Women with Liver Conditions

Esterified Estrogens/Methyltestosterone is contraindicated in severe liver disease. Both hormones are processed by the liver, and Methyltestosterone in particular can cause hepatotoxicity. Women with mild-to-moderate liver impairment should be monitored closely.

Women with Diabetes

Estrogens can affect blood sugar control, and Methyltestosterone may increase hypoglycemia risk. If you take insulin or oral diabetes medications, your doctor may need to adjust your doses. Monitor your blood glucose more frequently when starting this medication. See our guide on drug interactions for more details.

Women with a History of Blood Clots

If you have a personal or family history of deep vein thrombosis, pulmonary embolism, or clotting disorders (like protein C, protein S, or antithrombin deficiency), this medication may not be safe for you. Your doctor should evaluate your clotting risk before prescribing.

How to Manage Side Effects

Many common side effects can be managed with simple strategies:

• Take with food to reduce nausea and stomach upset
• Wear sunscreen daily to prevent melasma (skin darkening)
• Use oil-free skincare products if you develop acne from the testosterone component
• Stay hydrated and monitor weight — some weight gain may be fluid retention
• Keep a symptom diary to track what you're experiencing and when. This helps your doctor make adjustments at your follow-up.
• Don't stop abruptly without talking to your doctor. They may adjust your dose, switch to the half-strength formulation, or change your dosing cycle.

If side effects are significantly affecting your quality of life, don't just tough it out — talk to your doctor. Adjusting the dose or switching to an alternative therapy might be the right move.

Final Thoughts

Esterified Estrogens/Methyltestosterone can be very effective for menopausal symptoms that haven't responded to estrogen alone, but it's important to know what to watch for. Most common side effects are manageable and tend to improve with time. Serious side effects are less common but require immediate attention. Regular follow-up visits — typically every 3 to 6 months — allow your doctor to monitor for problems and ensure the benefits continue to outweigh the risks. If you have questions about your symptoms, don't wait for your next appointment — call your doctor's office. And if you need help finding or affording this medication, Medfinder can help.