EstroGel Side Effects: What to Expect and When to Call Your Doctor

Before starting EstroGel, it's natural to want to know what to expect. Like all medications, EstroGel can cause side effects — some minor and temporary, others that require prompt medical attention. This guide explains what's normal, what to watch for, and when to call your doctor.

The Most Common EstroGel Side Effects (≥5% of Users)

In two well-controlled 12-week clinical trials, the side effects most commonly reported by EstroGel users at a rate of 5% or higher were:

Headache — The most commonly reported side effect. Usually mild and tends to improve as your body adjusts to the new hormone level.

Flatulence (gas) — Estrogens can affect the gastrointestinal tract; bloating and gas are commonly reported in the early weeks of therapy.

Breast pain and tenderness — Very common as estrogen levels rise after a period of estrogen deficiency. Typically decreases within the first 1–3 months of therapy.

Other Common Side Effects

These side effects were not among the top three but have been reported frequently enough to be noteworthy:

Nausea (mild, usually transient)

Vaginal discharge or spotting

Fluid retention (swelling of hands, feet, or ankles)

Application site reactions — skin redness, itching, or rash where the gel is applied (reported in 0.6% of clinical trial participants)

Mood changes — some women notice emotional fluctuations in the first weeks of hormone therapy as levels stabilize

Weight changes — mild weight gain or bloating during estrogen therapy adjustment is possible

Important Safety Note About EstroGel and the FDA's 2025 Label Update

In November 2025, the FDA removed the black box warning from bioidentical transdermal estradiol products like EstroGel. Risks related to cardiovascular disease, cancer, and dementia are now described in the Warnings and Precautions section of the label, rather than as a black box warning. This reflects updated scientific evidence showing the risks were overstated for bioidentical transdermal estradiol specifically, but these risks still exist and should be discussed with your prescriber.

Serious Side Effects: When to Call Your Doctor Right Away

While rare, some side effects associated with estrogen therapy are serious and require prompt medical attention. Contact your doctor immediately or go to the emergency room if you experience any of the following:

Sudden chest pain, shortness of breath, or coughing up blood — possible signs of pulmonary embolism (PE)

Sudden severe headache, vision changes, numbness, or weakness on one side — possible signs of stroke

Leg pain, swelling, or redness — possible signs of deep vein thrombosis (DVT)

Unusual vaginal bleeding — must be evaluated; can be a sign of endometrial changes (important if you still have a uterus)

New breast lumps or changes in your breast — report to your doctor promptly; maintain regular mammograms as scheduled

Jaundice (yellowing of skin or eyes) — may indicate liver dysfunction; discontinue EstroGel and contact your provider

Severe allergic reaction — signs include facial swelling (angioedema), difficulty breathing, or hives; call 911 immediately

Special Warnings: Protecting Children and Others from Accidental Exposure

EstroGel is absorbed through the skin and can affect anyone who touches the application area before it dries. This is particularly important for children — even brief skin contact with the area where EstroGel was applied can cause premature puberty symptoms (breast development, pubic hair growth) in children. After applying EstroGel, always wash your hands with soap and water, and allow the gel to dry completely (about 5 minutes) before covering with clothing. Keep children away from treated skin areas.

Tips for Managing Common Side Effects

Breast tenderness: Often peaks in the first 4–6 weeks and subsides. A well-fitting, supportive bra can help. If it persists beyond 3 months, discuss with your provider.

Headache: Apply EstroGel at the same time each day to maintain consistent hormone levels. Irregular dosing can cause hormone fluctuations that trigger headaches.

Skin reactions: Apply the gel to a different area of the arm each day. Do not apply to irritated, broken, or sunburned skin.

For information on what drugs interact with EstroGel, see EstroGel Drug Interactions: What to Avoid and What to Tell Your Doctor. For a general overview, read What Is EstroGel? Uses, Dosage, and What You Need to Know.