Short answer: In the label's 2-year placebo-controlled study of women 60 to 80, the clearest differences on Menostar were leukorrhea or vaginal discharge (11% vs 1% on placebo), arthralgia or joint pain (12% vs 6%) and cervical polyps (6% vs 2%). The label lists upper respiratory infection, pain, arthralgia and leukorrhea as most common. Menostar carries the estrogen boxed warning on endometrial cancer, stroke, blood clots, dementia and breast cancer.
What Menostar is approved for: Menostar is a low-dose weekly estradiol patch. Its only approved use is to prevent postmenopausal osteoporosis (section 1.1). The label says that when prescribing only for this, non-estrogen medicines are considered first, and estrogen only for women at significant risk of osteoporosis.
Source
MENOSTAR (estradiol transdermal system), prescribing information, Patient Information and Instructions for Use. Bayer HealthCare Pharmaceuticals. DailyMed, version published March 16, 2026. DailyMed setid a78708cd-04d4-4221-a4e4-53680bbe2912
WARNING: ENDOMETRIAL CANCER, CARDIOVASCULAR DISORDERS, PROBABLE DEMENTIA and BREAST CANCER
Estrogen-alone therapy: a woman with a uterus who uses estrogen without a progestogen has a higher risk of endometrial cancer. In the Women's Health Initiative (WHI), daily oral conjugated estrogens (CE) 0.625 mg alone raised the risk of stroke and deep vein thrombosis over 7.1 years, and the WHI Memory Study found a higher risk of probable dementia in women 65 and older. Estrogen plus progestin therapy: CE plus medroxyprogesterone acetate (MPA) 2.5 mg raised the risk of DVT, pulmonary embolism, stroke, heart attack, invasive breast cancer and probable dementia. Neither is to be used to prevent heart disease or dementia. Only those oral doses were studied, so the label says the relevance to other doses, routes or products is not known and the risks cannot be definitively excluded. Estrogens are prescribed at the lowest effective dose for the shortest duration consistent with treatment goals and risks.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Menostar.
| Adverse reaction | Menostar 14 mcg/day (N=208) | Placebo (N=209) |
|---|---|---|
| Upper respiratory infection | 33 (16%) | 35 (17%) |
| Accidental injury | 29 (14%) | 23 (11%) |
| Pain | 26 (13%) | 26 (12%) |
| Arthralgia | 24 (12%) | 13 (6%) |
| Leukorrhea | 22 (11%) | 3 (1%) |
| Application site reaction | 18 (9%) | 18 (9%) |
| Abdominal pain | 17 (8%) | 17 (8%) |
| Cervical polyps | 13 (6%) | 4 (2%) |
| Bronchitis | 12 (6%) | 9 (4%) |
| Infection | 11 (5%) | 10 (5%) |
| Constipation | 11 (5%) | 6 (3%) |
| Dyspepsia | 11 (5%) | 9 (4%) |
| Arthritis | 11 (5%) | 15 (7%) |
| Dizziness | 11 (5%) | 6 (3%) |
| Myalgia | 10 (5%) | 6 (3%) |
| Breast pain | 10 (5%) | 8 (4%) |
2-year placebo-controlled study of 417 postmenopausal women aged 60 to 80 with a uterus. Cells are number of women (percent). Body-system total rows are left out.
Lumbar spine bone density rose 2.29% at 12 months and 2.99% at 24 months on Menostar vs 0.51% and 0.54% on placebo; total hip rose 0.90% and 0.84% vs falls of 0.22% and 0.71% (Table 3). All participants took calcium and vitamin D.
At 24 months the bone effect was about twice as large in women whose starting estradiol was under 5 pg/mL (spine difference 3.21, hip 2.13) as in those at 5 pg/mL or more (1.59 and 0.92) (Table 4).
WHI CE alone vs placebo, per 10,000 women-years: stroke 45 vs 33; VTE 30 vs 22; DVT 23 vs 15. CE plus MPA vs placebo: stroke 33 vs 25; DVT 26 vs 13; pulmonary embolism 18 vs 8.
WHIMS, women 65 to 79: probable dementia 37 vs 25 cases per 10,000 women-years on CE alone (relative risk 1.49), and 45 vs 22 on CE plus MPA (relative risk 2.05).
Reported after approval: bleeding pattern changes, pelvic pain, breast cancer, breast pain and tenderness, blood pressure changes, palpitations, hot flashes, nausea, vomiting, hair loss, night sweats, rash, vision changes, depression, migraine, mood swings, insomnia, headache, edema, weight gain, application site reaction and anaphylactic reactions.
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Who should not use it. Women with undiagnosed abnormal genital bleeding, current or past breast cancer, estrogen-dependent cancer, active or past DVT, pulmonary embolism, stroke or heart attack, a known anaphylactic reaction, angioedema or hypersensitivity to Menostar, liver impairment or disease, or protein C, protein S or antithrombin deficiency or other clotting disorders.
Blood clots, stroke and heart attack. Estrogen alone raised the risk of stroke and DVT; estrogen plus progestin raised the risk of pulmonary embolism, DVT, stroke and heart attack. Treatment is stopped right away if one occurs or is suspected, and if feasible 4 to 6 weeks before surgery linked to clots.
Endometrial, breast and ovarian cancer. Estrogen without a progestogen raises endometrial cancer risk 2 to 12 times in women with a uterus, and unexplained bleeding is checked. CE plus MPA raised invasive breast cancer risk in the WHI, and hormone therapy has been linked to more abnormal mammograms and to ovarian cancer.
Probable dementia. In women 65 to 79, probable dementia was more common on CE alone (relative risk 1.49) and on CE plus MPA (2.05) than on placebo. Whether this applies to younger women is unknown.
Gallbladder, calcium, vision and blood pressure. Estrogens are linked to a 2- to 4-fold rise in gallbladder disease needing surgery (5.4), severe high calcium in breast cancer spread to bone (5.5), retinal blood clots (5.6), rare blood pressure rises (5.8) and high triglycerides with pancreatitis (5.9).
Thyroid, fluid and other conditions. Women on thyroid hormone may need higher doses. Estrogens can cause fluid retention, low calcium in hypoparathyroidism, and worsen endometriosis, hereditary angioedema, asthma, diabetes, epilepsy, migraine, porphyria, lupus and liver hemangiomas (sections 5.11 to 5.16).
From the Patient Information that comes with Menostar:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.