What are the effects of excessive estrogen (E2) levels?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: March 12, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Excessive estrogen levels can lead to a range of health issues, including increased risk of breast and endometrial cancer, blood clots, stroke, and gallbladder disease, as well as worsening conditions like endometriosis and fibroids. The effects of excessive estrogen (E2) levels can be detrimental to both men and women, causing a variety of symptoms and increasing the risk of certain diseases.

Key Health Issues Associated with Excessive Estrogen Levels

  • Weight gain, particularly around the hips and thighs
  • Mood swings, headaches, and fatigue
  • Menstrual problems, including heavy bleeding, irregular periods, or worsened premenstrual syndrome symptoms in women
  • Gynecomastia (enlarged breast tissue), erectile dysfunction, and reduced fertility in men
  • Increased risk of certain cancers, particularly breast and endometrial cancer in women
  • Contribution to blood clots, stroke, and gallbladder disease
  • Worsening of conditions like endometriosis and fibroids

According to a study published in the Annals of Internal Medicine 1, hormone therapy, which involves the administration of estrogen and progestin, has been shown to increase the risk of stroke and coronary heart disease (CHD). Another study published in the same journal 1 found that hormone replacement therapy (HRT) increases the incidence of breast cancer, but its effects on breast cancer mortality are uncertain.

Importance of Consulting a Healthcare Provider

If high estrogen levels are suspected, it is essential to consult a healthcare provider who can order appropriate tests and recommend treatments ranging from lifestyle changes to medications that block estrogen production or effects. This is crucial in preventing and managing the potential health issues associated with excessive estrogen levels.

From the FDA Drug Label

The growth of many cancers of the breast is stimulated or maintained by estrogens. The effects of excessive estrogen (E2) levels are not directly stated in the drug label. Key points:

  • The label discusses the role of estrogens in stimulating or maintaining the growth of many breast cancers.
  • It does not provide information on the effects of excessive estrogen levels. 2

From the Research

Effects of Excessive Estrogen (E2) Levels

  • Excessive estrogen (E2) levels have been associated with an increased risk of breast cancer, as evident from studies that show a link between high E2 levels and breast cancer risk 3, 4.
  • The relationship between estrogen levels and breast cancer risk is complex and may be influenced by factors such as body mass index (BMI), menopausal status, and estrogen replacement therapy 5.
  • High levels of estrogen have also been linked to an increased risk of endometrial and ovarian cancer, although the evidence is not as strong as it is for breast cancer 4.
  • Estrogen-only hormone replacement therapy (HRT) has been shown to have little impact on breast cancer risk in naturally or surgically menopausal women, and may even have a beneficial effect in some cases 6.
  • Dietary patterns that are associated with high estrogen levels, such as a diet high in certain foods that influence hormone levels, may also increase the risk of breast cancer 7.

Cancer Risk

  • The risk of breast cancer associated with high estrogen levels is particularly significant for estrogen-receptor-positive tumors 4, 7.
  • Ovarian cancer risk has also been linked to high estrogen levels, with a significant increase in risk observed in studies 4.
  • The relationship between estrogen levels and endometrial cancer risk is less clear, with some studies suggesting a possible link but others finding no significant association 4.

Hormone Replacement Therapy

  • Estrogen-only HRT has been shown to have a range of benefits, including ameliorating menopausal symptoms and improving bone health 6.
  • However, the use of estrogen-plus-progestin HRT has been consistently associated with an increased risk of breast cancer, highlighting the importance of careful consideration of the risks and benefits of HRT 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Anastrozole has an Association between Degree of Estrogen Suppression and Outcomes in Early Breast Cancer and is a Ligand for Estrogen Receptor α.

Clinical cancer research : an official journal of the American Association for Cancer Research, 2020

Research

Estrogens and breast cancer.

Annals of oncology : official journal of the European Society for Medical Oncology, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.