Herbs and Hormone-Sensitive Conditions: Breast, Uterine and Prostate Cancers, Endometriosis
What the sources say about plant estrogens, black cohosh, red clover, hops and soy for people with breast, uterine or prostate cancer or endometriosis, and why to ask the care team first.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
Ask your cancer or gynecology team before using any herb. If you have, or have had, a hormone-sensitive cancer, or you take a hormone-blocking medicine, the herbs below are not simple "natural" extras. The European herbal monograph for black cohosh says people treated for breast cancer or other hormone-dependent tumours should not use it without medical advice. [1] Do not stop or change a prescribed medicine on your own; ask the prescriber or a pharmacist.
What "hormone-sensitive" and "phytoestrogen" mean here
A hormone-sensitive condition is one where the body's own hormones, mainly estrogen, can influence how the condition behaves. The sources we read describe breast and uterine cancers and endometriosis this way. [2] [3] Phytoestrogens are plant substances with either estrogen-like or estrogen-blocking activity, and their activity is weak compared with the body's own estrogens. [4] That mixed behavior is why they are discussed so carefully for people with these conditions.Why the question is hard to answer
One review of botanical supplements notes that phytoestrogens may serve as cancer-preventive agents and also may promote growth in estrogen receptor positive cancer cells in the laboratory. [4] It says this led to speculation that they might be ill advised for people at higher risk of hormone-dependent cancers. [4] That review was published in 2003 and covered red clover, black cohosh, hops, dong quai and licorice. [4] Cell and animal results do not tell us what happens in a person, so the sections below keep the two apart.Herb by herb: what the sources we read say
| Herb (plant part) | What the source found | Evidence label |
|---|---|---|
| Black cohosh (Actaea racemosa L., root and rhizome) | NCCIH says it is uncertain whether black cohosh is safe for women who have had hormone-sensitive conditions such as breast or uterine cancer. [2] The National Cancer Institute summary says claims of estrogen-like action are refuted by up-to-date laboratory and clinical studies of commercial hydroalcoholic extracts. [5] It also says double-blind trials in breast cancer survivors did not show hot flash reductions beyond placebo. [5] | Mixed; safety in hormone-sensitive disease uncertain |
| Red clover (Trifolium pratense L.; plant part not stated in the NCCIH fact sheet) | Its isoflavones are structurally similar to estrogen. [6] NCCIH says research has not shown conclusive evidence of benefit for any health condition. [6] Safety in hormone-sensitive cancers is not described in the sources we read. | Insufficient evidence; safety in hormone-sensitive disease not described |
| Hops (Humulus lupulus L., flowers) | The EU herbal monograph says tests on genotoxicity, reproductive toxicity and carcinogenicity have not been performed. [7] It also says safety in pregnancy and breastfeeding has not been established. [7] | Traditional use only (EU); safety data limited |
| Soy foods and soy isoflavone supplements (Glycine max (L.) Merr.) | NCCIH says observational studies link higher dietary soy intake with lower breast cancer risk in Asian and Asian-American women, and that soy supplements have not been shown to reduce breast cancer risk. [8] A meta-analysis of observational studies found soy and isoflavone intake before and after diagnosis was associated with reduced recurrence risk. [9] | Promising but limited for food intake; observational only |
Food and supplement are different things: the soy findings above concern dietary intake in the studies, not concentrated supplements. [8] [9] Plant names were checked in the GBIF database. [10]
Breast cancer and endocrine (hormone-blocking) therapy
The National Cancer Institute summary notes that black cohosh may mildly inhibit an enzyme (CYP2D6) that processes tamoxifen, and says even mild inhibition "may warrant consideration." [5] It also reports that observational studies did not find black cohosh linked to breast cancer development, and that one retrospective cohort reported lower recurrence in users of an extract product. [5] These are observational results and do not prove safety. Separately from cancer, the EU monograph says liver toxicity is associated with products containing black cohosh and advises stopping and seeing a doctor for signs such as yellow skin or eyes or dark urine. [1] See Black Cohosh and Herbs and Cancer Treatment.The EU monograph also says black cohosh should not be used together with estrogens unless a doctor advises it. [1]
Uterine (endometrial) conditions
The Cochrane review of plant-estrogen supplements for hot flashes reported no evidence of estrogen-like stimulation of the womb lining in trials of up to two years. [11] That review excluded women with a history of breast cancer, and it found no conclusive evidence that the supplements reduce hot flashes. [11] For people with uterine cancer, Proper evidence not found: we searched PubMed for herbal safety in hormone-sensitive and endometrial conditions and did not find a source we could read that answers the question.Prostate conditions
A 2025 review of natural products in prostate cancer says their role remains controversial because of inconsistent and limited success in clinical trials. [12] We did not find a source we could read that tests a single herb for people on prostate cancer hormone therapy, so no herb is described as safe or unsafe here. For symptom herbs see Saw Palmetto and Herbs for Prostate and Urinary Symptoms.Endometriosis
Endometriosis is described in a 2025 review as marked by persistent inflammation and estrogen dependence. [3] The reviews we read on herbs for it summarize laboratory mechanisms and call for further pre-clinical and clinical studies. [3] Proper evidence not found for a herb with trial-proven benefit or proven safety in endometriosis in the sources we read. For the condition itself see Endometriosis and Fibroids.Frequently asked questions
Is it safe to use black cohosh after breast cancer?
It is uncertain. NCCIH says it is uncertain whether black cohosh is safe for women who have had hormone-sensitive conditions such as breast or uterine cancer. [2] The EU monograph says to use it only with medical advice. [1] Ask your oncology team.
Do plant estrogens act like the body's estrogen?
They can act weakly, and some act as blockers, depending on the plant and the cell studied. [4] Laboratory results do not predict results in people. [4]
Is soy food a problem after hormone-sensitive breast cancer?
Observational studies linked soy food intake with lower recurrence risk, but these studies cannot prove cause. [9] NCCIH says soy supplements have not been shown to reduce breast cancer risk. [8] Ask your care team about supplements specifically.
Can herbs change how tamoxifen works?
The National Cancer Institute summary says black cohosh may mildly inhibit the enzyme that processes tamoxifen, though the clinical importance is unclear. [5] Ask a pharmacist about any herb you use with hormone-blocking medicine.
Is there a herb proven to treat endometriosis?
Proper evidence not found in the sources we read; the reviews describe laboratory mechanisms and call for more clinical studies. [3]
Related: Herbs for Menopause Symptoms, Black Cohosh, Soy, Red Clover and Hormone Balance Claims, Red Clover, Hops.
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Who should ask first, and what to bring
- Anyone being treated for or recovering from breast, uterine, ovarian or prostate cancer, or taking hormone-blocking medicine. Ask the oncology team and a pharmacist; see How Interactions Work.
- Anyone with liver disease, and anyone planning surgery; tell the surgical team about every herb. See Herbs Before and After Surgery.
- Anyone pregnant or breastfeeding: NCCIH says red clover supplements may be unsafe, and black cohosh may not be safe. [6] [2]
- Everyone: product contents can differ from the label. NCCIH notes some black cohosh products contained the wrong herb. [2] See Quality Testing and Certifications.
References
- European Medicines Agency, HMPC. European Union herbal monograph on Cimicifuga racemosa (L.) Nutt., rhizoma (EMA/HMPC/48745/2017, final, 2018). Available at www.ema.europa.eu. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NCCIH). Black Cohosh: Usefulness and Safety. Last updated November 2024. Read 2026-10-23.
- Elbanna AH, et al. Natural bioactive compounds and herbal medicines targeting common signaling pathways in endometriosis. Naunyn Schmiedebergs Arch Pharmacol. 2026;399(5):6249-6288 (online 2025). Read 2026-10-23.
- Piersen CE. Phytoestrogens in botanical dietary supplements: implications for cancer. Integr Cancer Ther. 2003;2(2):120-138. Read 2026-10-23.
- National Cancer Institute. Black Cohosh (PDQ), Health Professional Version. Read 2026-10-23.
- NCCIH. Red Clover: Usefulness and Safety. Last updated April 2025. Read 2026-10-23.
- European Medicines Agency, HMPC. Community herbal monograph on Humulus lupulus L., flos (EMA/HMPC/682384/2013, final, 2014). Available at www.ema.europa.eu. Read 2026-10-23.
- NCCIH. Soy: Usefulness and Safety. Last updated April 2025. Read 2026-10-23.
- Qiu S, Jiang C. Soy and isoflavones consumption and breast cancer survival and recurrence: a systematic review and meta-analysis. Eur J Nutr. 2019;58(8):3079-3090. Read 2026-10-23.
- GBIF Secretariat. GBIF Backbone Taxonomy species match for Actaea racemosa L., Trifolium pratense L., Humulus lupulus L., Echinacea purpurea (L.) Moench, Hypericum perforatum L., Ginkgo biloba L., Glycine max (L.) Merr., Ephedra sinica Stapf and Panax ginseng C.A.Mey. (all returned as accepted names). Read 2026-10-23.
- Lethaby A, et al. Phytoestrogens for menopausal vasomotor symptoms. Cochrane Database Syst Rev. 2013;(12):CD001395. Read 2026-10-23.
- Harnessing nature's therapeutic potential: a review of natural products in prostate cancer management. Urol Oncol. 2025. Read 2026-10-23.