The Fennel Herb and Estrogen
Fennel is a flavorful plant used extensively in herbal medicine and in cooking. The plant's fibrous bulb is eaten as a vegetable, while its seeds are used as seasonings and supplements. Fennel owes its licorice-like flavor to natural plant compounds which are similar to the hormone estrogen. Fennel's exact effects on the human body are poorly understood, but it may raise levels of estrogen if it is consumed in large amounts.
Fennel contains a complex of estrogen-affecting compounds. An evaluation published in the "Journal of Enthnopharmacology" found that fennel's primary estrogen-like compounds include anethole, photoanethole and dianethole, which it shares with similar-tasting plants, such as licorice root, anise and star-anise. When used in small quantities as flavoring agents, these compounds are generally recognized as safe, by the Food and Drug Administration.
Is Vitex Safe in Pregnancy?
Estrogen-like plant compounds, such as those found in fennel, have a notable effect on human hormones. The "Journal of Ethnopharmacology" notes that fennel has a long history of use as a treatment for lactation problems, infertility and pregnancy complications. The "Journal of Integrative Cancer Therapies" notes that these plant compounds may impact hormone levels in women with estrogen-sensitive conditions such as breast cancer and ovarian cancer. However, scientists are not yet certain whether these hormonal effects are beneficial or detrimental to women with these disorders.
- Estrogen-like plant compounds, such as those found in fennel, have a notable effect on human hormones.
- The "Journal of Integrative Cancer Therapies" notes that these plant compounds may impact hormone levels in women with estrogen-sensitive conditions such as breast cancer and ovarian cancer.
Herbal supplement manufacturers frequently advertise fennel, without FDA approval, as a natural breast enhancer. MayoClinic.com physician Sandhya Pruthi strongly urges against the use of these products, noting that there is insufficient evidence of their safety or efficacy. It is, however, plausible that fennel's estrogen-altering can increase breast size. Renowned lactation expert Kelly Bonyata recommends the herb to nursing women as a galactagogue, or breast milk enhancer. When given fennel tea as a colic remedy, many babies have experienced thelarche, or premature breast development, according to the "Journal of Pediatric Surgery." These findings suggest that medicinal amounts of fennel affect breast tissue.
- Herbal supplement manufacturers frequently advertise fennel, without FDA approval, as a natural breast enhancer.
- When given fennel tea as a colic remedy, many babies have experienced thelarche, or premature breast development, according to the "Journal of Pediatric Surgery."
Korean Ginseng & Pregnancy
Fennel used as a food does not generally cause side effects or notable changes in hormone levels. However, medicinal quantities may pose a danger. In addition to causing alarming development of secondary sex characteristics in children, large quantities of fennel can also increase the risk of some forms of cancer. Fennel's hormonal effects could also influence fertility, pregnancy and hormone-sensitive cancers. Until scientists understand more about fennel's pharmacological effects, do not use fennel as a medicinal food without consulting your doctor.
- Fennel used as a food does not generally cause side effects or notable changes in hormone levels.
Is Vitex Safe in Pregnancy?
Korean Ginseng & Pregnancy
Is it Possible to Take Vitex With Birth Control?
Side Effects of Herbal MenoSense
Fenugreek Seeds & Low Estrogen
My Fennel Allergy
Sarsaparilla Root Side Effects
Herbs to Decrease Testosterone
Will Drinking Green Tea Lower Androgen in Women?
The Side Effects of Agnus Castus
- "Journal of Ethnopharmacology"; Fennel and Anise as Estrogenic Agents; M.Albert-Puleo; December 1980
- "Food and Chemical Toxicology"; The FEMA GRAS Assessment of trans-Anethole Used as a Flavouring Substance; P. Newberne et al.; July 1999
- "Integrative Cancer Therapy"; Phytoestrogens in Botanical Supplements -- Implications for Cancer; C.E. Piersen; June 2003
- "Journal of Pediatric Surgery"; A Striking and Frequent Cause of Premature Thelarche in Children -- Foeniculum Vulgare; Z. Turkyilmaz et al.; November 2008
- Kellymom.com; Fennel; Kelly Bonyata
- MayoClinic.com: Natural Breast Enhancement -- Is it Safe?
- U.S. Department of Agriculture. FoodData Central. Fennel, bulb, raw. 2019.
- Badgujar SB, Patel VV, Bandivdekar AH. Foeniculum vulgare Mill: A Review of Its Botany, Phytochemistry, Pharmacology, Contemporary Application, and Toxicology. Biomed Res Int. 2014;2014:842674. doi:10.1155/2014/842674
- Shahat AA, Ibrahim AY, Hendawy SF, et al. Chemical Composition, Antimicrobial and Antioxidant Activities of Essential Oils from Organically Cultivated Fennel Cultivars. Molecules. 2011;16(2):1366-1377. doi:10.3390/molecules16021366
- Swathi V, Rekha R, Abhishek J, Radha G, Pallavi SK, Praveen G. Effect of Chewing Fennel and Cardamom Seeds on Dental Plaque and Salivary pH – A Randomized Controlled Trial. Int J Pharm Sci Res. 2016;7(1):406-412. doi:10.13040/IJPSR.0975-8232.7
- National Institutes of Health. Office of Dietary Supplements. Vitamin C Fact Sheet for Health Professionals. Updated February 27, 2020.
- Di Ciaula A, Portincasa P, Maes N, Albert A. Efficacy of bio-optimized extracts of turmeric and essential fennel oil on the quality of life in patients with irritable bowel syndrome. Ann Gastroenterol. 2018;31(6):685-691. doi:10.20524/aog.2018.0304
- American Academy of Allergy Asthma and Immunology. Can spices cause allergic reactions? 2020.
- Allergy & ENT Specialists of Central Florida. Fennel. Updated 2015.
- Berkeley Wellness. University of California. Fennel: The Flavor of Sweet Anise. 2016.
- Centers for Disease Control and Prevention. Fruit and Vegetable Safety. Updated February 12, 2020.
Juniper Russo, an eclectic autodidact, has been writing professionally since 2008. Her work has appeared in several online and print-based publications, including Animal Wellness. Russo regularly publishes health-related content and advocates an evidence-based, naturopathic approach to health care.