Hops are sedating and are used for anxiety and insomnia. They can cause excess drowsiness, so people who are driving or who otherwise need to stay alert should use it with caution. Hops should not be used by people with depression.
Hops can affect the metabolism of prescription drugs in the liver, such as drugs for allergies, fungal infections, cancer, high cholesterol or oral contraceptives.
The plant contains compounds called miroestrol and deoxymiroestrol, which have been found to have estrogen-like effects in the body.
Like the other herbs used for natural breast enhancement, pueraria mirifica should not be used by pregnant or nursing women, people with hormone-sensitive cancers, or by people using oral contraceptives as contraception.
In one study examining pueraria mirifica in perimenopausal women, side effects included anemia.
We don't know why saw palmetto would work as a bust-enhancer. There is no scientific evidence linking DHT or testosterone levels from saw palmetto with breast enlargement.
Saw palmetto should not be used by pregnant or nursing women or people with hormone dependent cancers.
Saw palmetto has been found slow blood clotting, so it should not be used before or after surgery, but people with bleeding disorders, and by people taking "blood-thinnig"medications, such as Coumadin (warfarin), Plavix (clopidogrel), Ticlid (ticlopidine), Trental (pentoxifylline), heparin, and aspirin. Saw palmetto may decrease the effectiveness of oral contraceptives.
More on Saw Palmetto.
We don't know how wild yam could increase breast size. Diosgenin can be converted to estrogen and progesterone, but it must be done in a lab because the human body can't convert it on its own.
One recent study did find that wild yam consumption altered estrogen levels. In the study, 24 postmenopausal women replaced their staple food with 390 g of yam in 2 of 3 meals per day for 30 days. After yam ingestion, there were significant increases in concentrations of estrone (26%), sex hormone binding globulin (SHBG) (9.5%), and a near significant increase in estradiol (27%).
Wild yam should not be used by pregnant or nursing women, by women using oral contraceptives as contraception, or by people with hormone sensitive cancers.
If this is true, there are potential risks. Prolactin is a hormone that rises almost ten-fold during pregnancy to stimulate breast development and milk formation. High levels of prolactin can cause infertility, irregular menstruation, reduced libido, and possibly increase the risk of stroke.
Growth hormone is needed to stimulate growth in children. High levels of growth hormone in adults who don't need it can cause the development of diabetes, abnormal growth of bones and internal organs such as the heart, kidneys, and liver, high blood pressure, and atherosclerosis (hardening of the arteries).
Bottom LineAlthough it may seem like there is no harm in trying natural breast enlargement pills for one or two months to see if they'll work, we know far too little about the side effects and safety of these "miracle" pills.
Albert-Puleo M. "Fennel and anise as estrogenic agents". Journal of Ethnopharmacology. 2.4 (1980):337-44.
Circosta C et al. "Estrogenic activity of standardized extract of Angelica sinensis". Phytotherapy Research. 2006 May 12.
Fugh-Berman A. "Bust enhancing herbal products". Obstetrics and Gynecology. 101.6 (2003): 1345-9.
Goh SY and Loh KC. "Gynaecomastia and the herbal tonic Dong Quai". Singapore Medical Journal. 42.3 (2001):115-6.
Kassem A et al. "Evaluation of the potential antifertility effect of fenugreek seeds in male and female rabbits". Contraception. 73.3 (2006):301-6.
Lamlertkittikul S and Chandeying V. "Efficacy and safety of Pueraria mirifica (Kwao Kruea Khao) for the treatment of vasomotor symptoms in perimenopausal women: Phase II Study". Journal of The Medical Association of Thailand. 87.1 (2004):33-40.
Liu J et al. "Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms" . Journal of Agricultural and Food Chemistry. 49.5 (2001):2472-9.
Liu Z et al. "Correlation comparison of uterotrophic assay and E-SCREEN assay for estrogenic activities." Wei Sheng Yan Jiu. 33.4 (2004):458-60.
Trisomboon H et al. "The estrogenic effect of Pueraria mirifica on gonadotrophin levels in aged monkeys". Endocrine. 29.1 (2006):129-34.
Wu WH et al. "Estrogenic effect of yam ingestion in healthy postmenopausal women". Journal of the American College of Nutrition. 24.4 (2005):235-43.
Zava DT, Dollbaum CM, Blen M. Estrogen and progestin bioactivity of foods, herbs, and spices. Proc Soc ExpBiol Med. 217 (1998): 369–378.