The therapeutic effectiveness of wild yam has not been significantly investigated under clinical trial conditions, so evidence is derived from traditional, in vitro and animal studies.
MENOPAUSAL SYMPTOMS AND OTHER FEMALE REPRODUCTIVE CONDITIONS
Although wild yam is a popular treatment for menopausal symptoms, there is currently no clinical research supporting its use for these indications.
Wild yam has been used as a ‘natural alternative’ to oestrogen replacement therapy, to treat postmenopausal vaginal dryness, PMS, osteoporosis, and to increase energy and libido in men and women, as well as for breast enlargement. The use of wild yam as a natural progesterone appears misguided because diosgenin is not converted to progesterone, DHEA or other steroid hormones in vivo. One small, double-blind, placebo-controlled crossover trial of topical wild yam extract showed no effect on menopausal symptoms. The study involved 23 healthy women suffering from troublesome symptoms of the menopause. After a 4-week baseline period, each woman was randomly assigned the active cream and matching placebo for 3 months. No changes in body weight, SBP or DBP, levels of total serum cholesterol, triglyceride, HDL-cholesterol, FSH, glucose, oestradiol, or serum or salivary progesterone were detected after 3 months’ treatment.
Wild yam has been used traditionally as an antispasmodic for treating diverticulosis, gall bladder colic, painful menstruation, cramp, nausea in pregnancy, rheumatoid arthritis, and for increasing energy, and may be useful when combined with other herbs for irritable bowel syndrome.
• Decoction of dried root: 2-4 g three times daily.
• Tincture (1:5): 2-10 mL three times daily.
• Liquid extract (1:2): 3-6 mL/day.
Considering that wild yams are widely consumed as food by several tribal groups, it appears that dietary ingestion is non-toxic. After assessment with short-term toxicity tests, dermal irritation tests, a sensitisation test, an ocular irritation test, a rat uterotropic assay, and genotoxicity tests wild yam was deemed safe for use in cosmetic products.
In large doses, wild yam may cause nausea, vomiting and diarrhoea.