Dioscoreaceae
Dioscorea villosa
Wild yam · Colic root
- Part used
- rhizomeroot
- Native range
- Eastern North America
- Morphology
- A slender twining vine with heart-shaped leaves marked by deep parallel veins, and small greenish flowers, over a knotted woody rhizome.
What is in it
Evidence
No supported use. Trials of wild yam cream for menopausal symptoms found no effect and no change in hormone levels. Where such creams have appeared to work, analysis has repeatedly found undeclared synthetic progesterone added.
Safety
The plant itself is low-risk. The hazard is the product: creams sold as natural progesterone have been found to contain actual pharmaceutical progesterone, unlabelled, which is a real hormonal drug being taken by people who believe they are using a plant extract.
Interactions: Where products are adulterated, all the interactions of progesterone apply
Regulatory: Permitted as a listed ingredient. Undeclared hormone content is illegal and has been found repeatedly.
Historical use
Used by eastern North American peoples and by the Eclectics for colic and cramp — the common name colic root records it. Marketed since the 1990s as a natural source of progesterone, which it is not.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
What it is taken for, and who says so
Sold as a cream or capsule for menopausal symptoms and menstrual cramps, frequently marketed as a natural source of progesterone — which the body cannot make from it.
Recorded because it is what people believe, not because it is what the plant does. Whether any of it holds up is the Evidence section above, and the two frequently disagree. A sincere account of feeling better is compatible with the plant doing nothing — see the placebo effect.
Worth knowing
Wild yam is the most instructive false claim in this collection, because the truth behind it is genuinely remarkable and the claim still does not follow.
Diosgenin, from Dioscorea species, was the starting material for the industrial synthesis of steroid hormones. Russell Marker worked out in the 1940s how to convert it to progesterone, went to Mexico, and founded the company that became Syntex — which made the oral contraceptive pill economically possible. Mexican yams underwrote the sexual revolution.
But that conversion is a multi-step chemical synthesis carried out in a factory. The human body cannot do it. Diosgenin taken orally or applied as a cream does not become progesterone; it is simply diosgenin. "Natural progesterone from wild yam" is a claim with a true and famous history attached to a false biology — and the products that appear to work have generally been found to contain the real hormone, added.
Nomenclature verified against GBIF backbone taxonomy.