Wild Yam
Summary
Wild yam is sold as creams and capsules for menopause, often described as natural progesterone. In the only placebo-controlled trial, a wild yam cream did not ease menopausal symptoms or change hormone levels (grade D). Evidence for oral wild yam is essentially absent; one small trial of a related Chinese yam extract reported better cognitive scores.
Key facts
- The root of Dioscorea villosa; extracts contain steroidal saponins and up to 3.5% diosgenin[1]
- Menopausal symptoms: no difference from placebo for a wild yam cream (D)[2]
- Three months of wild yam cream did not change serum or salivary progesterone, estradiol or FSH[2]
- A diosgenin-rich Chinese yam (Dioscorea batatas) extract raised total cognitive test scores in 28 adults (D)[3]
- Cosmetic safety panels judged the root extract safe in skin products; a rat study linked oral extract to kidney fibrosis[1][6][5]
- 2 graded human outcomes on this page
- October 10, 2026
How it works
ProposedDiosgenin is a plant steroid that the pharmaceutical industry converts to steroid hormones in the lab. Claims that it raises the body's own hormones are not supported: a wild yam cream did not change progesterone or estradiol levels in a trial.[1][2]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Cognition | Grade D | Improved | Crossover RCT · n = 28 · 2017 | 1 row |
| Menopause | Grade D | No effect | Crossover RCT · n = 23 · 2001 | 1 row |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Cognitive function (related species) | Improved | Grade D | Crossover RCT · n = 28 · 2017 Healthy Japanese adults aged 20–81 Form: Diosgenin-rich Chinese yam (Dioscorea batatas) extract in olive oil capsules · Dose: 50 mg/day of extract (8 mg diosgenin) · Duration: 12 weeks per arm, 6-week washout Total RBANS cognitive score rose versus placebo; of 12 subtests, only semantic fluency improved significantly. No adverse effects on blood tests. | 29064406 (opens PubMed)Source [3] |
| Menopausal symptoms, lipids and sex hormones | No effect | Grade D | Crossover RCT · n = 23 · 2001 Healthy women with troublesome menopausal symptoms (average age 53) Form: Topical wild yam cream · Dose: Applied daily (amount not stated in the abstract) · Duration: 3 months per arm No difference from placebo cream in hot flushes, night sweats or other symptoms; no change in weight, blood pressure, lipids, glucose, FSH, estradiol, or serum or salivary progesterone. No significant side effects. | 11428178 (opens PubMed)Source [2] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Topical wild yam cream | Varies[2] | Salivary and serum progesterone did not change after 3 months of use, so there is no sign of hormonal activity.[2] | No significant side effects over 3 months.[2] | Menopausal symptoms (one placebo-controlled trial) |
| Oral wild yam root extract (capsules or tincture) | Varies[1][5] | No human absorption data in our sources.[1] | No human trial data; in rats, oral extract caused kidney fibrosis and liver inflammation by 28 days.[5] | Not studied in published human trials found for this page |
| Diosgenin-rich Chinese yam (Dioscorea batatas) extract | Varies[3] | No human absorption data in our sources; the extract was given in olive oil to aid uptake.[3] | No adverse effects on blood tests over 12 weeks.[3] | Cognitive scores in healthy adults (50 mg/day) |
Studied doses
Doses studied in human trials ranged from a daily topical wild yam cream for 3 months (amount not given in the abstract) to 50 mg/day of a related Chinese yam extract supplying 8 mg of diosgenin for 12 weeks. No placebo-controlled trial of oral wild yam was found.[2][3]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Kidney problems
- In rats, oral wild yam extract increased kidney fibrosis over 28 days; the authors advise caution in people with reduced kidney function or on drugs that affect the kidneys.[5]
- Pregnancy and breastfeeding
- No human safety data were found for oral wild yam in pregnancy or breastfeeding.[1][2]
- Expecting a hormone effect
- Wild yam cream did not change progesterone or estradiol, so it is not a substitute for prescribed progesterone.[2]
- Sensitive skin
- Undiluted root extract irritated rabbit skin, although a 10% dilution did not.[1]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Safety
Topical use looked safe in short studies; oral long-term safety is unknown.
- Topical use
- No significant side effects over 3 months in the menopause cream trial.[2]
- Cosmetic safety panels
- Cosmetic safety panels found the root extract safe in skin products at reported concentrations (2004, reaffirmed 2023).[1][6]
- Kidney and liver in animals
- Rats fed 0.79 g/kg/day of extract developed kidney fibrosis and liver inflammation by 28 days, without acute toxicity.[5]
- Acute toxicity in animals
- A high oral dose (2 g/kg) killed 1 of 10 rats; 0.5 g/kg caused no toxicity.[1]
How to read the label
- Label dose vs clinical doseThe one controlled wild yam trial used a cream for 3 months with no benefit; no oral dose has been tested against placebo. The related Chinese yam trial used 50 mg/day of extract (8 mg diosgenin).[2][3]
- "Natural progesterone" claimsDiosgenin is a raw material for lab steroid synthesis, and wild yam cream did not raise serum or salivary progesterone.[1][2]
- DHEA claimsIn older volunteers, three weeks of a yam steroid extract did not change blood DHEA-S levels.[4]
- Species mattersChinese yam (Dioscorea batatas) and wild yam (Dioscorea villosa) are different plants; results from one do not carry over to the other.[3][2]
Frequently asked questions
Does wild yam help menopause symptoms?
In a 3-month placebo-controlled crossover trial in 23 women, wild yam cream did no better than placebo for hot flushes or other symptoms.[2]
Does wild yam contain progesterone?
No. It contains diosgenin, which drug makers convert to steroids in the lab; wild yam cream did not raise progesterone levels in women.[1][2]
Does wild yam raise DHEA?
In older volunteers, three weeks of a yam steroid extract did not change blood DHEA-S levels.[4]
Is wild yam safe?
Topical cream caused no significant side effects over 3 months. Oral safety in people is unstudied, and a rat study linked the extract to kidney fibrosis.[2][5]
Does yam extract improve memory?
A 12-week trial of a Chinese yam extract, a different species, raised total cognitive scores in 28 healthy adults; wild yam itself has not been tested.[3]
Sources
- [1]Final report of the amended safety assessment of Dioscorea Villosa (Wild Yam) root extract.. Int J Toxicol, 2004. review
- [2]Effects of wild yam extract on menopausal symptoms, lipids and sex hormones in healthy menopausal women.. Climacteric, 2001. crossover-RCT
- [3]Diosgenin-Rich Yam Extract Enhances Cognitive Function: A Placebo-Controlled, Randomized, Double-Blind, Crossover Study of Healthy Adults.. Nutrients, 2017. crossover-RCT
- [4]Antioxidant activity of dioscorea and dehydroepiandrosterone (DHEA) in older humans.. Life Sci, 1996. open-label
- [5]Dioscorea villosa (wild yam) induces chronic kidney injury via pro-fibrotic pathways.. Food Chem Toxicol, 2008. animal-study
- [6]Dioscorea Villosa (Wild Yam) Root Extract.. Int J Toxicol, 2023. review
What changed
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year taken from the record) and abstracts read for the cited rows.
- Adversarial review pass: every evidence row re-read against its PubMed abstract; the cognition trial species (Dioscorea batatas) and dose (50 mg extract, 8 mg diosgenin) confirmed in the PMC full text (PMC5691776). Official sources: no ODS fact sheet, NCCIH page (NCCIH A–Z and herbs-at-a-glance checked; NCCIH points to a retired MedlinePlus monograph) or EMA monograph exists for wild yam. Industry ties: the 2023 Cosmetic Ingredient Review reaffirmation declares sponsorship by the Cosmetic Ingredient Review (an industry-funded panel); a co-author of the Chinese yam trial is affiliated with Resilio Company, which supported its patent application; funding for the 2001 cream trial is not stated in PubMed. Retraction, expression-of-concern, erratum and withdrawn checks on all 6 PMIDs: none flagged. Page set indexable. Independent browser review (4 parallel reviewers, every evidence row checked against its abstract and official sources on the Vercel preview) found: no factual errors; the cosmetic-panel safety statement now cites only the two panel reports (menopause trial cited separately).