Moderate evidenceWomen's health

Siberian Rhubarb (ERr 731)

A standardised rhapontic rhubarb root extract with several placebo-controlled trials showing reduced hot flushes and menopausal symptom scores. The caveat is that all of the evidence concerns one proprietary extract and comes from investigators linked to its manufacturer.

Evidence last reviewed: August 2026

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What the science says

Reduces menopausal symptoms versus placebo Moderate evidence
A 12-week multicentre randomized double-blind placebo-controlled trial in 109 perimenopausal women found ERr 731 lowered the Menopause Rating Scale II total score and every individual symptom versus placebo (p<0.0001), with hot flush number and severity falling from week 4.
Pooled effect across trials Moderate evidence
A meta-analysis of 4 trials (390 participants) found ERr 731 reduced Menopause Rating Scale scores by about 15 points versus control. The authors flagged potential bias and high heterogeneity, and every included trial used the same proprietary extract.
Longer-term use Limited evidence
A 96-week follow-up of the original trial participants reported continued symptom reduction and no clinically relevant change in safety parameters, but it was an open observational extension without a control group.

Dosage & safety

Studied doseOne enteric-coated tablet containing 4 mg of the standardised ERr 731 extract per day — the dose used in every trial. Generic "Siberian rhubarb" products are not the same preparation.

SafetyWell tolerated in trials lasting up to two years, with no endometrial changes reported; those studies were manufacturer-linked and modest in size, so long-term safety is not settled. Rhaponticin acts as a weak ER-beta-preferring phytoestrogen — avoid with hormone-sensitive cancers, in pregnancy and while breastfeeding, and discuss with your doctor if you take hormone therapy or tamoxifen. Not the same plant as culinary or laxative rhubarb species.

Scientific references

Efficacy and safety of a special extract of Rheum rhaponticum (ERr 731) in perimenopausal women with climacteric complaints: a 12-week randomized, double-blind, placebo-controlled trial
Heger M, Ventskovskiy BM, Borzenko I — Menopause, 2006
Efficacy evaluation of standardized Rheum rhaponticum root extract (ERr 731 (®)) on symptoms of menopause: A systematic review and meta-analysis study
Dubey VP, Sureja VP, Kheni DB — J Biomed Res, 2024
Long-term efficacy and safety of the special extract ERr 731 of Rheum rhaponticum in perimenopausal women with menopausal symptoms
Hasper I, Ventskovskiy BM, Rettenberger R — Menopause, 2009

Where to buy

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