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.
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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
How to take it
Interactions
With medications
- tamoxifen and aromatase inhibitors
An ER-beta-preferring phytoestrogen may interfere with anti-estrogen treatment. do not combine without oncology advice
- hormone replacement therapy
Adds a further estrogenic signal on top of prescribed hormones with no data on the combination. talk to your doctor before combining
With other supplements
- other phytoestrogens (soy isoflavones, red clover)
Additive estrogenic activity that has not been studied together. use one at a time
Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.
Frequently asked questions
Does Siberian rhubarb work for hot flashes?
The evidence is moderate: placebo-controlled trials of the Siberian rhubarb extract ERr 731 found reduced hot flushes and menopausal symptom scores, with a meta-analysis of 4 trials showing a drop of about 15 points on the Menopause Rating Scale. All the trials used one proprietary extract and are manufacturer-linked.
What dose of Siberian rhubarb (ERr 731) should you take?
Take one enteric-coated tablet containing 4 mg of ERr 731 per day, the dose used in every trial, and swallow it whole. Allow four to twelve weeks before judging whether Siberian rhubarb has helped.
Is generic Siberian rhubarb powder the same as ERr 731?
No. Generic "Siberian rhubarb" products are a different preparation with none of the trial evidence, so check that the label says ERr 731 specifically.
Is Siberian rhubarb safe long term?
Siberian rhubarb extract ERr 731 was well tolerated in trials of up to two years with no endometrial changes reported, but those studies were small and manufacturer-linked, so long-term safety is not settled. Avoid it with hormone-sensitive cancers or in pregnancy, and talk to your doctor if you take hormone therapy or tamoxifen.
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
- Efficacy evaluation of standardized Rheum rhaponticum root extract (ERr 731 (®)) on symptoms of menopause: A systematic review and meta-analysis study
- Long-term efficacy and safety of the special extract ERr 731 of Rheum rhaponticum in perimenopausal women with menopausal symptoms
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