Rhapontic rhubarb (Rheum rhaponticum), specifically its root extract (often called ERr 731), is used to support the estrogen body system, particularly in the management of menopausal symptoms. This use is supported by several clinical studies. The root extract contains rhaponticin and other stilbenes that act as selective estrogen receptor modulators (SERMs), primarily binding to estrogen receptor beta (ERβ). This activity is thought to alleviate menopausal symptoms (such as hot flashes and sweating) without stimulating estrogen receptor alpha (ERα), which is more associated with the risk of breast and endometrial stimulation.

Randomized, double-blind, placebo-controlled trials have shown that ERr 731 significantly reduces the frequency and severity of menopausal symptoms compared to placebo, with a favorable safety profile over periods of up to 12 months. Furthermore, preclinical studies support the SERM-like activity and the lack of proliferative effects on breast and endometrial tissue. The German Commission E and other European health authorities have recognized rhapontic rhubarb root extract as a safe and effective option for menopausal complaints.

While the overall body of evidence is moderate (hence the rating of 3), and more long-term studies would be beneficial, the current scientific literature supports the use of Rhapontic rhubarb root extract for estrogen-related body system support, especially in the context of menopausal symptom relief.