Red Clover Trifolium Pratense Blossom Extract
Also known as: Red clover, Purple clover, Red clover blossom extract, Trifolium pratense
Overview
Red clover blossom extract, derived from the flowers of *Trifolium pratense*, is a herbal supplement rich in isoflavones, notably biochanin A and formononetin. These compounds are phytoestrogens, meaning they are plant-derived substances structurally similar to human estrogen. The extract is primarily utilized for its potential to alleviate menopausal symptoms, particularly hot flushes, due to its estrogenic activity. While research on red clover is ongoing, several randomized controlled trials and meta-analyses support its use, though the quality and consistency of evidence can vary. It is considered a botanical supplement with a moderate level of research maturity, offering a natural alternative for managing certain menopausal discomforts. The active constituents, isoflavones, are metabolized in the body to compounds like genistein and daidzein, which contribute to its therapeutic effects.
Benefits
The primary evidence-based benefit of red clover extract is the reduction in the frequency of hot flushes in perimenopausal and postmenopausal women. A meta-analysis of eight randomized controlled trials (RCTs) demonstrated a statistically significant reduction of approximately 1.7 fewer hot flushes per day compared to placebo after 12 weeks, particularly with doses of 80 mg/day or more of isoflavones, especially those high in biochanin A. This effect is most pronounced in women experiencing at least five hot flushes daily. While some studies suggest moderate improvements in overall menopausal symptoms, these effects are often less consistent or statistically significant than the reduction in hot flushes. The clinical meaningfulness of these benefits can vary individually, but the evidence for hot flush reduction is considered modest yet statistically robust.
How it works
Red clover isoflavones function as selective estrogen receptor modulators (SERMs). They bind to estrogen receptors (ERα and ERβ), showing a preferential affinity for ERβ. This interaction allows them to mimic or modulate the effects of endogenous estrogen, particularly in states of estrogen deficiency, such as during menopause. The key isoflavones, biochanin A and formononetin, are metabolized in the gut into active compounds like genistein and daidzein, which are responsible for the observed estrogenic effects. The absorption and bioavailability of these compounds are influenced by the specific formulation of the extract and the individual's gut microbiota.
Side effects
Red clover extract is generally considered safe for short-term use in menopausal women, with a low incidence of adverse effects. Mild gastrointestinal discomfort and skin reactions are rare but possible common side effects (occurring in >5% of users). Uncommon side effects (1-5%) may include breast tenderness and minor allergic reactions. Rare side effects (<1%) are not well documented but could potentially involve estrogenic-related effects. Important drug interactions exist: red clover may interfere with estrogen therapies and could potentially reduce the efficacy of tamoxifen. It may also increase the toxicity of methotrexate and interact with drugs metabolized by liver enzymes CYP1A2 and CYP2C19. Red clover is contraindicated in women with hormone-sensitive cancers or those currently taking tamoxifen. Caution is advised for individuals with any estrogen-sensitive conditions.
Dosage
The minimum effective dose for red clover isoflavones is approximately 80 mg per day. The optimal dosage range is typically between 80 and 120 mg per day of isoflavones, ideally standardized to their biochanin A content. While a maximum safe dose has not been firmly established, doses up to 120 mg/day have been used in clinical trials and appear safe for up to 12 weeks. Red clover extract should be taken orally on a daily basis, as benefits are typically observed after about 12 weeks of consistent use. It is recommended to use standardized extracts with a quantified isoflavone content to ensure consistent dosing. Absorption may be enhanced when taken with food, and individual metabolism can influence bioavailability.
FAQs
Is red clover safe for breast cancer survivors?
Due to its estrogenic activity, the evidence regarding red clover's safety for breast cancer survivors is inconclusive. It is crucial to consult with a healthcare provider before use, especially if you have a history of hormone-sensitive cancers.
How soon will I see results from red clover?
Benefits from red clover, particularly for hot flushes, typically become noticeable after approximately 12 weeks of consistent daily supplementation.
Can red clover replace hormone replacement therapy (HRT)?
Red clover may modestly reduce hot flushes, but it is not a substitute for hormone replacement therapy (HRT), especially in cases of severe menopausal symptoms or for other benefits provided by HRT.
Are there interactions with medications?
Yes, red clover can interact with certain medications, including tamoxifen, methotrexate, and estrogen therapies. It may also affect drugs metabolized by specific liver enzymes. Always discuss with your doctor.
Does red clover cause side effects?
Side effects are generally mild and uncommon, primarily involving mild gastrointestinal discomfort or skin reactions. Serious side effects are rare, but caution is advised due to its estrogenic properties.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/33920485/ – This meta-analysis of eight randomized controlled trials found a statistically significant reduction in hot flush frequency (WMD -1.73/day) with red clover isoflavone doses of 80 mg/day or more over 12 weeks in perimenopausal and postmenopausal women. The study highlights the modest but significant efficacy of red clover for this specific menopausal symptom.
- https://www.drugs.com/npp/red-clover.html – This source, citing Cochrane reviews and other systematic analyses, indicates mixed results for red clover's efficacy on hot flushes and overall menopausal symptoms. While some studies show positive effects, others report non-significant findings, suggesting variability in study design, sample size, and formulation.
- https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0081968 – This systematic review on breast cancer risk and red clover found no clear adverse effects on breast tissue in the included randomized controlled trials. It suggests a low to moderate risk of bias in the studies reviewed, but notes heterogeneity in interventions and outcomes, and a limited number of red clover-specific studies.
- https://www.webmd.com/vitamins/ai/ingredientmono-308/red-clover – This source provides a general overview of red clover, including its uses, potential side effects, and interactions. It serves as a comprehensive resource for common questions and safety considerations related to red clover supplementation.