Red clover (Trifolium pratense)

Herbal source of isoflavones (food supplement under Spanish RD 1487/2009)

ATC code: G03CX-RED-CLOVER (Red clover (Trifolium pratense), isoflavones)

Brand names – supplements

Estroven Red Clover, Promensil

Supplements are not tested in clinical trials and are not registered as medications.

Mechanism of action

Contains four main isoflavones: biochanin A, formononetin, genistein and daidzein. In the gut formononetin and biochanin A are converted into daidzein and genistein, which weakly bind estrogen receptors (β-form) – about 100-1000 times weaker than estradiol. The standardised Promensil extract delivers 40 mg of isoflavones per tablet. did not validate isoflavone health claims for menopause in its 2015 assessment.

Indications

Hot flashes and night sweats

Individual decision

Red clover isoflavones are used as a herbal option for moderate hot flashes. Cochrane Lethaby 2013 pooled phytoestrogen data and concluded that the reduction in flash frequency does not, on average, differ from placebo in a clinically meaningful way. Some RCTs with Promensil showed a small advantage, but effect sizes remain small. NG23 does not recommend isoflavones as a first-line standard. SEGO 2024 lists them as options with debatable benefit. If hot flashes are moderate and the patient prefers a herbal option, discuss a 2-3 month trial with the gynaecologist and reassess.

Sources

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Breast cancer prevention via supplements

Not recommended

Manufacturers promote red clover isoflavones as phytoestrogens for breast cancer prevention. There is no supporting evidence: none of the major systematic reviews (, , ) confirmed reduction in cancer risk. In patients with hormone-receptor-positive (HR+) breast cancer or a history of such cancer, use remains controversial – EFSA 2015 noted that isoflavones may activate ER-dependent signalling and advised avoiding long-term use in this group. SEGO 2024 does not recommend isoflavones in patients with HR+ tumours. If a doctor suggested red clover for breast cancer protection or to continue after a treated HR+ cancer, consider seeking a second opinion from a breast oncologist.

Sources

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Safety

Contraindications

Hypersensitivity to Trifolium pratense
History of hormone-receptor-positive (HR+) breast, ovarian or endometrial cancer
Pregnancy and lactation
Warfarin or other anticoagulants without INR monitoring (isoflavones may theoretically enhance the effect)

Serious adverse effects

Bleeding when combined with anticoagulants
Estrogen-dependent stimulation of HR+ tumours (theoretical)
Severe allergic reactions

Common adverse effects

Nausea and gastrointestinal discomfort
Headache
Menstrual cycle changes
Skin rash

PregnancyFDA N

Not recommended. Concentrated isoflavones show estrogen-like activity; pregnancy safety data are absent. AEMPS classifies these products as do not use.

Breastfeeding

Not recommended. Isoflavones transfer into milk; the infant may theoretically experience estrogenic effects. eLactancia rates concentrated extracts as moderate-high risk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Red clover (Trifolium pratense) used for?

Red clover (Trifolium pratense) is evaluated for the following indications with varying evidence strength: Hot flashes and night sweats (evidence tier D), Breast cancer prevention via supplements (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Red clover (Trifolium pratense)?

Common side effects of Red clover (Trifolium pratense) (≥ 1 in 100): Nausea and gastrointestinal discomfort, Headache, Menstrual cycle changes, Skin rash. See the Safety section for uncommon and serious reactions.

Is Red clover (Trifolium pratense) safe during pregnancy?

FDA category N. Not recommended. Concentrated isoflavones show estrogen-like activity; pregnancy safety data are absent. AEMPS classifies these products as do not use.

Is Red clover (Trifolium pratense) compatible with breastfeeding?

Not recommended. Isoflavones transfer into milk; the infant may theoretically experience estrogenic effects. eLactancia rates concentrated extracts as moderate-high risk.

Who should not take Red clover (Trifolium pratense)?

Red clover (Trifolium pratense) is contraindicated in: Hypersensitivity to Trifolium pratense; History of hormone-receptor-positive (HR+) breast, ovarian or endometrial cancer; Pregnancy and lactation; Warfarin or other anticoagulants without INR monitoring (isoflavones may theoretically enhance the effect). Full list in the Safety section.

Mechanism of action

Indications

Hot flashes and night sweats

Individual decision

Sources

Safety

Contraindications

Hypersensitivity to Trifolium pratense
History of hormone-receptor-positive (HR+) breast, ovarian or endometrial cancer
Pregnancy and lactation
Warfarin or other anticoagulants without INR monitoring (isoflavones may theoretically enhance the effect)

Serious adverse effects

Bleeding when combined with anticoagulants
Estrogen-dependent stimulation of HR+ tumours (theoretical)
Severe allergic reactions

Common adverse effects

Nausea and gastrointestinal discomfort
Headache
Menstrual cycle changes
Skin rash

PregnancyFDA N

Not recommended. Concentrated isoflavones show estrogen-like activity; pregnancy safety data are absent. AEMPS classifies these products as do not use.

Breastfeeding

Not recommended. Isoflavones transfer into milk; the infant may theoretically experience estrogenic effects. eLactancia rates concentrated extracts as moderate-high risk.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Frequently asked

What is Red clover (Trifolium pratense) used for?

What are the side effects of Red clover (Trifolium pratense)?

Is Red clover (Trifolium pratense) safe during pregnancy?

FDA category N. Not recommended. Concentrated isoflavones show estrogen-like activity; pregnancy safety data are absent. AEMPS classifies these products as do not use.

Is Red clover (Trifolium pratense) compatible with breastfeeding?

Not recommended. Isoflavones transfer into milk; the infant may theoretically experience estrogenic effects. eLactancia rates concentrated extracts as moderate-high risk.

Who should not take Red clover (Trifolium pratense)?