Red clover (Trifolium pratense) is a flowering plant from the legume family, the same botanical group as peas and beans. You’ve probably seen it growing wild in meadows and fields across Europe and North America, recognisable by its distinctive pink-purple flower heads.

For centuries, traditional herbalists have used red clover to treat everything from skin conditions to respiratory problems. But in recent decades, it’s gained attention for a different reason entirely: its isoflavone content. These plant compounds can mimic oestrogen in the body, which is why red clover supplements have become popular among women seeking relief from menopausal symptoms.

The isoflavones in red clover, primarily biochanin A, formononetin, genistein, and daidzein, are similar to those found in soy products. Interestingly, the highest concentrations are found in the leaves and roots rather than the flowers, contrary to what many people assume 1.

So does red clover actually work? Let me walk through what the research shows.

1. Cardiovascular health effects

Heart disease develops gradually over years, often without obvious warning signs until something serious happens. The main culprits are well known: high blood pressure, elevated blood sugar, and problematic cholesterol levels. These factors damage blood vessel walls and reduce arterial flexibility over time.

Red clover isoflavones appear to influence cardiovascular health through multiple mechanisms. One study in menopausal women found that supplementation improved arterial compliance (basically how elastic your blood vessels are) by up to 23% over five weeks at doses of 40-80mg 2. More flexible arteries mean better blood flow and lower cardiovascular strain.

A separate double-blind trial involving 80 adults with normal blood pressure examined whether red clover could reduce arterial stiffness. The results showed improvements in vascular resistance, though blood pressure itself wasn’t affected 3.

My take: The arterial flexibility findings are interesting, but we’re talking about relatively small studies over short time periods. Whether these changes translate to fewer heart attacks or strokes down the road remains unknown. I wouldn’t rely on red clover alone for cardiovascular protection.

2. Blood lipid effects

Blood lipids, meaning cholesterol and triglycerides, are routine markers checked during health assessments. When levels stay elevated over years, fatty deposits can accumulate in artery walls, eventually causing blockages that lead to heart attacks or strokes. The tricky part is that high blood lipids rarely cause noticeable symptoms until significant damage has occurred.

A 12-week study of 252 menopausal women tested whether red clover extract could improve lipid profiles. The results were mixed: triglycerides dropped by 9.7%, but only in women who had elevated levels to begin with. For those with normal triglycerides, there was no meaningful change. Cholesterol levels weren’t significantly affected either way 4.

Some researchers have speculated that isoflavones work similarly to oestrogen’s protective effects on blood vessels. Oestrogen helps maintain healthy cholesterol ratios, which partly explains why cardiovascular disease risk increases in women after menopause. The theory is that plant oestrogens might partially compensate for this hormonal shift.

Reality check: A 9.7% drop in triglycerides sounds decent, but context matters. Lifestyle changes like reducing refined carbohydrates and increasing exercise can achieve far larger improvements. Red clover might offer modest additional benefit for some people, but it’s not a substitute for diet and activity changes.

3. Bone density effects

Osteoporosis affects millions of older adults, particularly women. As bone density declines with age, fractures become increasingly likely. The spine, hips, and wrists are most vulnerable. A hip fracture in an elderly person often leads to months of immobility and significant loss of independence.

The rationale for testing red clover in osteoporosis is straightforward: oestrogen helps maintain bone density, and isoflavones might partially mimic this effect. Unfortunately, the clinical evidence has been underwhelming.

A Cochrane systematic review examined all available trials of phytoestrogens, including red clover, for bone health. The conclusion was that current evidence doesn’t support using these supplements to prevent or treat osteoporosis 5. Most studies were small, short-term, or had methodological limitations.

For context, foods and supplements beneficial for osteoporosis include calcium, vitamin D, and in some cases prescription medications. Red clover doesn’t make most experts’ recommended lists.

My assessment: I’d be sceptical of marketing claims about red clover and bone health. The theoretical rationale exists, but the clinical trials haven’t delivered convincing results. If you’re concerned about osteoporosis, stick with proven approaches like adequate calcium intake, weight-bearing exercise, and discussing options with your doctor.

4. Menopausal symptom relief

This is the application that generates the most interest, and frankly, the most debate. Menopause typically occurs around age 50, when menstrual cycles end as ovarian function declines. The hormonal shifts can trigger a range of uncomfortable symptoms: hot flushes, night sweats, mood swings, sleep disturbances, and vaginal dryness.

Hormone replacement therapy (HRT) effectively treats these symptoms but carries risks that concern many women. That’s driven interest in alternatives like black cohosh and evening primrose oil, as well as red clover.

The research on red clover for hot flushes has produced frustratingly inconsistent results. An early large controlled study using a branded extract (Promensil) found no significant improvement in hot flushes or other menopausal symptoms compared to placebo 6. This was a well-designed trial, and the negative result dampened enthusiasm considerably.

However, subsequent studies have been more encouraging. A 90-day trial reported that 80mg daily of red clover extract reduced Kupperman Index scores (a standard measure of menopausal symptoms) by 75.4%. Hot flushes and night sweats improved by up to 70% 7. Another study found 33% improvement in hot flushes within just three weeks, along with reductions in the Greene Climacteric Scale, which measures overall menopausal symptom severity 8.

Why such different results? Study design matters enormously. Factors like the specific red clover extract used, the dose, treatment duration, and how participants were selected all influence outcomes. The placebo response in menopause trials is also notoriously high, sometimes reaching 30-40%, which makes it harder to detect genuine treatment effects.

The catch: I genuinely don’t know whether red clover will help any individual woman with hot flushes. The evidence is a mixed bag. Some women swear by it; others notice nothing. If you’re curious, a 12-week trial at 40-80mg daily seems reasonable based on the positive studies. Just don’t expect dramatic results, and consider that you might be experiencing a placebo effect if you do improve.

5. Mood and emotional wellbeing

Menopause doesn’t just affect the body. Many women experience increased anxiety, irritability, low mood, and even clinical depression during this transition. Hormonal fluctuations disrupt neurotransmitter systems, and sleep disturbances (often caused by night sweats) compound the problem.

A study examining mood outcomes found that 80mg of red clover extract daily for 90 days reduced anxiety and depression scores by up to 76% on validated questionnaires 9. Another trial reported substantial improvements in self-rated emotional state, with participants scoring 66-68 points better on visual analogue scales compared to just 8-15 points in the placebo group 10.

These are substantial effect sizes if accurate. However, mood is highly susceptible to placebo effects and study participation itself can improve wellbeing through increased attention and expectation of benefit.

Worth noting: If you’re experiencing significant depression or anxiety during menopause, red clover probably isn’t sufficient treatment. Talk to your GP about options, which might include counselling, antidepressants, or HRT depending on your situation and preferences.

6. Skin, hair and nail quality

Oestrogen influences skin health in ways that become apparent after menopause. Reduced oestrogen leads to decreased collagen production, thinner skin, reduced moisture retention, and slower wound healing. Hair and nails may also become more brittle.

One double-blind controlled study found that oral red clover improved overall skin condition in menopausal women, with particular improvements in moisture content and texture. The overall improvement score was approximately 18 points on a 100-point scale, compared to just 5 points in the placebo group. The same trial noted some improvement in hair and nail quality as well 10.

For those interested in skin health supplements, collagen products have more extensive research backing them, though both approaches have limitations.

In practice: An 18-point improvement sounds meaningful on paper, but skin changes are subjective and difficult to measure objectively. I’d consider red clover for skin health as a secondary potential benefit rather than a primary reason to take it.

Side effects and safety concerns

According to the US FDA, red clover is “Generally Recognised as Safe” (GRAS) as a food ingredient. However, concentrated supplement forms may carry different risk profiles, and long-term safety data remains limited.

Commonly reported side effects include headache, nausea, and skin rash. Most people tolerate red clover well at standard supplement doses.

The more serious concern relates to its oestrogenic activity. Plant oestrogens are weaker than human oestrogen, but they still interact with oestrogen receptors throughout the body. That matters for several groups.

Safety precautions (6 contraindications)

1. Hormone-sensitive cancers: Women with a history of breast cancer, endometrial cancer, ovarian cancer, or uterine fibroids should avoid red clover. The oestrogenic effects could theoretically stimulate hormone-sensitive tissues, though this hasn’t been definitively proven harmful.

2. Pregnancy and breastfeeding: The hormonal effects make red clover unsuitable during pregnancy or while nursing. Insufficient safety data exists for these populations.

3. Bleeding disorders and anticoagulant use: Red clover contains coumarins, compounds with mild blood-thinning properties. People taking warfarin, aspirin, or other anticoagulants should avoid red clover or use it only under medical supervision. Similarly, those with clotting disorders or scheduled for surgery should stop supplementation at least two weeks beforehand.

4. Hormone replacement therapy and contraceptives: Don’t combine red clover with HRT or hormonal contraceptives without medical guidance. The combined oestrogenic effects could interfere with these medications’ effectiveness or increase side effect risks.

5. Liver or kidney impairment: Safety in people with compromised liver or kidney function hasn’t been established. These organs process and eliminate supplements from the body, so impairment could lead to accumulation.

6. Infants and children: Red clover supplements are not appropriate for paediatric use. The oestrogenic effects could potentially disrupt normal hormonal development.

Drug interactions to consider

Beyond anticoagulants, red clover may interact with medications metabolised by certain liver enzymes (cytochrome P450 system). This includes many common drugs. If you take prescription medications regularly, discuss red clover supplementation with your pharmacist or doctor before starting.

Dosage and forms

Most clinical trials have used standardised red clover extracts providing 40-80mg of isoflavones daily. Supplements are available as capsules, tablets, liquid extracts, and teas. The isoflavone content varies considerably between products, so check labels carefully.

For menopausal symptoms, studies typically lasted 12 weeks or longer before significant effects were observed. Patience is required.

Summary

Red clover contains isoflavones that can produce mild oestrogenic effects in the body. The research suggests potential benefits for menopausal symptoms and possibly cardiovascular health, though evidence quality varies. Bone health claims aren’t well supported by current data.

The supplement appears safe for most healthy adults at standard doses, but significant contraindications exist for pregnant women, those with hormone-sensitive conditions, and people taking certain medications.

Whether red clover is worth trying depends on your individual circumstances. For menopausal hot flushes, it’s a reasonable option if you want to avoid HRT or haven’t found other natural approaches helpful. Just keep expectations realistic. The research is genuinely mixed, and you may or may not notice benefit.

References

Saviranta NM, et al. Red clover (Trifolium pratense L.) isoflavones: determination of concentrations by plant stage, flower colour, plant part and cultivar. J Sci Food Agric. 2008.
Nestel PJ, et al. Isoflavones from red clover improve systemic arterial compliance but not plasma lipids in menopausal women. J Clin Endocrinol Metab. 1999.
Teede HJ, et al. Dietary soy has both beneficial and potentially adverse cardiovascular effects: a placebo-controlled study in men and postmenopausal women. J Clin Endocrinol Metab. 2001.
Knight DC, et al. The effect of Promensil, an isoflavone extract, on menopausal symptoms. Climacteric. 1999.
Lagari VS, Levis S. Phytoestrogens for menopausal bone loss and climacteric symptoms. J Steroid Biochem Mol Biol. 2014.
Baber RJ, et al. Randomized placebo-controlled trial of an isoflavone supplement and menopausal symptoms in women. Climacteric. 1999.
Hidalgo LA, et al. The effect of red clover isoflavones on menopausal symptoms, lipids and vaginal cytology in menopausal women. Gynecol Endocrinol. 2005.
van de Weijer PH, Barentsen R. Isoflavones from red clover (Promensil) significantly reduce menopausal hot flush symptoms compared with placebo. Maturitas. 2002.
Lipovac M, et al. The effect of red clover isoflavone supplementation over vasomotor and menopausal symptoms in postmenopausal women. Gynecol Endocrinol. 2012.
Chedraui P, et al. Effect of Trifolium pratense-derived isoflavones on the lipid profile of postmenopausal women with increased body mass index. Gynecol Endocrinol. 2008.