What Is Red Clover?

Red clover (Trifolium pratense) is an herb that belongs to the legume family, which also includes peas and beans. In herbal medicine, red clover is typically used to treat respiratory issues (such as asthma, whooping cough, and bronchitis), skin disorders (such as eczema and psoriasis), inflammatory conditions like arthritis, and women's health problems (such as menopausal and menstrual symptoms).

Red clover's brightly colored flowers contain many nutrients including calcium, chromium, magnesium, niacin, phosphorus, potassium, thiamine, and vitamin C. They're also a rich source of isoflavones. These are compounds that act as phytoestrogens—plant chemicals similar to the female hormone estrogen. Isoflavone extracts are touted as dietary supplements for high cholesterol and osteoporosis in addition to menopausal symptoms.

What Is Red Clover Used For?

In alternative medicine, red clover is said to help with the following conditions. Note, however, that research hasn't shown that the herb is conclusively effective for these or any other health concerns.

Menopausal Symptoms

A number of small studies have been done to see if red clover may help relieve the discomforts of menopause, especially hot flashes. Though you may hear some anecdotal support for this, there has been no conclusive evidence to back it up.

In fact, a research review conducted in 2013 notes that phytoestrogen treatments (including red clover) are not proven to effectively alleviate menopausal symptoms.

Bone Loss

Research is ongoing as to whether isoflavones lower the loss of bone mineral density in postmenopausal women. Red clover is one source of supplements used in some studies.

A review done in 2016 concluded there may be some beneficial effects on bone health, while a 2017 review found that different formulations of red clover may be effective or ineffective.

Cancer

Preliminary research suggests that red clover may help reduce the risk of prostate cancer. In a 2009 study of prostate cancer cells, scientists found that treatment with red clover led to a decrease in the prostate-specific antigen (PSA), a protein found at elevated levels in men with prostate cancer.

Heart Disease

A few clinical trials have looked at the effects of red clover on the development of risk factors for heart disease in postmenopausal women, with no strong evidence that it helps, reports Memorial Sloan Kettering Cancer Center.

Selection and Preparation

Red clover is available in a variety of preparations, including teas, tinctures, tablets, capsules, liquid extract, and extracts standardized to specific isoflavone contents. It's not always clear, however, that a product contains the promised isoflavone content.

One study found large differences between red clover products in this regard—differences that can significantly impact absorption rates, permeability, and metabolism of various isoflavones within these products.

Sometimes red clover is the sole ingredient in products, but it's also often available mixed with other herbs. When using commercial products, follow the package instructions carefully.

Extracts of red clover isoflavones are different from the whole herb, and in fact, represent only a small, highly concentrated—and likely bioactive—part of the entire herb. As the researcher in the product study mentioned above notes, "the widespread use of self-administered isoflavones is somewhat unsettling since much remains to be proven including efficacy and possible side effects."

Making Red Clover Tea

You can also make tea from dried flower heads. Some proponents claim that to get the full benefit of red clover you need to use the whole flower, and not commercial red clover isoflavones, which many studies use.

To make a tea, use one to three teaspoons of dried red clover flowers for every cup of simmering (not boiling) water. Let steep for 15 minutes. Drink up to three cups of tea a day.

Possible Side Effects

Women who are pregnant or breastfeeding, along with anyone with hormone-sensitive cancers, which may be accelerated by phytoestrogens, should avoid red clover.

Interactions

Red clover has blood-thinning abilities and can increase the effects of anticoagulant and antiplatelet drugs. Avoid taking it with blood thinners like Coumadin (warfarin) and stop taking it at least two weeks prior to surgery.

The herb may also interact with birth control pills due to the hormone-like actions of its isoflavones.

Red clover causes toxic effects when taken with methotrexate, a drug used to treat certain types of cancer and to control severe psoriasis or rheumatoid arthritis.

If you're considering using red clover, make sure to consult your physician first to avoid problematic drug-herb interactions.

Important Reminders About Supplements

People often ask if dietary supplements are safe. It's important to keep in mind that supplements haven't been tested for safety and dietary supplements are largely unregulated. As noted earlier, in some cases, a product may deliver doses that differ from the specified amount for each herb. In other cases, it may be contaminated with other substances such as metals.

When shopping for supplements, look for products that have been certified by ConsumerLabs, The U.S. Pharmacopeial Convention, or NSF International. These organizations don't guarantee a product is safe or effective, but they indicate that it's undergone testing for quality.