red clover
Meaning of red clover: A meadow legume sold for hot flashes because its isoflavones loosely mimic estrogen, on evidence that has stayed thin and mixed.
Definition of red clover
Red clover is a flowering legume, Trifolium pratense, grown widely as pasture and hay and long used in folk medicine. Its dried flower heads contain isoflavones, plant compounds shaped closely enough to estrogen to attach weakly to the same receptors. Extracts standardized for those isoflavones are sold as supplements, marketed mostly for symptoms around menopause.
What is a phytoestrogen?
A plant compound built on a chemical frame similar enough to estrogen that it can occupy an estrogen receptor. The fit is poor, so the effect is much weaker than the body's own hormone, and it can work in either direction: where estrogen levels are low the compound adds a faint signal, and where they are high it competes and can blunt one. Red clover supplies several of these at once, in a mixture close to what soy provides, which is why the two are usually discussed together.
What is it taken for, and does it work?
Hot flashes and night sweats around menopause account for most use, with smaller claims made for bone density, cholesterol and skin. Trials have been run repeatedly and the pattern has been consistent in an unhelpful way: individual studies disagree, effects when found are small, and the response in placebo groups is large, because hot flashes fluctuate on their own. Pooled analyses have not settled it. Nothing here approaches the effect of menopausal hormone therapy, and the older claim of anticancer activity rests on laboratory work rather than results in people.
How does it compare with other herbal preparations?
| Preparation | Marketed for | Active fraction |
|---|---|---|
| Red clover | Menopausal symptoms | Isoflavones |
| Soy extract | Menopausal symptoms | Isoflavones, similar profile |
| Black cohosh | Menopausal symptoms | Not an estrogen mimic |
| Purple coneflower | Colds | Unrelated compounds |
The estrogen-like action is also the source of the main caution attached to it. Because these compounds engage estrogen receptors, the preparation is treated as an open question in hormone-sensitive breast and uterine disease, and it may interact with medicines acting on the same receptors or with drugs that thin the blood. Strength varies between brands, since supplements are not standardized the way a prescribed medicine is.
Also known as
Used in a sentence
The patient reported taking a red clover extract for menopausal symptoms.
Good to know
The isoflavones in red clover act on estrogen receptors, so preparations are regarded as an open question in hormone-sensitive breast and uterine disease, and content varies between products because supplement strength is not standardized.