Side Effects of Red Clover

Side Effects of Red Clover

Red clover is known for its ability to treat menopausal symptoms. This and many more benefits render it quite useful for human ailments. However, it has its own set of side effects, which must be monitored carefully to reduce the risk of developing serious complications.
HolisticZine Staff
Red clover or Trifolium pratense belongs to the family 'Fabaceae' and is a native herbaceous, perennial plant of northwest Africa, Western Asia and Europe, however, it is cultivated in many geographical regions. It is a short-lived plant which grows 20-80 cm tall, is found in many varieties and is known for its uses. It is generally used as a fodder crop and is known to improve soil fertility. Medicinal uses of red clover include treatment of menopausal symptoms, maintenance of acid-base balance in the vagina to facilitate conception, osteoporosis, cardiovascular diseases, cancers and many more.

Benefits of red clover are many, but we must not forget that even natural products can have some associated side effects. Before discussing them, let's have a look at its chemical composition.

Chemical Composition of Red Clover
  • Major Isoflavones: Formononetin, Genistein, Daidzein and Biochanin A
  • Other Isoflavones: Pratensein, Calycosin, Trifoside, Pseudobaptigenin, Prunetin and Glycitein
  • Flavones: Pectolinarin
  • Coumarins: Coumestrol, Coumarin and Medicagol
  • Other Constituents: Isorhamnetin glucosides, Procyanidin polymers and trans- and cis-Clovamide
The chemical composition clearly suggests that it contains a large amount of isoflavones and coumarins, which are known to cause related unwanted effects.

Red Clover Side Effects

Common Side Effects
Unwanted effects that are commonly observed in people taking regular dose of red clover are:
  • Difficulty in breathing
  • Wheezing
  • Headache
  • Muscle soreness
  • Nausea
  • Allergy
Even though these effects are common, they are not very serious and fade away with proper medical approach. However, one must not wait till the seriousness of the effect increases. Any observed side effect should be reported immediately to the doctor so that treatment can be provided right away.

Serious Side Effects
Effects listed under this category are observed, but in rare instances. These serious effects can be fatal if not taken care of. These include:

Infertility: It is found that animals grazing on red clover for a long period of time gradually turn infertile. However, this side effect is not studied in humans till date and no conclusions are established. The possibility of infertility cannot be ruled out in humans due to lack of relevant studies.

Liver Damage: This is another serious side effect that can possibly result due to red clover intake. Persons with liver damage display symptoms like dark-colored urine, abdominal pain, and appearance of yellowish marks on skin and cornea of the eye.

Vaginal Bleeding: The chemical constituents of red clover include isoflavones, which are known to produce estrogen-like effects in the body. This can alter menstrual cycle in women and cause overgrowth of uterine lining producing symptoms like vaginal spotting.

Interactions of Red Clover

The isoflavones or estrogen-like compounds of red clover are known to interact and interfere in the processing of certain drugs, which are acted upon by enzymes of the liver. That is why, any medication taken along with red clover must be informed to the doctor so that changes can be made, if required. People undergoing hormone replacement therapy, taking regular dose of estrogen, and birth-control pills must avoid red clover because its estrogen-like compounds may alter their efficacy. People taking anticoagulants must not use this herb because the coumarins present in it are natural blood thinners. Taking them along with other anticoagulants will simply accentuate blood thinning and may even result in internal bleeding. Red clover is also known to produce cancer in some individuals and interferes in the action of cancer-treating drug, tamoxifen.

Note: The use of red clover is contraindicated in pregnant and breastfeeding women.

Red clover is sold as a dietary supplement in the United States and is not regulated. It is marked under the category of "generally recognized as safe", and some health drinks and teas include this herbal plant as an ingredient. It is a good remedy for menopausal symptoms, but is criticized for adding estrogen-like compounds in the body. If in doubt about whether to use it or not, it is better to opt for non-estrogenic herbs which are free from such problems.