Ackerklee (German), beebread, cow clover, genistein, ICE, isoflavone, isoflavone clover extract, meadow clover, phytoestrogen, Promensil®, purple clover, Rimostil®, Rotklee (German), trefle des pres (French), trefoil, Trinovin®, wild clover.
Red clover is a legume, which like soy contains "phytoestrogens" (plant-based chemicals that are similar to estrogen and may act in the body like estrogen or may actually block the effects of estrogen). Red clover was traditionally used to treat asthma, pertussis (whooping cough), cancer, and gout. In modern times, isoflavone extracts of red clover are most often used to treat menopausal symptoms, as an alternative hormone replacement therapy, for high cholesterol, or to prevent osteoporosis. However, at this time, there are no high-quality human studies supporting the use of red clover for any medical condition.
Cardiovascular - blood flow:
Red clover has been shown to improve the flow of blood through arteries and veins. However, there is limited study in this area and more research is needed before a conclusion can be drawn.
Red clover has been studied in patients with type 2 diabetes to determine potential benefits in diabetic complications such as high blood pressure and narrowing of the arteries and veins. Further research is needed before a strong recommendation can be made.
Red clover has not been clearly shown to have beneficial effects on blood cholesterol levels. Due to conflicting study results, further research is needed in this area before a recommendation can be made.
Hormone replacement therapy (HRT):
Laboratory research suggests that red clover isoflavones have estrogen-like activity. However, there is no clear evidence that isoflavones share the possible benefits of estrogens (such as effects on bone density). In addition, hormone replacement therapy itself is a controversial topic, with recent research reporting that the potential harm may outweigh any benefits.
Red clover isoflavones are proposed to reduce symptoms of menopause (such as hot flashes), and are popular for this use. Blood pressure and triglyceride levels may be lowered. However, most of the available human studies are poorly designed and short in duration (less than 12 weeks of treatment). As results of published studies conflict with each other, more research is needed before a clear conclusion can be drawn.
It is not clear if red clover isoflavones have beneficial effects on bone density. Most studies of isoflavones in this area have looked at soy, which contains different amounts of isoflavones, as well as other non-isoflavone ingredients. More research is needed before a recommendation can be made.
Red clover isoflavones may have estrogen-like properties in the body, and have been proposed as a possible therapy in prostate cancer and related hot flashes. Some isoflavones have also been shown in laboratory studies to have anti-cancer properties. Because there is a lack of well-designed human research in this area, a strong recommendation cannot be made.
Prostate enlargement (benign prostatic hypertrophy):
There is only limited study of red clover for benign prostatic hypertrophy (enlarged prostate). More research is needed before a firm conclusion can be drawn.
Various doses of red clover isoflavones have been used to treat conditions. For instance, for benign prostatic hypertrophy (enlarged prostate), a dose of 40 milligrams of red clover isoflavones per day (Trinovin®) has been studied. For breast cancer prevention, a red clover-derived isoflavone tablet containing 26 milligrams biochanin A, 16 milligrams formononetin, 1 milligram genistein, and 0.5 milligram of daidzein has been studied.
For cardiovascular disease, a dose of 86 milligrams per day for one month has been studied. For diabetes, 50 milligrams and 86 milligrams per day of red clover isoflavones per day have been studied for diabetic complications. For high cholesterol, 28-86 milligrams of red clover isoflavones per day (Rimostil®), or 80 milligrams of red clover isoflavones per day (Promensil®), have been studied. For hormone replacement, a dose of 40-160 milligrams of red clover isoflavones per day (Promensil®) has been studied. Rimostil® (57 milligrams of red clover) has also been used. For osteoporosis, a dose of 40 milligrams of red clover isoflavones per day (Promensil®) has been studied.
There is not enough scientific evidence to recommend use of red clover in children.
People with known allergies or reactions to products containing red clover or isoflavones should avoid taking red clover.
A small number of human studies using red clover extracts have all reported good tolerance, without serious side effects after up to one year of treatment. In theory, based on the estrogen-like action of red clover seen in laboratory studies, side effects may include weight gain or breast tenderness, although these have not been reported clearly in humans. In theory, menstrual changes and increased uterus cell growth (endometrial hyperplasia) may also occur, although preliminary short-term studies (less than six months) have found no increases in uterus wall (endometrial) thickness with red clover. Red clover may affect hormonal levels of gonadotropin releasing hormone (GrH), follicle stimulating hormone (FSH), and leutinizing hormone (LH), although early research has not found significant change in FSH or LH levels.
In theory, red clover may increase the risk of bleeding. However, there are no reliable human reports of bleeding with red clover. Caution is advised in patients with bleeding disorders, taking drugs that may increase the risk of bleeding, or scheduled for surgery. Dosing adjustments may be necessary.
Red clover has been studied for lowering blood sugar with inconclusive results. Caution is warranted until further research is available.