Pueraria mirifica is a plant that grows in Thailand and other parts of Southeast Asia. It’s also known as Kwao Krua.
For over 100 years, the roots of Pueraria mirifica have been used in traditional Thai medicine to promote youthfulness and rejuvenation in both men and women ().
Certain plant compounds known as phytoestrogens make up the primary active components of Pueraria mirifica. They mimic the hormone estrogen in your body ().
Due to its strong estrogenic effect, Pueraria mirifica is sold as an herbal supplement — primarily used to treat symptoms of menopause, though research suggests that the plant may offer other health benefits as well.
Here are 7 emerging health benefits of Pueraria mirifica.
Estrogen is a steroid hormone involved in many of your body’s functions. In women, one of its primary roles is the development of sexual characteristics and regulation of mood and the menstrual cycle ().
As women age, the production of estrogen decreases, which may lead to uncomfortable physical symptoms.
Phytoestrogens are plant compounds that mimic the behavior of estrogen. As Pueraria mirifica is rich in phytoestrogens, it’s often used to relieve symptoms of menopause ().
Small human studies have demonstrated significant improvements in various menopausal symptoms — such as hot flashes, vaginal dryness, irritability, and irregular or absent periods — after treatment with Kwao Krua (3, , ) .
However, a 2018 review found that current data on the efficacy of the herb for these purposes was largely inconclusive due to a lack of standardization of the supplement and overall poor study designs ().
At this point, more well-designed studies are needed to determine if Pueraria mirifica is a safe and effective treatment for symptoms of menopause.
Summary Several small studies have shown Pueraria mirifica to be an effective treatment for menopausal symptoms, but many of the study designs carry significant flaws, limiting the reliability of their results.
Pueraria mirifica may be an effective topical therapy for promoting the health of vaginal tissue and treating vaginal dryness.
One 28-day study in postmenopausal monkeys evaluated the effectiveness of a gel containing 1% Kwao Krua on vaginal tissue. The topically applied gel significantly improved the tissue’s health, pH, and skin tone ().
Similarly, a recent 12-week study in 71 postmenopausal women with various uncomfortable vaginal symptoms evaluated the efficacy of a Kwao Krua cream compared to a standard estrogen cream ().
The Kwao Krua cream significantly improved symptoms of vaginal irritation and dryness. Nonetheless, the study concluded that the estrogen cream was more effective overall ().
Though these results are promising, more research is needed to understand how the plant may be used to support vaginal health and whether its benefits are better than other conventional treatments.
Summary Some animal and human studies have resulted in improvements in various vaginal symptoms with topical use of Pueraria mirifica. More research is needed to evaluate whether it’s more beneficial than conventional treatments.
An inadequate supply of estrogen can lead to bone loss — which is a major health concern for menopausal and postmenopausal women ().
Early-stage animal research suggests that supplementing with Pueraria mirifica may improve bone health due to its estrogen-like compounds.
A study in estrogen-deficient mice evaluated the effect of Pueraria mirifica on preventing osteoporosis. Results revealed better preservation of bone mineral density in certain bones of the mice that received the highest doses of the plant supplement ().
Another study assessed the effect of oral Kwao Krua supplements on bone density and quality in postmenopausal monkeys over 16 months ().
Results indicated that the Kwao Krua group more effectively maintained bone density and quality compared to the control group ().
Both of these animal studies suggest that Kwao Krua may play a role in preventing osteoporosis. However, additional research is needed to understand if similar results could occur in humans.
Summary Animal studies suggest that supplementing with Pueraria mirifica may prevent bone loss in estrogen-deficient animals. More research is needed to evaluate whether the same results could occur in humans.
Antioxidants are chemical compounds that reduce levels of stress and oxidative damage within your body, which may otherwise cause disease.
Some test-tube research suggests that Pueraria mirifica may have antioxidant properties ().
Phytoestrogen compounds found in the plant may play a role in increasing and improving the function of certain antioxidants found within your body.
One study in estrogen-deficient mice compared the effect of Pueraria mirifica extract and synthetic estrogen supplements on antioxidant concentration in the liver and uterus ().
Results revealed that the mice who received Pueraria mirifica experienced significant increases in antioxidant levels, whereas no significant changes were observed in the mice who received the synthetic estrogen ().
Ultimately, more research is needed to understand whether Kwao Krua is effective for reducing oxidative stress and potentially preventing disease in humans.
Summary Some animal research suggests that compounds in Pueraria mirifica may improve antioxidant levels in the body, although this is yet to be confirmed in human studies.
Another possible health benefit of Pueraria mirifica is its potential to slow the growth of cancerous cells and tumors.
Some test-tube studies suggest that the plant and its phytoestrogen compounds may inhibit the growth of several breast cancer cell lines (, ).
Moreover, a study found a cancer-protective effect in mice after supplementing with a specific compound derived from Kwao Krua known as miroestrol ().
Though these results are promising, it’s still too early to make definitive claims regarding the role of this plant supplement in cancer prevention in humans. More research is needed.
Summary Some test-tube and animal research suggests that compounds present in Pueraria mirifica may prevent the growth of certain types of cancerous cells. However, human studies are needed to confirm these effects.
Pueraria mirifica may also benefit your heart health — especially since heart health may be affected by decreased estrogen levels during and after menopause.
Estrogen is involved in the metabolism of fats and sugars within your body. Reduced estrogen levels can negatively influence factors that affect your heart health, such as higher cholesterol, increased inflammation, and weight gain ().
One 90-day study in rabbits with low estrogen production on the effect of Pueraria mirifica on artery function found that the supplement significantly improved blood vessel function, compared to the control group ().
The plant may also improve heart health due to its potential effects on cholesterol levels.
HDL — or “good” cholesterol — plays a role in keeping your arteries free from plaque. Thus, higher levels of this type of cholesterol promote heart health.
Conversely, having higher levels of “bad” LDL cholesterol is associated with a greater risk of heart disease. Therefore, lower levels of this compound are favorable.
A 2-month study in 19 postmenopausal women concluded that taking Pueraria mirifica supplements increased HDL cholesterol by 34% and reduced LDL cholesterol by 17% ().
These studies point to a possible heart-protective effect of Pueraria mirifica in certain populations. At this point, larger human studies are needed to draw conclusions regarding the specific role the plant supplement may play in preventing heart disease.
Summary Some animal and human studies indicate that Pueraria mirifica may improve cholesterol profiles and blood vessel function. More research is needed to identify the exact benefits of the plant for preventing heart disease.
Estrogen plays an important role in maintaining a healthy brain and nervous system ().
Some research suggests that estrogenic compounds present in Kwao Krua may protect against the damage to your brain and nervous system that may occur as a result of decreased estrogen levels.
In one study, estrogen-deficient mice were treated with a compound derived from Kwao Krua called miroestrol. The mice given miroestrol experienced a significant reduction in mental decline and oxidative stress within the brain tissue ().
A separate study also saw a protective effect on the brain cells of mice with estrogen-related mental deficits who were treated with a Kwao Krua extract ().
Though it seems that Pueraria mirifica may have the potential to protect the nervous system, research exploring its role on brain health in humans is currently lacking.
Summary Some animal research suggests a protective role of Pueraria mirifica on nervous tissue of the brain. Before definitive conclusions can be drawn, human research is needed.
The pool of data on Pueraria mirifica is relatively small which makes it difficult to pinpoint an ideal dosage or fully assess the supplement for potential risks.
Most research has shown that doses of 25–100 mg seem safe with no apparent adverse reactions reported ().
In fact, very few negative side effects have been documented at all, but that doesn’t mean that taking the supplement is risk-free.
Pueraria mirifica is often marketed as a “safer” alternative to conventional hormone replacement therapies — which are known to come with serious side effects, including increased risk of cancer, blood clots, heart attacks, and stroke ().
Still, some experts believe that the plant supplement may have the same estrogenic strength as conventional hormonal therapies. Thus, you should be cautious if you choose to take it.
Always consult with your healthcare provider before taking any herbal supplement to treat a medical condition.
Summary Most research indicates that taking 25–100 mg doses of Pueraria mirifica is safe. Few adverse reactions have been reported so far, but data is limited.
Pueraria mirifica — or Kwao Krua — has long been used as a rejuvenation therapy in traditional Thai medicine practices.
It’s rich in phytoestrogens, plant compounds known for having strong estrogen-like effects.
Pueraria mirifica is frequently used as a supplement to treat conditions associated with low estrogen levels — especially related to menopause in women.
Research on this herbal supplement is limited. Thus, not much is known about its safety, though only a few negative effects have been reported.
Exercise caution and be sure to talk to your healthcare provider before adding Pueraria mirifica to your health and wellness routine.