Pueraria mirifica is a plant that grows in Thailand and other parts of Southeast Asia. It is 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 men and women ().

Certain plant compounds called phytoestrogens constitute the main 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, although research suggests the herb may also offer other health benefits.

Here are 7 emerging health benefits of Pueraria mirifica.

1. Relieves Menopausal Symptoms

Estrogen is a steroid hormone involved in many functions in your body. In women, one of its main roles is the development of sexual characteristics and the regulation of mood and the menstrual cycle ().

As women age, estrogen production declines, which can lead to uncomfortable physical symptoms.

Phytoestrogens are plant compounds that mimic the behavior of estrogens. As Pueraria mirifica is rich in phytoestrogens, it is often used for ().

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 (, , ) .

However, a 2018 review found that current data on the herb's effectiveness 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 whether Pueraria mirifica is a safe and effective treatment for menopausal symptoms.

Summary Several small studies have shown Pueraria mirifica may be an effective treatment for menopausal symptoms, but many study designs have significant flaws, limiting the reliability of their results.

2. May Support Vaginal Health

Pueraria mirifica may be an effective topical therapy to promote healthy vaginal tissue and treat vaginal dryness.

A 28-day study in postmenopausal monkeys evaluated the effectiveness of a gel containing 1% Kwao Krua on vaginal tissues. The topically applied gel significantly improved health, pH and ().

Similarly, a recent 12-week study in 71 postmenopausal women with various uncomfortable vaginal symptoms evaluated the effectiveness of a Kwao Krua cream compared to a standard estrogen cream ().

Kwao Krua Cream significantly improved symptoms of vaginal irritation and dryness. Nonetheless, the study concluded that estrogen cream was more effective overall ().

While these results are promising, more research is needed to understand how the herb can 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. Further research is needed to assess whether it is more beneficial than conventional treatments.

3. Promotes healthy bones

Insufficient estrogen intake can lead to bone loss, a major health problem for menopausal and postmenopausal women ().

Early animal research suggests that supplementation with Pueraria mirifica may improve due to its estrogen-like compounds.

A study in estrogen-deficient mice evaluated the effect of Pueraria mirifica on the prevention of osteoporosis. The results revealed better preservation of bone mineral density in some bones of mice that received the highest doses of the plant supplement ().

Another study evaluated the effect of oral Kwao Krua supplements on bone density and quality in postmenopausal monkeys over 16 months ().

The results indicated that the Kwao Krua group maintained bone density and quality more effectively compared to the control group ().

These two animal studies suggest that Kwao Krua may play a role in preventing osteoporosis. However, more research is needed to understand whether similar results could occur in humans.

Summary Animal studies suggest that supplementation with Pueraria mirifica may prevent bone loss in estrogen-deficient animals. Further research is needed to assess whether the same results could occur in humans.

4. Improves Antioxidant Activity

Antioxidants are chemical compounds that reduce stress levels and oxidative damage in your body that could otherwise cause disease.

Some test tube research suggests that Pueraria mirifica may have antioxidant properties ().

Compounds found in the plant may play a role in increasing and improving the function of certain antioxidants found in your body.

A study on estrogen-deficient mice compared the effect of Pueraria mirifica extract and synthetic estrogen supplements on the concentration of antioxidants in the liver and uterus ().

The results revealed that mice that received Pueraria mirifica experienced significant increases in levels, while no significant changes were observed in mice that received the synthetic estrogen ().

Ultimately, more research is needed to understand whether Kwao Krua is effective in reducing oxidative stress and potentially preventing disease in humans.

Summary Some animal research suggests that the compounds in Pueraria mirifica may improve antioxidant levels in the body, although this remains to be confirmed in human studies.

5. May have anti-cancer effects

Another possible health benefit of Pueraria mirifica is its potential to slow the growth of cancer 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 (, ).

Additionally, one study found one in mice after supplementation with a specific compound derived from Kwao Krua known as miroestrol ().

Although these results are promising, it is still too early to definitively affirm the role of this plant supplement in the prevention of cancer 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 cancer cells. However, human studies are needed to confirm these effects.

6. May Promote Heart Health

Pueraria mirifica can also benefit your – especially since heart health can be affected by decreased estrogen levels during and after menopause.

Estrogen is involved in the metabolism of fats and sugars in your body. Reduced estrogen levels can negatively influence factors that affect your heart health, such as higher cholesterol, increased inflammation, and weight gain ().

A 90-day study in rabbits with low estrogen production on the effect of Pueraria mirifica on arterial function found that the supplement significantly improved blood vessel function, compared to the control group ().

The herb may also improve heart health due to its potential effects on .

HDL – or “good” cholesterol – plays a role in maintaining plaque in your arteries. So, 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 of 19 postmenopausal women concluded that taking Pueraria mirifica supplements increased HDL cholesterol by 34% and reduced LDL cholesterol by 17% ().

These studies indicate a possible cardiac protective effect of Pueraria mirifica in certain populations. At this point, larger human studies are needed to draw conclusions regarding the specific role the herbal 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 in preventing heart disease.

7. May Support Brain Health

Estrogen plays an important role in maintaining a healthy nervous system and ().

Some research suggests that estrogenic compounds found in Kwao Krua may protect against damage to your brain and nervous system that can 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. Mice given miroestrol experienced a significant reduction in mental decline and oxidative stress in brain tissue ().

A separate study also found a protective effect on the brain cells of mice with estrogen-related mental deficits that were treated with Kwao Krua extract ().

Although 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 the nervous tissue of the brain. Before definitive conclusions can be drawn, human research is necessary.

Suggested dosage and possible side effects

The data pool on Pueraria mirifica is relatively low, making it difficult to identify an ideal dosage or fully evaluate the supplement for potential risks.

Most research has found that doses of 25 to 100 mg appear safe and no apparent adverse effects have been reported ().

In fact, very few negative side effects have been documented, but that doesn't mean taking the supplement is risk-free.

Pueraria mirifica is often marketed as a “safer” alternative to conventional hormone replacement treatments – which are known to cause serious side effects, including an increased risk of cancer, blood clots, heart attacks and strokes ().

Still, some experts believe that the herbal supplement may have the same estrogenic strength as the conventional one. So, you need to be careful if you choose to take it.

Always consult your health care provider before taking any herbal supplement to treat a medical problem.

Summary Most research indicates that taking doses of 25 to 100 mg of Pueraria mirifica is secure. Few side effects have been reported so far, but data are limited.

The bottom line

Pueraria mirifica – or Kwao Krua – has long been used in traditional Thai medicine practices.

It is rich in phytoestrogens, plant compounds known to have powerful estrogen-like effects.

Pueraria mirifica is frequently used as a supplement to treat conditions associated with low estrogen levels, particularly in women.

Research on this herbal supplement is limited. Thus, not much is known about its safety, although 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 well-being routine.