Two plants have been added to Examine database, both of which are traditional Thai medicines and both of which have their tubers used for medicine. Their bio activities are interesting but for the most part still being researched, but their existence and usage is somewhat poetic.
The two herbs in question are the confirmed estrogen Pueraria Mirifica and androgenic Butea Superba. These tubers are called White Kwao Krua and Red Kwao Krua respectively, are visually similar unless otherwise disturbed (in which case, Butea Superba secretes a red liquid owing to its common name), and both have a history of usage in Thai medicine for revitalizing older individuals (of which the benefits are gendered; ‘Kwao Krua’ in general is a term given to revitalizing agents it seems while White and Red are recommended for women and men respectively).
Both of these tubers appear to actually contain compounds that act directly on the receptors in question, circumventing the need to actually increase the hormone by acting as phytohormones themselves (phytoestrogens are well talked about, phytoandrogens are next to never talked about).
White Kwao Krua has a cluster of basic phytoestrogens including soy isoflavones in high quantities, yet these are not the reason for its estrogenicity. Estrogenic effects of this tuber come from a class of molecules called Chromenes; the ‘main’ chromene, Miroestrol, has been noted to be about a quarter as potent as the most powerful endogenous estrogen (17β-Estradiol). The related compound, Deoxymiroestrol, is about ten-fold more potent than Miroestrol and likely more potent than 17β-Estradiol itself on a weight basis (they haven’t been directly compared, but the math leads to that conclusion). It has been shown numerous times to have estrogen effects in both rats and prime apes, although the human studies currently using White Kwao Krua are less than optimal in study design.
Butea Superba (Red Kwao Krua) is not as well researched. It shares similar historical renown as White Kwao Krua except for men, but the androgenic molecule has not yet been confirmed; the androgenic effects per se have been confirmed in mouse and rat models of both genders and seem to work via the receptor itself rather than increasing testosterone. No study has attempted to compare the potency of Butea Superba on the receptor against more well known agonists such as testosterone itself (so such a nice conclusion on ‘X as potent as testosterone’ cannot be made right now).
As for the third Kwao Krua, known as Black Kwao Krua and bearing the botanical name of Mucuna collettii (not Mucuna Prurience; totally different plant) is incredibly under researched and no conclusions can be made on the third member of this party at this time.
Overall, we have two hormonal active tuber vegetables that are also common supplements; their history is intertwined in Thai medicine and they both appear to have efficacy in hormonal signalling. Their existence is somewhat poetic, and their bio activities are understudied but potentially worth looking into more.
7 Emerging Benefits of Pueraria mirifica
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 (1Trusted Source).
Certain plant compounds known as phytoestrogens make up the primary active components of Pueraria mirifica. They mimic the hormone estrogen in your body (1Trusted Source).
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.
1. Relieves Menopausal Symptoms
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 (2Trusted Source).
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 (1Trusted Source).
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, 4Trusted Source, 5Trusted Source) .
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 (6Trusted Source).
At this point, more well-designed studies are needed to determine if Pueraria mirifica is a safe and effective treatment for symptoms of menopause.
2. May Support Vaginal Health
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 (7Trusted Source).
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 (8Trusted Source).
The Kwao Krua cream significantly improved symptoms of vaginal irritation and dryness. Nonetheless, the study concluded that the estrogen cream was more effective overall (8Trusted Source).
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.
3. Promotes Bone Health
An inadequate supply of estrogen can lead to bone loss — which is a major health concern for menopausal and postmenopausal women (9Trusted Source).
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 (10Trusted Source).
Another study assessed the effect of oral Kwao Krua supplements on bone density and quality in postmenopausal monkeys over 16 months (11Trusted Source).
Results indicated that the Kwao Krua group more effectively maintained bone density and quality compared to the control group (11Trusted Source).
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.
4. Improves Antioxidant Activity
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 (12Trusted Source).
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 (13Trusted Source).
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 (13Trusted Source).
Ultimately, more research is needed to understand whether Kwao Krua is effective for reducing oxidative stress and potentially preventing disease in humans.
5. May Have Anticancer Effects
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 (14Trusted Source, 15Trusted Source).
Moreover, a study found a cancer-protective effect in mice after supplementing with a specific compound derived from Kwao Krua known as miroestrol (16Trusted Source).
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.
6. May Promote Heart Health
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 (17Trusted Source).
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 (18Trusted Source).
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% (19Trusted Source).
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.
7. May Support Brain Health
Estrogen plays an important role in maintaining a healthy brain and nervous system (20Trusted Source).
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 (21Trusted Source).
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 (22Trusted Source).
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.