IngredientsKaempferia parviflora, known as Thai black ginger, Thai ginseng, or krachai dum, is an herbaceous plant in the family Zingiberaceae, native to Thailand. Its full taxonomic authority is Kaempferia parviflora Wall. ex Baker, placing it in the large and diverse monocot family Zingiberaceae, which also encompasses culinary staples such as common ginger (Zingiber officinale), turmeric (Curcuma longa), and cardamom (Elettaria cardamomum).
The plant is formally classified as Kaempferia parviflora Wall. ex Baker (also referred to as Black galingale, Thai black ginger, and Thai ginseng), belonging to the family Zingiberaceae, genus Kaempferia.
Common names in English include: black galingale, black ginger, Thai black ginger, Thai ginseng, and black galangal. In Thai, it is known locally as krachaidam, krachaidam hoi, and krachai dum, and it is indigenous not only to Thailand but also to Cambodia, Burma/Myanmar, and Laos.
It is a dark purple, stemless rhizome that belongs to the Zingiberaceae family with historical medicinal benefits. The flesh within the tubers may appear dull purple or black, and the leaves are single, alternate, 7–15 cm wide and 30–35 cm long, piercing upward from the underground rhizome. The flowers are pale pink.
Black ginger, the rhizome of Kaempferia parviflora, has traditionally been used as food and folk medicine for more than 1,000 years in Thailand. Dried rhizomes are generally pulverized and used as tea bags, whereas fresh rhizomes are utilized to brew wine.
The wine preparation is increasingly used in Thailand as a tonic and as an aphrodisiac. As dietary supplements, it has been made into various preparations such as medicinal liquor or liquor plus honey, pills (powdered rhizome with honey), capsules, and tablets.
Black ginger has traditionally been used as food and a folk medicine for more than 1,000 years in Thailand. It is one of the most popular herbs in Thailand, having been used in folk medicine and food for more than 100 years by documented record, with far deeper traditional roots.
In Thai traditional medicine, the rhizome of Kaempferia parviflora, known locally as Krachaidum, has been utilized for centuries to treat a variety of ailments through decoctions prepared by boiling the rhizome. These preparations are commonly employed to alleviate allergies, asthma, gout, diarrhea, peptic ulcers, and colic, reflecting its role as a versatile remedy in folk healing practices.
In Thai traditional medicine, black ginger has been claimed to cure allergy, asthma, impotence, gout, diarrhea, dysentery, peptic ulcer, and diabetes.
Reputed for its aphrodisiac effect, rhizomes of Kaempferia parviflora have been used as traditional medicine for various medicinal purposes, including as a tonic for rectifying male erectile dysfunction. In traditional medicine, rhizomes are brought to boil or soaked with alcohol and used to drink as an elixir to improve sexual performance.
It has been long used in Thai traditional medicine for treating various ailments including allergy, fatigue, sexual dysfunction, and ulcer. In addition, it is also used as a longevity-promoting substance and as a nerve tonic.
In Thai culture, Kaempferia parviflora, known locally as krachai dam, symbolizes vitality and empowerment within folklore and traditional practices. It is incorporated into socio-religious rituals as one of the "Wan" plants, believed to provide protection, prosperity, and charm while warding off misfortune and enhancing personal strength. Additionally, it features among the revered "Wan 108 species" used to create sacred objects, underscoring its symbolic association with resilience and awe-inspiring energy in regional lore.
In traditional use, it is employed in teas, infusions, ointments, and wines to treat an array of health issues such as inflammation, ulcers, gout, colic disorders, abscesses, allergies, and osteoarthritis.
Traditionally regarded as an "elixir of life," K. parviflora is believed to possess anti-fatigue, aphrodisiac, and longevity-promoting effects.
Black ginger extract (K. parviflora extracts: KPE) is rich in polymethoxy flavonoids (PMF), which exhibit various bioactivities. Analysis of the bioactive compounds in black ginger showed that there are more than 140 ingredients in Kaempferia parviflora. The major bioactive compounds are methoxyflavones, which have been investigated for their anti-obesity, anti-diabetes, physical performance, and aphrodisiac properties.
Phytochemical investigations of K. parviflora extract showed flavones as the major compound in the crude extract, with multiple methoxy functional groups in their chemical structure known as polymethoxyflavones (PMFs). To date, 15 PMFs with methoxy-group substitutions varying from 1 to 5 have been discovered.
The three major PMF marker compounds most commonly used for standardization of extracts are:
Phytochemical analysis aided by liquid chromatography–mass spectrometry (LC-MS) from the n-hexane fraction of the methanolic extract of K. parviflora rhizomes has led to the isolation of compounds including 3,7-dimethoxy-5-hydroxyflavone, 5-hydroxy-7-methoxyflavone, 7,4′-dimethylapigenin, 3,5,7-trimethoxyflavone, 3,7,4′-trimethylkaempferol, and 5-hydroxy-3,7,3′,4′-tetramethoxyflavone, among others.
The KP rhizome contains numerous active constituents, including alkaloids, glycosides, flavonoids, phenols, polyphenols, lipophenols, saponins, tannins, terpenes, and steroid components.
Pharmacological studies have identified multiple mechanisms, including cellular metabolism-regulating activity, anticancer activity, vascular relaxation and cardioprotective activity, sexual-enhancing activity, neuroprotective activity, antiallergic, anti-inflammatory, and antioxidative activity, antiosteoarthritis activity, antimicroorganism activity, and transdermal-permeable activity. These are thought to be associated with increased mitochondrial functions and an activated cGMP-NO signaling pathway. However, the underlying molecular mechanisms of KP and its methoxyflavones are still under investigation.
PDE5 Inhibition (Sexual Function): The main chemical compound, 5,7-dimethoxyflavone — a flavonoid substance — has been reported to possess potential as a PDE5 inhibitor. By inhibiting PDE5, the enzyme that selectively degrades cGMP supplying the corpus cavernosum of the penis, the herb acts to enhance sexual performance by increasing blood flow to the testis and stimulating dopaminergic functions in the hypothalamus linked to erection.
Anti-inflammatory Pathways: Methoxyflavones have been found to inhibit the generation of nitric oxide (NO), inducible nitric oxide synthase (iNOS), prostaglandin E₂ (PGE₂), and TNF-α via activation of the spleen tyrosine kinase (SYK) pathway, but not the ERK or c-Jun N-terminal kinase (JNK) pathways, in LPS-induced RAW264.7 cells.
Anti-obesity and Metabolic Pathways: Searching for active ingredients in KPE revealed that it contains at least 12 kinds of polymethoxyflavonoid. KPE and its component PMFs show an inhibitory effect on pancreatic lipase, suggesting that KPE has a preventive effect on obesity and various metabolic diseases through this mechanism. Furthermore, treatment with KPE and PMFs fractions significantly suppressed peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), and various adipogenic metabolic factors in human mesenchymal stem cells.
Bioavailability Limitation: The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability. The PMFs have a high lipophilic character and low water solubility, which is a recognized challenge in formulation development.
This is the area with the most human clinical evidence, though the total number of studies remains small.
Elderly Volunteers — Grip Strength and Oxidative Status (RCT, 2012): A total of 45 healthy elderly volunteers were recruited to take part in a randomized trial designed to investigate the effects of 8-week consumption of K. parviflora on health-related physical fitness. Subjects were older than 60 years, healthy, and without history of cardiovascular, respiratory, or neuropsychological diseases, head injury, diabetes, or cancer. Each capsule contained a specialized rhizome extract containing 5,7-dimethoxyflavone (2.1%), 5,7,4′-trimethoxyflavone (3.1%), and 3,5,7,3′,4′-pentamethoxyflavone (2.3%), administered at doses of 25 mg and 90 mg per day. The 2016 systematic review of clinical evidence for K. parviflora identified 7 included studies from 683 records. From current clinical trials, Krachaidum showed positive benefits but results remained inconclusive since small studies were included. Results found that Krachaidum significantly increased hand grip strength and enhanced sexual erotic stimuli, but these were based on only 2 studies and 1 study, respectively.
Soccer Players — Muscle Strength and Aerobic Capacity (RCT, 2015): Sixty soccer players who routinely trained at a sports school participated in a double-blind, placebo-controlled trial and were randomly allocated to the treatment group or placebo group. Participants received either 180 mg of Kaempferia parviflora extract in capsules or a placebo once daily for 12 weeks. The investigators concluded that the use of Kaempferia parviflora as a food supplement has the potential to enhance muscle strength and may improve aerobic capacity, both of which are important components of physical fitness in soccer players.
Preclinical evidence for physical performance: Physical fitness performance and muscular endurance were superior in mice orally administered KPE (45 mg/kg/day) for 4 weeks than in control mice. Moreover, KPE enhanced physical fitness, namely grip strength, leg muscle strength, balance, endurance, and locomotor activity in athletes, the elderly, and healthy individuals.
Acute Exercise — Null Finding: An earlier study found that acute dosing did not have an effect on sprint and endurance exercise in humans, but indicated that chronic effects or actions in other populations cannot be excluded. This suggests that any physical performance benefits may require chronic supplementation rather than acute use.
Overall evidence strength: Preliminary to moderate. A small number of randomized, double-blind, placebo-controlled trials in humans (soccer players and elderly volunteers) show positive effects on grip strength and muscle strength, but study populations are small, and a systematic review characterized the overall evidence as inconclusive.
Elderly Men — Erotic Stimulus Response (clinical study): In one study, 15 elderly male volunteers with a mean age of 65 years received 90 mg of a K. parviflora extract per day and exhibited statistically significant decreases in response latency to erotic visual stimuli. Participants also showed increased flaccid and erect penile size.
Healthy Elderly Men — Oxidative Stress and Response (RCT): In another human study, 45 healthy elderly volunteers were randomized to receive a placebo or K. parviflora extract (25 mg or 90 mg) once daily for eight weeks. The result showed that supplementation decreased oxidative stress. The 90 mg/day dose was associated with quicker erectile response time to visual erotic stimuli compared with placebo.
Open-Label Pilot Study — IIEF Scores (2017–2018): A total of 13 subjects completed a 30-day trial. The Day 30 analysis showed a statistically significant mean increase in scores attained on the IIEF questionnaire related to total score, erectile function domain, intercourse satisfaction domain, and orgasmic function domain. For the Global Assessment Question, 61.5% of subjects noted the product improved their erections. Results point toward the need for additional controlled studies with larger sample sizes.
Meta-analytic summary: A 2023 systematic review and meta-analysis confirmed that Kaempferia parviflora extracts markedly improved sexual function in animals and improved physical performance in both animals and humans. However, the evidence base remains limited by small sample sizes and the lack of large-scale placebo-controlled trials specifically powered for sexual outcomes.
Overall evidence strength: Preliminary. Human evidence consists of small studies, including one open-label uncontrolled pilot and two randomized studies with modest sample sizes. No large-scale, adequately powered RCT has confirmed efficacy for erectile dysfunction to date.
Japanese Overweight Adults — Visceral Fat (RCT, 2021): A randomized, double-blind, placebo-controlled parallel-group study conducted in Japanese overweight adults investigated the effects of polymethoxyflavone purified from Kaempferia parviflora on visceral fat. A total of 80 subjects (aged 20–64 years, 23.0 ≤ BMI < 30 kg/m²) were randomly assigned in a 1:1 ratio to active or placebo groups. Over a 12-week period, each subject received two capsules containing 12 mg of polymethoxyflavone purified from K. parviflora per day or placebo. The primary outcome was reduction in visceral fat area (VFA), while secondary outcomes included subcutaneous fat area (SFA) and total fat area (TFA). A significant reduction was observed in SFA and TFA after 8 and 12 weeks in the active group; TFA was significantly lower than in the placebo group at 8 and 12 weeks. No adverse events associated with the test supplements were observed. The study concluded that administration of polymethoxyflavone purified from K. parviflora reduces visceral fat in Japanese overweight adults.
Preclinical (animal) evidence: To clarify the molecular mechanisms and active ingredients of K. parviflora with anti-obesity effect, researchers investigated the effect of ethyl acetate extract (KPE) on TSOD mice (a spontaneously obese Type II diabetes model). In the TSOD groups, KPE showed a suppressive effect on body weight increase and visceral fat accumulation and also showed preventive effects on symptoms related to insulin resistance, hypertension, and fatty liver.
Overall evidence strength: One reasonably sized, properly designed RCT in humans supports a fat-reduction effect. Preclinical data are consistent, but confirmatory human trials are needed to establish the clinical benefit fully.
Kaempferia parviflora (KP) has been used in traditional Thai medicine to cure gastrointestinal disorders since ancient times, and laboratory research has investigated its anti-inflammatory mechanisms. Molecular docking analyses reveal that key methoxyflavones interact with pivotal proteins such as protein kinase B (AKT1), proto-oncogene tyrosine-protein kinase (SRC), and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1), suggesting their potential involvement in modulating inflammation. Experimental results confirmed that 5,7,4′-trimethoxyflavone and 3,5,7-trimethoxyflavone significantly inhibited keratinocyte proliferation, migration, and macrophage activation.
Overall evidence strength: Predominantly in vitro and animal-based. No published large-scale human clinical trials have specifically tested anti-inflammatory outcomes in inflammatory disease populations.
Effects such as antioxidant, antidiabetic, cardiovascular, skin health, urology, and immunomodulation have shown positive findings in preclinical studies only, at both in vivo and in vitro levels, thus needing further validation in clinical studies.
A clinical pharmacokinetic and glucose tolerance study in healthy subjects was conducted to assess the safety of KP extract and the pharmacokinetics of its methoxyflavones. This is the first demonstration of the pharmacokinetic parameters of methoxyflavones of KP extract in healthy volunteers. The data suggest the safety of the KP extract and will be of benefit for further clinical trials using KP extract as food and sport supplements as well as a drug in health product development.
Overall evidence strength: Preclinical (in vitro and animal). Human clinical evidence for antidiabetic effects specifically is limited to pharmacokinetic characterization in healthy volunteers.
K. parviflora shows conflicting findings in neuropsychiatry applications: an in vivo animal study demonstrated its ability to ameliorate cognitive impairments, while no significant effect was observed in healthy adults in terms of changes in physical or psychological stress.
Overall evidence strength: Weak and conflicting. Animal studies are positive for some cognitive endpoints, but available human data do not show significant neuropsychiatric benefit in healthy individuals.
Research demonstrates that polymethoxyflavones purified from K. parviflora rhizomes (5,7-dimethoxyflavone, 5,7,4′-trimethoxyflavone, and 3,5,7,3′,4′-pentamethoxyflavone) suppressed cellular senescence, reactive oxygen species, and the senescence-associated secretory phenotype in primary human dermal fibroblasts. In addition, they increased tropocollagen synthesis and alleviated free radical-induced cellular and mitochondrial damage. Moreover, the compounds mitigated chronological aging in a human ex vivo skin model by attenuating senescence and restoring expression of essential components of the extracellular matrix, including collagen type I, fibrillin-1, and hyaluronic acid.
Overall evidence strength: Preclinical (in vitro and ex vivo human skin model). No published controlled clinical trials in living human subjects for skin aging endpoints are available in the peer-reviewed literature.
A few effects of K. parviflora were only demonstrated at the in vitro stage, including anticancer, antimicrobial, hepatoprotective effects, and potential benefits in ophthalmological diseases. The PMFs in crude extract demonstrate numerous biological activities including anticancer, antidiabetic, antioxidant, and antimicrobial activities, despite their high lipophilic character and low water solubility.
Overall evidence strength: In vitro only. No human clinical evidence has been published for these applications.
The following dosages are reported as used in the identified peer-reviewed studies and should not be construed as established therapeutic recommendations:
A toxicological evaluation examined the safety profile of a standardized hydroalcoholic KP rhizome extract via mutagenicity and sub-chronic toxicity evaluations in vitro and in vivo. In vitro mutagenicity was assessed via reverse mutation tests using multiple strains of Salmonella typhimurium and Escherichia coli WP2 uvrA.
These results demonstrate that KP extract is not genotoxic and that 90-day oral administration of the doses tested did not result in toxicity. Therefore, KP extract has a high safety margin for daily use. The no-observed-adverse-effect-level (NOAEL) of the extract was > 249 mg/kg.
Sub-chronic administration of KP extract increased platelet levels in animals administered low-dose KP extract (25 mg/kg bw/day). However, hematological and biochemical parameters remained within normal physiological ranges for the animal species. No toxicological changes were observed in macroscopic and histopathological analyses. These results demonstrate that KP extract is not genotoxic and that 90-day oral administration of the doses tested did not result in toxicity.
A previous study examining daily administration of KP extract for 6 months in rats reported no toxicological effects. Other studies reported that daily intake of KP extract for 12 weeks had no adverse effects on blood chemistry parameters.
A randomized double-blind placebo-controlled safety study enrolled 52 healthy Japanese subjects; each subject received five KPE tablets (containing 150 mg of KPFORCE™ per tablet) or placebo daily for 4 weeks. There were no adverse events related to KPE intake or any abnormalities compared with the placebo group in anthropometric, cardiovascular, blood, and urine parameters during the course of the study. Thus, daily KPE ingestion was found to be safe in healthy Japanese men and women.
With regard to harmful effects, a systematic review found no adverse events reported even when Krachaidum was used at 1.35 g/day. Therefore, future studies are needed with regards to both safety and efficacy outcomes.
The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability. A solid self-microemulsifying drug delivery system (SMEDDS) has been developed to address limitations such as poor water solubility and low bioavailability. This is an active area of pharmaceutical research for improving the delivery of PMF-based preparations.
Clinical studies for K. parviflora are limited. Key bioactive compounds, particularly polymethoxy flavones, have demonstrated a range of biological activities including anti-inflammatory, anti-obesity, and antidiabetic effects, with evidence from animal and clinical trials. The findings support black ginger as a functional food material requiring further clinical trials for validation.
The underlying molecular mechanisms of KP and its methoxyflavones are still under investigation. The clinical applications of KP and its methoxyflavones may be limited due to their low bioavailability.
A perspective review of current evidence shows that K. parviflora is a plant with potential for 16 different diseases and various pharmacological applications, with the rhizome most popularly used traditionally and investigated, and PMF as the most studied bioactive phytoconstituent.
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