Kaempferia Parviflora
Kaempferia parviflora (Black Ginger / Krachai Dam), Thai 'Eastern Viagra'
Evidence grade 3 of 5, Mixed. Read how the Atlas grades evidence.
The written rationale for this grade is still being prepared.
- FDA
- Not FDA approved; sold as a dietary supplement / functional food ingredient
Reference only. Not medical advice.
What can go wrong
Short-term human safety in trials appears acceptable, with mild GI effects reported. Long-term safety, drug interactions (including additive effects if combined with PDE5 inhibitors or nitrates given the vasodilatory mechanism), and effects in men with cardiovascular disease are not well characterized. As with other 'natural PDE5' botanicals, undeclared PDE5-drug adulteration is a category risk to watch.
This is something to take to a clinician. The Atlas can tell you what is known about kaempferia parviflora in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.
Kaempferia parviflora (black ginger, krachai dam) is a Thai rhizome rich in polymethoxyflavones, marketed for erectile function, physical performance, and metabolic health. A small randomized trial in healthy men found 90 mg/day reduced response time to erotic visual stimuli and increased penile dimensions versus placebo, without changing testosterone, LH, or FSH, pointing to a vasodilatory/nitric-oxide mechanism rather than a hormonal one. Other pilot and animal-plus-human meta-analytic work supports effects on ED and physical performance, though trials are small and often industry-linked.
A Thai rhizome with a real small erectile trial, whose effect looks vascular, not hormonal.
What people take it for
These are the reasons people give for taking it. They are not effects it has been shown to have.
How it is supposed to work
Polymethoxyflavones (e.g., 5,7-dimethoxyflavone) show PDE5-inhibitory and vasorelaxant activity in preclinical models and may enhance nitric-oxide-mediated blood flow and mitochondrial/energy metabolism. Consistent with this, human trials show sexual and performance effects without changes in gonadotropins or testosterone, i.e., a vascular/metabolic rather than androgenic route.
Vascular, not hormonal, and the trials are small
Marketed under a 'testosterone/vitality' halo, but the human hormone data show no change in T, LH, or FSH, so any benefit is blood-flow-mediated rather than androgenic. The supportive trials are small, several are linked to ingredient suppliers, and effect sizes for things like penile dimension change should be read cautiously given sample sizes and measurement subjectivity.
What people get wrong
Often saidBlack ginger boosts testosterone
ActuallyHuman trials show no change in testosterone, LH, or FSH; the effect appears vascular, not hormonal.
Often saidIt is as effective as Viagra
ActuallyMarketing calls it 'Eastern Viagra,' but the human trials are small and it has not been compared head-to-head against an adequate PDE5-inhibitor dose.
Who profits, and who pushes back
Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.
Set against the alternatives
Among 'natural PDE5' botanicals, Kaempferia parviflora has better (though still small) human RCT data than Butea superba, and its blood-flow mechanism is more coherent than testosterone-boosting botanicals. It remains far less established than prescription PDE5 inhibitors.
What we do not know
- Do larger independent trials confirm the erectile and performance effects?
- How does it compare head-to-head with a proper PDE5-inhibitor dose?
- What are the long-term and cardiovascular safety data?
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Potency depends on methoxyflavone content, which varies by cultivar, extraction, and standardization; branded standardized extracts differ substantially from crude rhizome powder. Species and adulteration authentication (including screening for spiked PDE5 drugs) are prudent given the 'natural Viagra' positioning.
At a glance
- Common names
- Black ginger, krachai dam
- Erectile trial dose
- 90 mg/day (methoxyflavone extract)
- Mechanism signal
- Blood flow / NO, not testosterone (T, LH, FSH unchanged)
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Kaempferia Parviflora. A short entry is not a safe entry.
- Timeline. We have not built the dated record of research and regulatory events.
- Cost and market. We have not documented what it sells for or who sells it.
- Supply chain. We have not mapped where it is made.
- Who uses it. We have not documented the user groups.
- What could change. No forward-looking summary yet.
- Children and teenagers. We have not checked what is known about younger people.
- Where we land. We have not taken a position on this yet.
Sources
The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.
The studies that matter
Randomized trial in healthy men (90 mg/day)2010s
Reduced response time to erotic stimuli and increased penile dimensions vs placebo; no change in T, LH, FSH
Wattanapitayakul / Saokaew pilot, self-assessed sexual health2018
Ethanol extract improved self-reported sexual health in a small pilot
Systematic review/meta-analysis (animal + human)2023
Beneficial effects reported for metabolic syndrome and erectile dysfunction; evidence limited by trial size/quality