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Limited evidenceGeneral health

Punarnava

An Ayurvedic herb (Boerhavia diffusa) used traditionally as a diuretic and kidney tonic. Essentially all of the published pharmacology is in cells and rodents; there are no controlled human trials of the single herb.

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What the science says

  • Diuretic and kidney-protective effects Limited evidence

    A comprehensive pharmacology review catalogues diuretic, nephroprotective and anti-inflammatory effects, but the underlying studies are cell-culture and rodent experiments. No randomised human trial has tested punarnava for kidney function or fluid retention.

  • Product identity is unreliable Limited evidence

    An HPLC fingerprinting survey of Boerhavia diffusa sold in Indian markets found substantial variation between samples, and the species is known to be substituted with look-alike plants. What is in the capsule may not be what is on the label.

Dosage & safety

Studied doseTraditional use is roughly 1–3 g/day of root powder, or 250–500 mg of extract on typical labels. No dose has been validated in humans.
SafetyHuman safety data are essentially absent. Because it is promoted as a diuretic, it should not be self-prescribed by anyone with kidney disease, heart failure or on diuretics, lithium or other drugs sensitive to fluid and electrolyte shifts. Avoid in pregnancy — traditional texts describe abortifacient use. Adulteration is a documented problem.

How to take it

TimingTraditionally taken twice daily; no evidence supports any particular timing.
With food?Take with food, since the root powder is bitter and can upset an empty stomach.
Worth knowingAdulteration of punarnava is documented, so buy from a supplier that does botanical identity testing rather than the cheapest bulk powder.

Interactions

With medications

  • diuretics

    Additive fluid and electrolyte loss. do not combine without medical supervision

  • lithium

    A diuretic action can reduce lithium clearance and raise blood levels into the toxic range. do not combine without lithium level monitoring

  • blood-pressure medication

    Possible additive lowering of blood pressure and fluid volume. monitor your blood pressure when you start

With other supplements

  • other diuretic herbs

    Additive fluid and electrolyte loss with no added benefit. use one at a time

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does punarnava help kidney function?

Unproven: punarnava's diuretic and kidney-protective effects come from cell and rodent studies, and no randomized human trial has tested it for kidney function or fluid retention. The evidence is limited.

Is punarnava safe for people with kidney disease?

No, punarnava should not be self-prescribed with kidney disease or heart failure, or alongside diuretics or lithium, because of its promoted diuretic action. Human safety data are essentially absent, and it should be avoided in pregnancy.

How much punarnava per day?

Traditional use of punarnava is roughly 1–3 g/day of root powder, or 250–500 mg of extract on typical labels, but no dose has been validated in humans. Buy from a supplier that does botanical identity testing, since adulteration is documented.

Scientific references

Related in General health

Herbal medicines: what the evidence says (335)