Educational information, not medical advice — ask your doctor or midwife.
Track Renjuin with reminders and record whether it helped, in the app.
Renjuin is a herbal formula from Kampo, the traditional medicine of Japan. Its name means "string-of-pearls drink". It is given for dizziness, lightheadedness and a fluttering heartbeat.
Renjuin joins two older formulas. One is ryokeijutsukanto, long used for dizziness and palpitations. The other is shimotsuto, long used for pallor, tiredness and period problems.
It is a ministry-approved Kampo formula in Japan. In practice a Kampo doctor chooses it for a person, not for a disease name alone.
Here is the plain verdict. Renjuin has a long record in Japan, but we found no controlled human trials of the formula. Traditional use is not proof that a remedy works.
Safety, not benefit, is the main point of this page. Renjuin contains kanzo (licorice), and licorice has real, documented risks in people.
Kampo explains Renjuin in its own terms. It is said to move stagnant "water" and to build "blood". These are traditional ideas, not measured body chemistry.
Modern mechanism work on the whole formula is sparse. We found no studies that test how Renjuin as a blend acts in the human body.
One part is well understood. Glycyrrhizin, from kanzo (licorice), blocks an enzyme in the kidney. In people this leads the body to hold salt and water and to lose potassium.
Doctors call that pattern pseudoaldosteronism (a false hormone-like state that holds salt and drops potassium). This is a proven human effect, not a lab-only finding.
The other herbs have been looked at mainly in test tubes and animals. Peony and cnidium extracts appear to relax blood vessels in animal work. Whether that happens in people taking Renjuin is not known.
Most people meet Renjuin as a granulated extract in sachets. Licensed Japanese makers supply it as an approved Kampo product. We could not confirm a specific maker's product number, so none is given here.
It also exists as a fine powder, as tablets, and as a decoction (herbs boiled in water). The decoction is the older form and is still used by some practitioners.
Supply outside Japan is patchy. Imported products vary in strength and in how much licorice they contain.
Renjuin is a Japanese formula built from two Chinese classics. Ryokeijutsukanto comes from the Han-era Shang Han Lun. Shimotsuto comes from a Song-era formulary.
Japanese doctors combined the two during the Edo period. The joined formula was used for dizzy, pale, easily tired patients.
It stayed in use and is now an approved Kampo formula in Japan's health system.
Some reactions to Renjuin need urgent care. Call your local emergency number or go to an emergency department straight away — do not wait to see whether it passes.
Get medical help the same day if your ankles or face swell, if you gain weight fast, or if your muscles feel weak or cramp.
Go to an emergency department if your urine turns dark or cola-coloured, if your heart pounds or skips, or if you faint.
See a doctor promptly for yellow skin or eyes, or for a new dry cough with fever and breathlessness.
See a doctor before you start if your dizziness is new, severe, or comes with chest pain, slurred speech or a bad headache.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Renjuin is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
One email with the summary. We'll also send a short weekly evidence update — unsubscribe any time.
