What is Bokbunja?

Bokbunja is the fruit of the Korean black raspberry, Rubus coreanus. The berries are dried for tea, pressed for juice or vinegar, or soaked in spirit to make a sweet red wine. People take it as a daily tonic, most often for low energy and for men's sexual health.

Korean medicine has used this berry for hundreds of years. Old texts call it a kidney tonic. In that system the kidney is tied to energy, aging and sex drive, which is not the same as the kidney your doctor scans.

The evidence in people is thin. Almost all of the research is lab and animal work. Long tradition is not proof of effect, so no one can say this berry treats any illness.

As a food, the ripe berry is safe for most adults. The wine form is a real alcoholic drink, and that is where most of the risk sits.

How does Bokbunja work?

The honest answer is that no one has shown how bokbunja works in the human body.

The berry is full of plant chemicals called polyphenols. In test tubes these soak up free radicals, which are unstable waste molecules that can damage cells. Animal studies have looked at blood sugar, blood fats and hormones, with mixed results.

A test tube is not a person. Much of what you eat is broken down in the gut and never reaches the blood in the same form. So treat every idea about how it works as untested.

What forms does Bokbunja come in?

Bokbunja comes in a few everyday forms. The wine is the best known one outside Korea.

Dried whole berries are simmered to make a tea. Juice and vinegar drinks are sold in bottles and mixed with water. Powders and capsules from the dried fruit are sold as supplements.

Bokbunja ju is the sweet red wine, usually about 12 to 19 percent alcohol. Treat it as a drink, not as a medicine. Jams, syrups and frozen berries are simply food.

Where it comes from:

Bokbunja has been used in Korea for centuries and appears in classic Korean medical texts as a kidney tonic.

The name comes from a folk tale. It is said a man who ate the berries passed urine with such force that he tipped over the chamber pot. Today the fruit is farmed heavily in Gochang, in the south-west, and the wine is a regional specialty.

What does Bokbunja help with?

• Low energy and tiredness (traditional use): This is the main traditional reason Korean practitioners give bokbunja. It is served as a warming daily tonic, often as tea or wine. No human trial shows it lifts energy, and tiredness has many causes that need a doctor, such as low iron or a thyroid problem.
• Male sexual health and low sex drive (traditional use): Bokbunja has a long folk name as a men's tonic, and the chamber pot story is part of that reputation. Animal studies have looked at sperm counts and hormones. There is no solid human trial to support it, and ongoing trouble with erections can be an early sign of heart or blood vessel disease, so see a doctor.
• Frequent or night-time urination (traditional use): Korean texts use the unripe dried berry for people who pass urine often or wet the bed. This is tradition only. New or worsening urinary changes need checking, since they may point to an infection, diabetes or a prostate problem.
• General antioxidant support (lab work only): The berry scores well on lab tests that measure how fast a substance mops up free radicals. Those tests happen in a dish, not in a body. A high lab score has never been shown to mean better health for the person eating the fruit.
• Blood sugar and blood fat support (animal work only): Rat and mouse studies have reported small changes in blood sugar and cholesterol. These results have not been repeated in people in any trial we can point to. Do not use bokbunja in place of diabetes or cholesterol medicine.

Which foods are rich in Bokbunja?

1. Fresh or frozen bokbunja berries: the whole fruit, with fibre and vitamin C
2. Bokbunja tea from dried berries: no alcohol and no added sugar
3. Bokbunja vinegar drink: tart, usually watered down before drinking
4. Bokbunja jam and syrup: tasty, but high in sugar
5. Bokbunja ju wine: the traditional form, and an alcoholic drink
6. Other raspberries and blackberries: close cousins with similar purple pigments

Practical Tips:

The whole berry and the plain tea are the gentlest ways to try it.

What are the side effects of Bokbunja?

• Upset stomach or loose stools, mostly from large amounts
• Heartburn from the vinegar or juice drinks, which are acidic
• Tooth enamel wear if you sip acidic bokbunja vinegar often
• Blood sugar spikes from sweetened wine, juice and syrup
• Hangover, flushing and poor sleep from the wine
• Allergic reaction in people allergic to berries, with itching, rash or swelling

Good to know:

Side effects from the plain fruit are mild and uncommon. It is a food, and most people eat it without trouble.

Most real problems come from the two sweet forms. The wine brings every risk that alcohol brings, and the syrups and juices carry a lot of sugar.

Stop and get medical advice if you get a rash, swelling or trouble breathing after taking it.

How much Bokbunja should you take?

• Recommended daily: There is no proven dose, because the human studies needed to set one have not been done. As a food, a normal serving of berries, juice or jam is fine for most adults. For tea, Korean practice uses roughly 5 to 15 grams of dried fruit simmered in water. For capsules and powders, follow the label and do not exceed it. For bokbunja wine, count it as alcohol. Standard advice is no more than one to two small glasses in a day, with alcohol-free days each week.
• Best time of day: Any time of day suits the tea, juice or berries. Many people in Korea drink the tea in the morning or early evening. Keep the wine to mealtimes, and skip it close to bedtime, since alcohol breaks up your sleep.
• With or without food: Food is the easier choice. The berries and the vinegar drink are acidic and can sting an empty stomach. Never drink bokbunja wine on an empty stomach, as the alcohol hits you harder.
• Time to effect: Nothing reliable is known, because the human trials have not been done. Any tonic effect people report tends to be described over weeks, not hours. If you notice a fast, strong effect, look at the alcohol in the wine first.
• How long to take it: As a food, you can eat the berries as long as you like. If you are taking capsules or strong daily tea for a health reason, give it about four to six weeks and then stop to think. If nothing has changed, there is no reason to keep buying it. Check in with a doctor if the problem you are treating is still there after a month.