Mung Bean in Beauty

Mung bean (nokdu, 녹두) is a pantry staple. The Encyclopedia of Korean Culture describes it as a drought-tolerant crop that suits Korea's dry harvest season, with a seed that is roughly half starch. That starch gives Korean its word for starch, nokmal, and it becomes jelly (cheongpomuk), noodles and the batter of nokdu bindaetteok. Sprouted, the bean becomes the sukju of sukju-namul. For the bean as food, see nokdu.

Jodu: a bean powder for washing

Before soap bars arrived, many households washed with ground beans. The Encyclopedia of Korean Culture entry on face washing (sesu) describes jodu (澡豆) as a forerunner of soap made from red bean and mung bean powder. Ordinary households used it, alongside lye water or the water from boiling soybean hulls, to clear away grime and, it says, to whiten the skin. A Korea Times feature on Joseon-era skincare describes the cleanser as a fine powder of mung beans, adzuki beans and soybeans, milled, dehulled, ground again and sifted. It cites a Joseon text for its power to remove dead skin and leave the face softer and paler. The bean smell was a drawback, and the same article says a perfumed version became a luxury gift among court women. The encyclopedia's soap entry adds that imported soap, arriving after Korea opened its ports, pushed jodu and lye out of use.

Two cautions. The entries I read give no start date for jodu, so claims that it goes back to a particular dynasty are left out here. And the Korea Times article says the Donguibogam credits mung bean powder with keeping skin healthy and treating skin eruptions; the encyclopedia's mung bean entry likewise says the bean was thought to detoxify and was used on boils. Read both as what old texts believed, not as tested treatments. For the wider setting see Joseon cosmetics and hanbang beauty, and for another pantry cleanser, rice water.

What a bean powder does on skin

The plausible mechanism is mechanical. A dry powder rubbed on wet skin lifts oil and loose surface cells by gentle friction, and a starchy bean makes a mild paste. That is reasoning, not a measured result from a study on jodu. The American Academy of Dermatology notes that physical scrubs can be too irritating for dry, sensitive or acne-prone skin, which applies to any gritty powder.

What the research shows

I found no human trial of mung bean used on skin. What exists is laboratory work. A 2026 paper in Antioxidants tested extracts of mung bean seed coat, a by-product of noodle making, entirely in cells and test tubes. In a cultured human keratinocyte line stressed with high glucose, the ethanol extract lowered reactive oxygen species, sped up closure of a scratch wound and shifted the expression of several genes tied to antioxidant defense and inflammation. The authors point out that the work was in vitro only, that toxicity was not tested, and that the findings rest on gene-expression data rather than protein measurements. A cell result like this is a lead for researchers, not evidence that a mung bean paste improves anyone's skin.

Evidence status

• Traditional use: well documented for jodu as a washing powder (Encyclopedia of Korean Culture, Korea Times). A start date is not given in the entries consulted.
• Old medical belief: mung bean for skin eruptions is recorded in old texts; no modern test was found.
• Modern evidence: one cell-culture study of seed-coat extract; no human skin trial found.
• Practical note: mung bean is a legume, so anyone with a legume allergy should skip bean powders and patch-test first. Do not scrub broken, sunburned or inflamed skin.