"I thought all the toxins had been flushed out of my body"... Experts reveal the truth about "detox foot baths"

"Detox Foot Baths" Gain Popularity on Social Media
Water Turns Black in Just 30 Minutes
No Basis for Claims They Can Assess Health
Experts: "It's Metal Oxidation, Not Toxins Leaving the Body"

So-called "detox foot baths," which claim to draw toxins out of the body simply by soaking one's feet in water, have recently gained popularity, particularly on social media. The sight of the water turning black after a foot bath has attracted attention, including from foreign tourists, but experts say the color change is caused by a chemical reaction unrelated to the removal of toxins from the body.

Water before the foot bath (left) and water that turned black an hour later (right). Yonhap News.

On October 15, Yonhap News reported on the controversy surrounding the "detox foot baths" recently trending on social media. Videos showing water turn brown or black after people soak their feet in salt water have recently been spreading online. The experience has become known as a "value-for-money detox" because it costs around 10,000 to 20,000 won for a session lasting 30 minutes to an hour.

Videos in English posted by some South Korean influencers have drawn comments from foreigners asking where the shops are or saying they would like to try the experience during a trip to South Korea. The businesses promote foot baths by highlighting patented technology or certifications and claiming that they can remove waste products from the body. Some shops also say the color of the water can indicate a person's health condition.

One owner of a foot bath specialist shop put an electrode device into salt water and claimed, "Hydrogen bubbles stimulate the soles of your feet, producing the same effect as exercising for two hours in just 30 minutes." When the water turned black, the owner asked customers whether they had cold hands and feet or were usually sensitive. Some businesses even display charts that identify areas of the body with potential problems based on the water's color. For example, orange is said to indicate an inflammatory reaction in the joints, while black supposedly represents toxins associated with the liver or heat.

As controversy grew, the companies said the change in water color was caused by a chemical reaction. The owner of one foot bath business explained that the color changed when salt water, metal and sweat reacted during electrolysis. The owner also clarified that the chart linking water colors to health conditions was not intended as a medical diagnosis, but was merely a reference based on folk remedies and meant to make the experience more enjoyable. YouTube screenshot

Experts, however, say there is no scientific basis for treating the change in water color after a foot bath as evidence that toxins have been removed from the body. Lee Deokhwan, an emeritus professor of chemistry at Sogang University, explained that foot bath machines work through electrolysis and that the reddish substances in the water are iron oxides. In simple terms, it is rusty water produced as metal corrodes.

He noted that salt is added to help electric current flow through the water, a process unrelated to drawing toxins out through the feet. Lee stressed that the skin acts as a barrier, preventing external substances from entering the body and substances inside it from escaping, and that the claim that toxins can be expelled through the skin simply by taking a foot bath is scientifically implausible.

Lee Kwangryeol, a professor of chemistry at Korea University, also suggested that metal components from the electrodes may have dissolved into the water. He said that waste products and harmful substances in the body are mainly processed and excreted through the functions of organs such as the liver and kidneys, and that claims that foot baths remove toxins lack sufficient evidence. He added that so-called "detox foot patches," which turn black when worn overnight, change color not because toxins are released from the feet but because moisture, such as sweat, reacts with the patch's ingredients.

As the controversy grew, the businesses said the change in water color was caused by a chemical reaction. The owner of one foot bath business explained that the color changed when salt water, metal and sweat reacted during electrolysis. The owner also clarified that the chart linking water colors to health conditions was not intended as a medical diagnosis, but was merely a reference based on folk remedies and meant to make the experience more enjoyable. Signs at some shops state that the color change results from a chemical reaction involving salt and metal filters, and that customers should consult a medical professional for an accurate health diagnosis.

A representative of another franchise also said its staff are taught that the color change is due to a chemical reaction, and that it is difficult to conclude that the change reflects waste products from the body. The concern is that customers may judge their health based solely on the water's color or mistakenly believe that toxins have actually been removed.

The Ministry of Food and Drug Safety said it is difficult to determine whether something is illegal based on a particular expression alone. However, if an advertisement as a whole gives the impression that it claims medical-device-level benefits, such as preventing or treating disease, it could constitute misleading advertising under the Medical Devices Act. If a violation is confirmed, measures such as a corrective order or a referral for prosecution may be taken, depending on the circumstances. Experts emphasize that while a foot bath may provide temporary relaxation and comfort through warm water, changes in the water's color cannot show whether toxins have been removed from the body or indicate a person's health condition.

This content was produced with the assistance of AI translation services.