Buyer Beware: Red Yeast Rice Supplements Linked to Deaths, Hospitalizations


Japan’s health ministry has issued a warning to consumers regarding red yeast rice dietary supplements containing a red species of mold after 5 people died and more were hospitalized after consumption.

Last month, supplements containing beni koji were pulled off the shelves in Japan after reports came out that they were linked to deaths and hospitalizations. Although the exact reason why remains unknown, health officials are warning consumers everywhere to be wary of supplements containing the ingredient, especially as the supplements were exported to other countries and don’t require a prescription to purchase.

Red yeast rice supplement on wooden spoon / MilletStudio -

Red yeast rice supplement on wooden spoon / MilletStudio -

What's the Issue?

In March, Osaka-based Kobayashi Pharmaceutical Co. faced criticism for its delayed response to a health scare. The company finally announced that 5 people had died and over 100 were hospitalized after taking its cholesterol-lowering supplements containing beni koji, a red species of mold.1 Reports revealed that Kobayashi Pharmaceutical was aware of potential health risks as early as January, raising concerns about the company’s handling of the situation and prompting facility inspections by the Japanese health ministry.2 The supplements were recalled, along with dozens of other products such as miso paste, crackers, and a vinegar dressing that also contained the red mold derivative.3

Kobayashi Pharmaceutical is well established in the beni koji market; in the last 3 fiscal years, the company produced over a million packages of beni koji-containing products.3 But in a news conference earlier this month, company officials said they had found puberulic acid—a chemical compound that may be linked to the fatalities—in its products, which led to the supplements’ pull off the shelves.1 Notably, many people who died or were hospitalized experienced kidney complications. However, the company said it “cannot rule out” the unintended ingredient that had caused an adverse effect when combined with other ingredients.4

The company also revealed that it had exported its products to other countries, including China and Taiwan.1 While no US products have been recalled yet, consumers everywhere should be cautious of supplements containing beni koji.

Why it Matters

Many consumers assume that like OTC or prescription drugs, dietary supplements are vetted by the FDA. Contrary to this belief, dietary supplements lie outside of the FDA’s scope of verification.1 Rather, supplement manufacturers are the ones responsible for ensuring the safety and effectiveness of their products. Although federal law sets regulations for supplements, they are less strict compared to those for pharmaceuticals.

  • Over 20 years ago, red yeast rice supplements emerged as a more affordable option to prescription statins.1 But given the loose regulations surrounding dietary supplements, it can be hard to ascertain whether a red yeast rice supplement only contains what’s listed on the label, creating a “buyer beware” situation.
  • Yeast grown on rice produces various compounds, including lovastatin, which has cholesterol-lowering properties. However, if there’s a production error, rice can develop harmful agents, such as puberulic acid found in the recalled supplements, and citrinin, a chemical linked to kidney damage in animals.1
  • Japan’s health ministry warned that the death toll could increase if supplements were purchased or exported before the recall, particularly because these cholesterol-lowering products were sold without a prescription.3 This warning extends beyond Japan; regardless of location, consumers should be wary when purchasing dietary supplements containing beni koji online or in stores.

Expert Commentary

  • “I believe it is likely that this particular problem affects products outside Japan as well,” said David Light, president and co-founder of Valisure, an independent lab that tests drugs for impurities.1 Valisure is known for detecting carcinogens in products such as acne cream, sunscreen, and heartburn drug Zantec.
  • “Be skeptical,” said Amy Cadwallader, director for regulatory and public policy development at US Pharmacopeia.1 “If a claim on a label sounds too good to be true, it probably is.”
  • Those seeking help with lowering their cholesterol would be “better off going to a doctor and using a prescription cholesterol lower-er because there is more certainty as to what you’re getting,” according to Tod Cooperman, MD, president and founder of “Some of the older statins are generic now, so it’s probably less expensive and safer to be buying a generic statin at this point.”

In-Depth Insights

  • In 2022, tested red yeast rice supplements and found citrinin in 30% of the products tested. “One had 65 times the limit set in Europe,” said Cooperman.1
  • Although it is true that red yeast rice supplements can lower cholesterol, few supplements contain enough of the ingredient to be effective. Another analysis by found that only 2 of 10 products tested satisfied the threshold.1
  • The Japan Times reported earlier this week that kidney doctors nationwide received health complaints from 95 people who took Kobayashi Pharmaceutical’s beni koji supplements; in 75% of the 95 people, symptoms were alleviated after they stopped taking the pills.5
  • Akihiro Kobayashi, president of Kobayashi Pharmaceuticals, vowed to “investigate the full extent of this problem, but also prevent it from spreading, and provide explanations and compensation to those customers who have been affected.” The company has called upon several universities to conduct independent analyses of the issue.4

Extra Reading

READ MORE: Cardiology Resource Center

1. Gibson K. What US consumers should know about the health supplement linked to 5 deaths in Japan. CBS News. April 2, 2024. Accessed April 10, 2024.
2. Reuters. Japanese authorities inspect second Kobayashi Pharma factory after deaths. Reuters. April 1, 2024. Accessed April 10, 2024.
3. At least 5 deaths linked to recalled supplement pill containing red mold. News release. CBS News. March 29, 2024. Accessed April 10, 2024.
4. Semans H, Lau C. Japan recalls ‘red rice’ health products over suspected link to five deaths. CNN. March 29, 2024. Accessed April 10, 2024.
5. Otake T. Kidney doctors report 95 health complaints linked to beni koji pills. The Japan Times. April 9, 2024. Accessed April 10, 2024.
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