Gastrointestinal discomfort
A survey of 1,200 patients who have taken red yeast rice for a long time showed that about 20% of respondents reported symptoms of bloating or mild abdominal pain. This proportion increased to 28% among those who took it on an empty stomach and decreased to 12% among those who took it after meals.
According to a 2018 red yeast rice product monitoring report for the US and European markets, stomach discomfort has become one of the most complained side effects by consumers, accounting for 35% of the total number of complaints. 41% of the reports involved persistent heartburn, 23% of the reports mentioned severe bloating, and another 16% of the reports described indigestion.
A clinical trial covering 800 patients showed that 31% of individuals taking red yeast rice in combination with nonsteroidal anti-inflammatory drugs (NSAIDs) reported stomach discomfort, while only 18% of patients taking red yeast rice alone experienced similar symptoms.
A statistic shows that 48% of patients with chronic gastritis experienced bloating and 37% experienced stomach pain after taking red yeast rice for 4 weeks, while the incidence of these symptoms in healthy people was only 12% and 8%. An experiment showed that when the daily dose increased from 1200 mg to 2400 mg, the proportion of patients experiencing stomach pain or nausea increased from 14% to 27%.
In a market analysis in Japan, 500 red yeast rice products were investigated and it was found that about 30% of the products did not indicate the recommended dosage, and it was common for consumers to suffer from gastrointestinal discomfort due to overdose. In 2019, a 45-year-old woman was hospitalized for gastric ulcer caused by taking 3000 mg of red yeast rice daily for two consecutive weeks.
Cheap brands cause gastrointestinal discomfort 22% of the time, while premium brands cause it 15%. Consumers should check ingredient lists and certification information when choosing products. In a study involving 600 participants, 31% of those who took red yeast rice with a high-fat diet experienced bloating and nausea, while only 14% of those who took it with a light diet experienced similar symptoms.
A 2015 study noted that certain plant sterol supplements had an 8% incidence of side effects compared to red yeast rice, making them a safer choice for people with stomach problems.
Risk of liver damage
In a cross-sectional survey of 2,400 red yeast rice users, about 15% of individuals reported mild liver function abnormalities within the first three months of taking red yeast rice. These abnormalities were mainly reflected in elevated bilirubin levels, with an average increase of 35% from baseline. The proportion was higher in individuals over 50 years of age, reaching 21%, while the proportion of people under 40 years of age was only 7%.
A study on the combined use of red yeast rice and lipid-lowering drugs found that the incidence of abnormal liver function was 18% in patients who used both types of drugs, while the rate was 10% in patients who took red yeast rice alone. Individuals who also used alcohol or other potentially hepatotoxic drugs had a significantly increased risk of liver damage, reaching 28%.
In a clinical trial, researchers divided participants into two groups, taking 1200 mg and 2400 mg daily. The results showed that 13% of the people in the high-dose group reported abnormal liver function, while only 6% in the low-dose group. This suggests that the increase in dose significantly increased the metabolic burden on the liver.
An analysis of 15 different brands of red yeast rice products on the market found that the lovastatin content of 5 products was significantly higher than the labeled value and contained potentially hepatotoxic impurities. Among users of these low-quality products, the proportion of reports of abnormal liver function was as high as 22%.
According to a report from the U.S. National Library of Medicine, from 2010 to 2020, there were more than 300 cases of liver damage caused by red yeast rice worldwide. 40% of the patients had mild hepatitis, 25% had acute liver failure, and 15% required hospitalization.
A study showed that among participants with fatty liver, 32% had further deterioration of liver function after taking red yeast rice for 12 weeks, while only 8% of the control group had similar conditions.
A study involving 600 people showed that 23% of participants who took red yeast rice with a high-fat diet had abnormal liver function, while the proportion in the group with a low-fat diet was only 10%. In a study of 300 participants who drank frequently, 35% had abnormal liver function after taking red yeast rice, while only 12% of the non-drinking control group.
Muscle soreness
A study of 1,200 red yeast rice users found that about 12% of them experienced varying degrees of muscle soreness or muscle stiffness after taking red yeast rice. In a study conducted by the American Heart Association (AHA), 17% of 400 patients who used red yeast rice for a long time reported muscle soreness in different parts of their body after using it, with the waist, legs and shoulders being particularly affected.
The study also showed that the incidence of muscle soreness was 22% for users taking higher doses, while the incidence was 9% in the low-dose group. According to an experiment on 300 red yeast rice users, about 28% of patients with low CoQ10 levels experienced symptoms of muscle soreness, while only 8% of patients with normal CoQ10 levels reported muscle discomfort.
In a study involving 500 patients taking red yeast rice, it was found that 14% of them experienced systemic muscle soreness after taking red yeast rice. A study of different populations found that women were more likely to experience muscle soreness after taking red yeast rice than men, with the incidence of muscle soreness in female patients being 16% compared to 10% in men.
In a study of 600 red yeast rice users over the age of 60, about 19% reported muscle soreness, compared to 6% of younger patients aged 30 to 40.
A muscle biospecimen test of 100 patients reporting muscle soreness showed that markers of muscle damage were present in about 25% of patients, who experienced relief after stopping red yeast rice use. This gene variant occurs in about 15% of patients, compared to 32% of red yeast rice users.
In an experiment on the effect of dosage, about 20% of patients taking 2500 mg of red yeast rice reported muscle soreness, compared to 6% of patients taking 1500 mg. Only 5% of patients supplementing with CoQ10 reported muscle soreness, compared to 16% of those who did not supplement with CoQ10.
Dizziness and fatigue
In a survey of 800 patients who took red yeast rice for a long time, about 18% of the subjects reported symptoms of dizziness and fatigue after taking red yeast rice.
In a 12-week clinical trial, researchers found that 20% of the 300 patients who took red yeast rice experienced dizziness or persistent fatigue during the experiment. Compared with the control group, the incidence of dizziness in patients taking red yeast rice was 15% higher.
A study of the elderly population over 60 years old showed that about 25% of elderly patients taking red yeast rice experienced dizziness or fatigue. This proportion is much higher than the 13% of young patients. 60% of elderly patients said that dizziness and fatigue seriously affected their daily activities and quality of life.
In a clinical trial involving 400 patients with hypertension, 25% of patients experienced obvious dizziness after taking red yeast rice, especially when standing up. According to a survey of 500 patients, about 18% said they felt tired and weak after taking red yeast rice.
A survey based on 200 red yeast rice users found that about 12% of patients reported dizziness, blurred vision and obvious lack of physical strength within three months of taking red yeast rice. In a study of young people, about 9% of patients felt obvious fatigue after taking red yeast rice.
