Some red yeast rice supplements sold in U.S. stores don’t have any of the active ingredient (monacolin K) that’s supposed to help lower cholesterol, while others have wildly different amounts—from almost nothing to a lot—so you never know what you’re really getting.
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
definitive
Can make definitive causal claims
Assessment Explanation
The claim reports specific, measurable analytical results from a tested sample of commercial products. It does not infer causation or mechanism, but describes observed concentrations—this is a direct empirical observation that can be verified via laboratory testing. The use of 'undetectable' and precise ranges is scientifically precise and appropriate for a descriptive claim based on analytical chemistry data.
More Accurate Statement
“In a sample of 28 red yeast rice supplements sold at mainstream U.S. retailers, monacolin K was undetectable in two products, and concentrations in the remaining 26 ranged from 0.09 to 5.48 mg per 1200 mg of supplement.”
Context Details
Domain
nutrition
Population
human
Subject
Monacolin K in red yeast rice supplements sold at mainstream U.S. retailers
Action
was undetectable in two of 28 and ranged from 0.09 to 5.48 mg per 1200 mg in the remaining 26
Target
Concentration levels of monacolin K in the supplements
Intervention Details
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.
Evidence from Studies
Supporting (1)
Variability in strength of red yeast rice supplements purchased from mainstream retailers
Scientists tested 28 red yeast rice supplements bought in U.S. stores and found that two had no active ingredient at all, while the others had wildly different amounts — just like the claim said. So the study backs up the claim completely.