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Common Exclusion Criteria That Surprise Participants

A practical overview of why seemingly minor details can affect eligibility.

Last updated: February 27, 2026

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Frequent surprises

  • Medications or supplements that conflict with the protocol
  • Recent participation in another study
  • Abnormal lab values discovered at screening
  • Shift-work schedules or inconsistent sleep patterns
  • Travel or scheduling limitations that make protocol timing unrealistic

Practical takeaway

Eligibility is not a judgment about health or reliability. It is a protocol requirement. The most productive approach is to ask which categories tend to be disqualifying before investing more time in the process.