Glossary

These are general explanations of research terms, not conclusions about any compound. Terms are defined where they appear on research pages; this index collects them in one place.

placebo

An inactive treatment that looks like the real one but contains no active ingredient. Researchers compare a treatment against a placebo to see whether a difference is due to the treatment itself rather than expectation or chance.

randomized controlled trial

A study in which participants are assigned by chance to receive the treatment being tested or a comparison, such as a placebo or standard care. Random assignment helps keep the groups similar, so differences in outcomes are more likely due to the treatment.

cohort study

An observational study that follows a group of people over time to see how exposures relate to outcomes. Because researchers do not assign the treatment, other differences between the groups can influence the results.

confidence interval

A range of values reported around a study result, showing the statistical uncertainty in the estimate. A 95% confidence interval means the method used would capture the true value in about 95 of 100 similar studies.

peer review

Evaluation of a research paper by independent experts before publication. It checks methods and reasoning, but it does not guarantee the findings are correct or will hold up over time.

analytical purity

A laboratory measure of how much of a sample is the intended substance rather than impurities. High analytical purity does not establish sterility, accurate dosing, or safety.

endotoxin

Toxic fragments from bacterial cell walls that can contaminate laboratory preparations. Endotoxin testing checks for this contamination, and it is separate from purity testing.

off-label

Use of an approved medicine in a way not covered by its official authorization, such as a different condition, dose, or population. Authorization applies to a specific product, indication, route, and country.