Adverse event

The wording comes from US rules for safety reporting in investigational drug trials, which define an adverse event as "any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related" [3]. The same rules call an event serious when, in the view of the investigator or sponsor, it results in death, a life-threatening adverse event, inpatient hospitalization or a persistent or significant incapacity, among other outcomes [3].

Because the definition ignores cause, a headache in the placebo group of a trial counts as an adverse event just as one in the supplement group does. The main CONSORT guideline for reporting randomized trials asks authors to report all important harms or unintended effects in each group [1]. CONSORT Harms 2022 replaced a 2004 harms checklist that had not been consistently applied, modifying 13 items of the main CONSORT checklist to improve harms reporting and adding 3 new ones [1].

Outside trials, regulators collect reports in databases such as the US Food and Drug Administration's CAERS, which researchers have searched for adverse events linked to supplements [2]. NootropicsWork reads these reports as signals, not as proof that a product caused an event.

Read the comparison, not the count. A statement that adverse events were similar to placebo means the rates did not differ between groups; it does not mean nothing happened. "Side effect" is not one of the terms these rules define; the formal terms separate what happened, an adverse event, from what the product is reasonably thought to have caused, a suspected adverse reaction [3].

Monographs on this site report adverse events as each trial or review records them, with the comparison group named, and keep serious events apart from mild ones.

• Hepatotoxicity
• Contraindication
• Interaction
• Tolerable upper intake level