Preliminary Characterization of Commercial Kratom Extract Products

Inclusion Criteria:

* 1\) \>21 years old;
* 2\) Experienced kratom extract product consumer of one of the leading US brands listed in the study protocol;
* 3\) Reports a specific kratom extract product brand and specific dose amount (or range of typical dose amount) on the online screener;
* 4\) English language proficient;
* 5\) Willingness to provide requested samples of the kratom extract product currently being taken.

Exclusion Criteria:

* 1\) Reports any acute adverse or unexpected or otherwise sudden health event related to their typical kratom product dose that occurred within 30 days of screening;
* 2\) Having ever sought medical attention for an acute adverse health event as a result of taking any kratom product;
* 3\) Cannot or will not provide their kratom extract product samples in the form of an unopened package that is clearly labeled with at least the product and vendor name;
* 4)The kratom extract product used by the participant has any semi-synthetic or fully synthetic ingredient listed or is known by the study team to have such an ingredient;
* 5\) Currently breastfeeding or pregnant;
* 6\) history or current diagnosis of psychotic disorder;
* 7\) current untreated bipolar disorder; 8) current untreated major depressive disorder;
* 8\) Current physical dependence on alcohol, benzodiazepines, or opioids (self-reported or otherwise evidenced) requiring medical intervention;
* 9\) Reports use of fentanyl within the past month and/or has a fentanyl positive drug screen;
* 10\) Discordance between self-reported substance use and drug screen results obtained during screening;
* 11)Any physical, psychiatric, environmental, situational, or kratom product-related condition considered by the study team to increase risk or undue burden.