Dietary supplement sales have surpassed $30 billion per year with their use becoming and remaining extremely popular amongst the general public. There are numerous bioactive components, both nutritive and non-nutritive, in dietary supplements with considerable efficacy in promoting health. However, there are many ways disallowed ingredients may enter the supplement pipeline with potentially toxic effects. Dietary supplements can be regulated (either pre-or post-market) as a drug, dietary supplement, a nutraceutical, new dietary ingredient (NDI), generally recognized as safe (GRAS) food ingredient, a food additive, or a food. A pharmaceutical drug (medication) is used to treat, cure, prevent, or diagnose a disease and is regulated by the FDA pre-market only and allowed by medical prescription, whereas the other labeling designations are largely regulated post-market. One such molecule with a labeling problem is tianeptine, which has global use as an efficacious, prescribed drug, while at the same time being considered a non-drug and potentially dangerous adulterant often referred to as gas station heroin. In this paper, we critically evaluate the use and labeling of this compound and attempt to clarify the conundrum surrounding its legal or illegal use. Tianeptine is effective and efficacious as an antidepressant in those responding poorly to selective serotonin reuptake inhibitors (SSRIs) and exhibits many medicinal characteristics of tricyclic antidepressants with fewer opioid-like side effects. As a result, sixty-six countries permit use of tianeptine as a prescription drug. At higher doses, tianeptine has recently been shown to exhibit significant potential for abuse and dependency along with toxicity. As such, the US does not recognize tianeptine as an FDA-approved drug or as a dietary supple-How to cite this paper: Martin, K.R.