Connecticut officials this week classified tianeptine as a Schedule I controlled substance, making the sale and possession of the drug illegal in the state as of Wednesday. The move places Connecticut among a growing number of states taking action against the substance over safety concerns.

Tianeptine, a tricyclic antidepressant, can produce euphoria in high doses and is more potent than morphine and addictive opioids, according to the U.S. Food and Drug Administration. Misuse can cause severe health effects, including respiratory depression, sedation, and death.

The drug is often sold at convenience stores, gas stations, vape shops, and online, marketed under names like Tianaa, ZaZa, Neptune’s Fix, Pegasus, and TD Red. Some products are promoted for pain, anxiety, depression, or mental alertness, and may be flavored to appeal to younger consumers.

Connecticut Lt. Gov. Susan Bysiewicz said the Schedule I classification is necessary to protect residents from addiction. “With false marketing that led consumers to believe these are safe products, and with candy-like flavor options, these substances posed a clear threat to those battling substance-use disorder and our youngest residents,” she said. The state also added kratom, nitazenes, phenibut, and other substances to its controlled list.

FDA Commissioner Martin Makary has raised alarm over tianeptine, calling it a “dangerous and growing health trend” that poses serious risks to youth. Medical experts, including Dr. Robert Schwaner of Stony Brook Emergency Medicine, note that while low doses affect serotonin, higher doses act on mu-opioid receptors, potentially leading to fatal respiratory failure similar to heroin.

Experts warn that tianeptine’s addictive qualities, including tolerance, dependence, and withdrawal, make it a candidate for national regulation. The Connecticut ban reflects growing state-level efforts to limit access to the substance.