This story was originally published in The Assembly.
Nabarun Dasgupta spends many afternoons walking through the 200-year-old cemetery across the street from his Raleigh home. Strolling among the gravestones, he thinks about how death is merely part of the process of living, a bookend of a short-term existence.
As an epidemiologist at the University of North Carolina at Chapel Hill who studies street drugs, Dasgupta is used to hearing from colleagues and friends about fatal overdoses. The deaths are not just statistics to Dasgupta. They’re personal. He’s been to a lot of funerals.
“When you’re surrounded by death, it’s easy to get burned out,” he said. “It’s easy to lose sight of what it takes to get up in the morning.”
Dasgupta, 46, has a new reason to be energized by his work. Last month, he was named a 2025 MacArthur Fellow, a prestigious achievement that comes with an $800,000 “genius grant.” The 22 recipients from around the world this year were chosen for their creativity and ability to expand their work.
Dasgupta is widely considered a leading expert in reducing opioid deaths, particularly through harm-reduction efforts like distributing naloxone (a drug that can reverse the effects of an overdose), clean syringes, and fentanyl test strips. Two years ago, he was named to the Time100 Next list of rising leaders.
Dasgupta started Project Lazarus in Wilkes County in 2007, when he was still working toward a doctoral degree in pharmacoepidemiology at UNC-CH. The nonprofit distributed naloxone before such measures gained popularity. Five years later, he cofounded Remedy Alliance, which negotiates with pharmaceutical companies to buy and distribute large supplies of naloxone.
Dasgupta now leads the UNC Street Drug Analysis Lab, which analyzes samples from across the country and publishes the results online. By knowing what’s in the local drug supply—which can include cocaine, fentanyl, methamphetamines, and xylazine—communities and public health officials can better understand how to reduce deaths, Dasgupta explained.
He also partners with health agencies and harm-reduction programs across North Carolina and beyond to better understand what’s happening in communities. The combination of real-time data and real-world relationships gives Dasgupta a unique, often heartbreaking, look at the opioid crisis that has killed more than 1 million people in the United States since 2000.
So, he takes a walk in the cemetery.
But he never stays long. There’s always more work to do, he says, work he hopes can save lives.
Grief and Joy
Dasgupta was wracked with grief after the death of his friend Louise Vincent in late August.
Vincent, who lived in Greensboro and struggled with addiction throughout much of her life, was a fierce advocate of harm-reduction efforts.
Vincent’s work earned her an obituary in The New York Times, which said she overcame “multiple” heroin overdoses over the years. She founded the North Carolina Survivors Union in 2013—which was the same year she had her leg amputated after being struck by a car and graduated with a master’s degree in public health.
“When you’re surrounded by death, it’s easy to get burned out.”
— Nabarun Dasgupta, 2025 MacArthur fellow
A critic of abstinence-based drug treatment programs, Vincent said it was crucial to support people when they have relapses.
“It’s like, ‘Hi, my name is Louise. I can’t stop using drugs, so I need your program,’” she told the News & Record in 2021, according to the Times. “‘Oh, you’re going to kick me out because I can’t stop using drugs? Funny. I just told you that was my problem.’”
Dasgupta and his wife, Roxanne Saucier, who also works in public health, had grown close with Vincent. He said her death at age 49 from a blood disorder and chronic health problems was likely linked to her past use of xylazine, a powerful sedative used in veterinary care.
Vincent was instrumental in the startup of the UNC Street Drug Analysis Lab. The Survivors Union had gotten donated equipment to test drug samples, but she and her staff didn’t know how to use it. So she called Dasgupta, who sent a graduate student to help.
Inspired by the work, Dasgupta’s team at UNC-CH also got a drug-testing machine—and then a bigger, more accurate one.
Dasgupta said it was an emotional day when he told his staff about Vincent’s death. “We were all pretty upset. I walked back into my office on campus and turned off the lights and was just going to sit with the pain for a bit.”
Then Dasgupta’s phone lit up with a call from a Chicago area code. He figured the city’s health department was calling about a contract for drug testing. But it was someone from the John D. and Catherine T. MacArthur Foundation telling him he had been selected. The process is highly secretive; Dasgupta didn’t even know he was in the running.
“Clearly the expectation was unrestrained joy, and all I could do was think of Louise,” he said. “It was so super intense, and it felt like Louise’s parting gift and her encouragement to keep going.”
‘I Found My Calling’
After growing up in Maine, Dasgupta studied molecular biology at Princeton University. He found chronic viral infections like HIV and hepatitis, which are linked to intravenous drug use, fascinating.
Dasgupta then headed to Yale for a master’s degree in epidemiology and considered going to Thailand and Cambodia to study dengue, a viral infection spread by mosquitoes. Then, after the September 11, 2001 terrorist attacks and the anthrax incidents that killed five people in subsequent weeks, he instead planned to take an internship focused on bioterrorism preparedness.
He didn’t take that job either, opting to return to Maine to study the powerful painkiller OxyContin, which was later blamed for fueling the opioid epidemic. “I ended up doing the field work and doing a lot of interviews that summer in Portland, really learning about what drug use was actually like,” Dasgupta said. “I guess that was it—I found my calling.”
In Chapel Hill, Dasgupta is an Innovation Fellow at the UNC Gillings School of Global Public Health and a Senior Scientist at the UNC Injury Prevention Research Center.
“He specializes in turning research into practice, and through his work, he amplifies community and patient voices in public health and provides innovative health-tech and community-based solutions,” Dr. Nancy Messonnier, dean of the Gillings School, said in an announcement of the MacArthur.
Over the last few years, his drug lab has analyzed about 16,000 samples from 40 states. Dasgupta said his team has detected more than 450 unique substances—everything from caffeine to synthetic opioids like fentanyl and nitazines.
Dasgupta’s crew packages collection kits that include a small vial, a pencil, and a card to fill out information about where the drugs came from, which are then shipped to health departments, harm-reduction programs, and other partners. After UNC-CH tests the samples, anonymized results are immediately posted online, providing a real-time glimpse of what is in the drug supply.
“He amplifies community and patient voices in public health and provides innovative health-tech and community-based solutions.”
— Dr. Nancy Messonnier, dean of the Gillings School of Global Public Health
Most street drugs in the United States contain a mixture of substances, Dasgupta said, which can lead to deadly consequences. UNC-CH freshman Elizabeth Grace Burton died on the Duke University campus in 2023 after using cocaine that was later determined to contain fentanyl.
Sampling can also help explain sudden changes in drug users’ experiences. When a Pittsburgh group reported that fentanyl users were having certain types of hallucinations not typically associated with opioids, Dasgupta said, his lab identified medetomidine in a sample—a powerful veterinary tranquilizer.
In Western North Carolina’s Madison County, health advocates suspected the local supply of methamphetamines had become more potent after police arrested some suppliers. So they sent older and newer samples to the lab to compare. They were right.
“Then they were able to do some on-the-ground sleuthing and realized that there was an influx of a new supply from the shitty tail end of the distribution chain from Atlanta,” Dasgupta said.
Erin Tracy, a research chemist and North Carolina State University graduate, conducts much of the drug testing in the UNC-CH lab.
She met Dasgupta during the pandemic, when she was considering her next career move after a decade as a drug analyst at government crime labs in Georgia and Wake County. Now she appreciates the positive impact of her work.
“The science is the same that I was doing in the crime lab,” Tracy said, “but it was used to penalize people within the criminal justice system, rather than within the sphere of public health to help empower people.”
Drop in Overdoses
Dasgupta knew something had changed in the drug market when he began to receive fewer late-night phone calls about fatal overdoses.
The number of people who died of drug overdoses in North Carolina had climbed in the early 2010s to a peak of 4,422 people in 2023, according to the state Department of Health and Human Services
But the state saw a staggering 32 percent drop in 2024. The trend matched what other states were also starting to see.
Dasgupta cautions against the assumption that opioid drug use has become less common; he believes many opioid users have simply gotten better at avoiding an overdose.
Like other health experts, Dasgupta says naloxone and increased treatment options are keeping more people alive. And there are signs that less fentanyl is making its way into the United States, making opioids less potent.
Generational shifts are also at play, he said. Generation Z—those born between the late ’90s and early 2010s—aren’t as interested in opioids, likely because they saw the devastation in their parents’ and grandparents’ generations.
“They have their lived experience,” Dasgupta said, “and what they’ve learned is so much more powerful than any educational message is ever going to be.”
But testing is still crucial, he says, especially as the drug supply remains unpredictable. Machines that quickly analyze street drugs have become more common at places like music festivals.
Dasgupta wants more harm-reduction programs and public health agencies to have access to drug-testing equipment. He hopes to receive a grant from the Foundation for Opioid Response Efforts (FORE) early next year that will allow his lab to train others throughout the country.
He is considering using the money from the MacArthur grant to study the drug supply “from a hemispheric perspective,” while advocating for harm reduction in Latin America. He also wants to write a book about the 300-year history of drug use in the United States.
His “genius” status comes with some perks. When UNC-CH Chancellor Lee Roberts called Dasgupta to congratulate him, he asked if there was anything he could do to support him. At the urging of Dasgupta’s 12-year-old son, he asked for coveted tickets to the UNC basketball game against Duke.
“So he said he’d invite us,” Dasgupta said. “It was a fun, jokey conversation, like all it takes to get Duke-Carolina tickets is to win a MacArthur. So now we know.”
