In the late 1950s, a tuberculosis drug was repurposed as the world’s first antidepressant. Then the selective serotonin reuptake inhibitor (SSRI) Prozac ushered in a new era of antidepressants. Today SSRIs are some of the most widely prescribed drugs in the country, but gaps still exist in our biological understanding of mental health, the overall efficacy of antidepressants, and predicting serious side effects. In response, some scientists and physicians are turning to different classes of drugs altogether to treat depression.

Transcripts and episode sources at acs.org/chainreaction

The discovery of sex hormones in the 1930s led to the development of female birth control, a widely used class of drugs that reshaped cultural norms surrounding fertility and bodily autonomy. But contraception remains largely the responsibility of women. On today’s episode: the evolution of birth control and the future of male contraception.

Transcripts and episode sources at acs.org/chainreaction

Through a few serendipitous discoveries, antibiotics changed the course of history by turning deadly infections into manageable sicknesses. But it didn’t take long for bacteria to begin outsmarting these wonder drugs. On today’s episode: The fascinating world of antibiotics and the efforts to tackle antibiotic resistance, including using AI to come up with new drugs that will only become more essential.

Transcripts and episode sources at acs.org/chainreaction

You’ve likely relied on a drug at one point or another, whether it be a prescribed medication or something over the counter. The upcoming miniseries of Chain Reaction explores the history, impact, and future of major drug classes, including antibiotics, birth control, antidepressants, and GLP-1s. Margot and Sam will chat with experts about the history and scientific breakthroughs behind these medicines and the ongoing research that could shape the next generation of drugs.

Transcripts and episode sources at acs.org/chainreaction

This bonus episode continues the celebration of the American Chemical Society’s 150th anniversary by spotlighting two remarkable ACS presidents whose work helped shape public health in very different ways. Hosts Margot and Shane trade stories about these pioneering chemists.

Harvey Wiley, ACS president in the 1890s, investigated dangerous food additives like formaldehyde and borax and presided over the infamous “Poison Squad” experiments. He was part of the impetus behind the “Wiley Act,” also known as the Pure Food and Drug Act of 1906.

Helen M. Free, ACS president in the 1990s, transformed urinalysis diagnostics, co-inventing the first glucose test and countless other tests. Free’s innovations made health monitoring more accessible for millions of people and her legacy continues through the ACS award that bears her name. Learn more and send in your nominations here.

Transcripts and episode sources at acs.org/chainreaction

To cap off this special #ACS150 miniseries, we chat with chemistry educator, science communicator, and social media creator Kim Hilton — better known as Chemical Kim (follow @chemicalkim).

Kim reflects on her unexpected path into teaching, from struggling to understand chemistry as a college student to becoming a professor who has spent three decades helping others discover their place in STEM. The conversation explores Kim’s passion for outreach, from creating hands-on science experiences for children in hospitals and community programs to building an online audience that spans generations. Along the way, Kim explains why making chemistry accessible is not the same as making it easier, and why educators must meet learners where they are to help them succeed.

Transcripts and episode sources at acs.org/chainreaction

Space is the place . . . for chemistry! ACS president-elect Chris Bodurow and three colleagues chat about the role of chemistry in space exploration and how they ended up working in such an exciting field. Luke Roberson, Ken Savin, and George Rodriguez highlight the expanding space industry, the technologies that chemistry has enabled in space, and how chemistry might change the industry in the future by, for instance, enabling long-term life-support systems. Across all conversations, one thing becomes clear: Chemistry is enabling humanity to explore, live, and innovate in space.

Transcripts and episode sources at acs.org/chainreaction

ACS president Rigoberto Hernandez invites colleagues to speak about mentorship, communication, and the human side of science. One of Rigoberto’s former students, Ashley Ringer McDonald, talks about the power of multi-directional mentorship and the importance of nurturing growth and confidence in students. Michelle Francl and Rigoberto discuss the evolving role of theoretical chemistry, the need to balance basic and applied research, and the importance of communicating science in accessible, engaging ways. The episode closes with Angel Martí, who reflects on inclusive mentoring, community-building, and creating a sense of belonging to retain diverse talent in STEM. Across these conversations, a central theme emerges: science is fundamentally a human endeavor shaped by relationships, communication, and shared curiosity.

Transcripts and episode sources at acs.org/chainreaction