Peptides are suddenly everywhere — touted by influencers, biohackers and longevity enthusiasts as the next breakthrough in wellness. But what exactly are they, and how much do we actually know about the risks?

Host Megan McArdle talks with physician and Washington Post columnist Dr. Leana Wen about the booming peptide economy, the rise of gray-market injections and why so many people are turning to online health communities instead of doctors. As wellness culture pushes further into self-experimentation, how much risk are people willing to take in the pursuit of optimization?