I was pleased to contribute to a new @NatGeo article from Hannah Singleton out today exploring one of the more interesting questions in longevity science: Could GLP-1 drugs actually slow aging? It’s a thoughtful look at both the excitement around GLP-1s and the important uncertainties that remain. My view is that there is compelling evidence that GLP-1s can improve multiple aspects of health in humans. Beyond weight loss and glucose control, there are signals for cardiovascular, kidney, inflammatory, and perhaps neurological benefits. That makes me optimistic about the use of GLP-1 agonists in proactive healthspan medicine, potentially at doses and quite different from those currently used to treat obesity. But, do they slow aging? And if so, are they anything more than a pharmaceutical way to induce caloric restriction? The recent @Nature paper showing that semaglutide extends lifespan and improves multiple age-related phenotypes in mice is interesting. As I’ve commented publicly, however, the lifespan experiment did not include a calorie-restricted control matched for the reduced food intake caused by semaglutide. Weindruch and Walford showed in 1982 (DOI: 10.1126/science.7063854) that mid-life initiation of moderate caloric restriction increases lifespan in mice by almost exactly the same amount, in the same mouse strain background, as semaglutide in the current study. So, we still don’t know whether semaglutide is doing something fundamentally different from, or additive to, eating fewer calories. Regardless of the answer, I think these are extremely promising drugs when used carefully, in the context of high-quality nutrition and regular exercise, expecially resistance training to maintain muscle. In fact, GLP-1s could ultimately prove extremely valuable for extending healthspan, even if they don’t slow biological aging at all. Preventing or delaying several major causes of morbidity could have enormous value independent of whether we ultimately classify these drugs as true gerotherapeutics. For me, the most interesting next step is figuring out whether there are doses and protocols where the healthspan benefits substantially outweigh the risks, particularly in otherwise healthy middle-aged and older adults. That’s a question we can answer, and I'm optimistic the answer will be "yes". nationalgeographic.com/healt…