Again, that doesn’t mean senolytic drugs that target “zombie cells” won’t work. But it feels as if many in the field have moved on. These days, the buzz is all about ✨reprogramming✨.

The idea here is to essentially return cells to a young state. It’s based on the Nobel Prize–winning discovery that four genetic factors can turn an adult cell into a stem cell, which can be encouraged to develop into pretty much any other cell type.

Some promising studies in mice suggest that this approach might help wind back the clock. It seems to improve tissue healing, restore vision, and even improve learning and memory.

Running parallel to all this research are repeated injections of hundreds of millions of dollars in funding. In 2021, my colleague Antonio Regalado reported on the founding of the biotech company Altos Labs to pursue reprogramming for rejuvenation.

Altos was funded by the billionaire Yuri Milner—reportedly along with Jeff Bezos, among others—to the tune of $3 billion, a previously unheard-of figure for a biotech startup. Other well-funded companies have since sprung up in this space.

There’s Retro Biosciences, for instance, which is pursuing reprogramming (among other approaches) in an effort to add 10 years of healthy life to human lifespans. Retro’s launch was supported by $180 million from OpenAI’s Sam Altman. Last month, the company announced a valuation of $1.8 billion.

NewLimit, another billionaire-backed biotech exploring reprogramming, says it has promising results from research in mice. It plans to trial a drug designed to rejuvenate the liver in people next year. Last week, the company announced it had raised $435 million toward reaching that goal, among others.

Life Biosciences, which was founded by the Harvard biologist David Sinclair, most recently secured $80 million to support its research. The eye trial is now officially underway, but Sinclair also has plans for whole-body rejuvenation. Earlier this week, he told my colleague Antonio that he plans to test a “highly, highly confidential” oral reprogramming drug as part of a $101 million competition organized by the XPrize Foundation.