Stem Cells, Cryonics, and the Drugs That Might Slow Aging: What People Are Actually Trying

Set aside the philosophy for a second. Strip away the interviews and the manifestos, and the medical side of this movement comes down to three separate bets, aimed at three different points in time: preserve the body now in case the future can fix it, repurpose today's drugs to slow damage before it accumulates, or replace damaged tissue directly. Cryonics, longevity drugs, and stem cells. None of them are the same bet, and they're not equally far along.

Cryonics is the oldest and the strangest-sounding, which is partly why it gets treated as a punchline. It isn't new: the modern practice traces to Robert Ettinger's 1962 book "The Prospect of Immortality," which argued that freezing the body at death, however imperfectly, was strictly better than the alternative — you lose nothing by trying that you weren't going to lose anyway. Alcor Life Extension Foundation, the largest cryonics organization, vitrifies bodies or just brains in liquid nitrogen on the bet that a future technology, not yet invented, will be able to repair the damage and revive the patient. Cryonics advocates often describe it less as a guarantee and more as a hedge — a chance you wouldn't otherwise have. Alcor has never publicly confirmed its membership list, but Peter Thiel's Alcor membership has been reported in multiple profiles over the years. Nobody has ever been revived. Nobody claims otherwise. The entire premise rests on technology that doesn't exist yet.

Drugs are the closest thing to near-term. Rapamycin, originally an organ-transplant anti-rejection drug, reliably extends lifespan in mice across many independent labs — one of the most replicated findings in the whole field — and is now taken off-label by a growing number of longevity-focused physicians and their patients, years ahead of any aging-specific approval. Metformin, a decades-old diabetes drug with an unusually clean safety record, is the subject of the TAME trial (Targeting Aging with Metformin), led by Dr. Nir Barzilai at Albert Einstein College of Medicine — a study designed explicitly to convince the FDA to recognize aging itself as a treatable target, not just the diseases downstream of it. That regulatory question — whether "aging" can even be an approved indication — is arguably a bigger bottleneck right now than the biology. Then there's David Sinclair, the Harvard geneticist and bestselling author of "Lifespan," who has said flatly that aging is a disease and that disease is treatable. It's a good line. It's also one a number of his scientific peers have publicly pushed back on, arguing his public claims outrun what his own published data supports — worth knowing before you take any single scientist's confidence as consensus.

Stem cells are the murkiest of the three, because "stem cell treatment" covers both real, narrow, FDA-approved medicine (certain blood cancers, some corneal and orthopedic repair) and a much larger, largely unregulated industry selling unproven injections marketed as anti-aging or regenerative, often at clinics outside the US specifically to dodge oversight. The FDA has issued repeated public warnings about unapproved stem cell products; the gap between what's rigorously proven and what's being sold under the same name is enormous, and it's the buyer, not the clinic, who absorbs that risk.

None of this adds up to a cure for aging. It adds up to three genuinely different, genuinely funded bets, running at three different speeds, with three different risk profiles — which is a more useful way to track this space than treating "anti-aging medicine" as one thing.